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Field Journal

When Philip Johansson joined an Earthwatch-supported dinosaur dig led by Dr. Marilyn Wegweiser (Georgia College and State University), he expected to be astounded. He would be one of the first living beings to lay eyes on a creature since it was buried 67 million years ago. What he didn't expect was a journey into his own personal reality of time.

Elk Basin, Wyoming — It was a champagne moment at This Side of Hell, as the quarry had become known. There was no champagne available in this quiet stretch of Wyoming high desert, but the effect was just as giddying. Two team members had just helped “Doc” Wegweiser remove a chunk of rock to reveal the full length of a perfectly preserved scapula as long as my arm, and discovered yet another brick-red bone lying beneath it. The elegantly curved scapula was one of the most beautiful things I had ever seen, dead or alive, and we all gathered around to ogle and coo.

The quarry was on a ridge-top within Elk Basin, a craggy depression on the Montana border inhabited by piñon jays, rock wrens, golden eagles, feral cows, coyotes, and the restless ghosts of dinosaurs. Doc calls Elk Basin a “doubly plunging anticline,” which is a fancy way of saying a giant, rising wrinkle in the Earth's crust. The crest of the wrinkle has eroded away, revealing layer after layer of sedimentary rocks that “plunge” at a steep angle toward the edge of the basin, five kilometers wide and twelve kilometers long. The ridges and valleys within Elk Basin represent the whole of the Mesozoic Era, the age of dinosaurs, with the deepest, oldest layers toward the basin's middle.

It occurred to me, standing over that scapula on a windswept ridge, that the basin was like a human soul laid bare. Each layer of rock was like a life-altering event, with the oldest, most fundamental experiences at the center encrusted with layer upon layer of newer refinements. Each flake of sandstone was like a moment, embedded in the past and embracing the future.

Humans are unique in being the only creatures in nature who spend a significant amount of time ignoring the present. While rock wrens and coyotes live each moment as if their lives depend on it, which their lives so often do, we preoccupy ourselves with past regrets and future stratagems. Humans compartmentalize time, prioritize their days, denying themselves the depth of each moment. It takes unwavering attention to experience every moment as unique, yet inseparably nested in the past and in the future like the tilting layers of Elk Basin.

Each layer in the basin held a story, a memory. The dinosaur we were excavating was a large hadrosaur, or duck-billed dinosaur, that apparently was over-whelmed in a flood of sediment near the edge of a Cretaceous sea. The shifting sands in the flood came from the erosion of newly formed mountains that were pushing above the horizon to the west, to become the present Beartooth Range. Two of the hadrosaur's ribs showed evidence of a violent attack, perhaps from a giant therapod like Tyrannosaurus. Footprints near the fossil bones suggest that a two-footed scavenger, on the scale of a Deinonychus, was perhaps the last being to set eyes on the carcass before we did, 67 million years later.

Other layers held different memories, but each was an integral part of the basin, of the whole story. In an earlier layer known as the Meteetse Formation, crumbling bone fossils and charred petrified wood evoked spewing volcanoes and forest fires that raged for centuries. In this formation, Doc had found charred bones that suggest that dinosaurs died in such fires. Near the top of the Meteetse, we observed hundreds of footprints from a large hadrosaur, perhaps like the owner of that exquisite scapula on the next ridge. The track ways told many stories and revealed behavioral traits: One ancient reptile put down a forepaw for balance much as a kangaroo would today.

At another site, Doc showed us fossil ammonites, cone-shelled mollusks related to the present-day chambered nautilus, which represented a period when the land here was under the ocean. And near the edge of Elk Basin, we observed the border between the Cretaceous and the Tertiary, known as the KT boundary, indicating the end of the dinosaurs' reign and the ascendancy of mammals on the Earth. That story, its drastic environmental changes and fatal implications for dinosaurs, is one that is still waiting to be told. The missing clue could be right here, in the pages of Elk Basin.

That evening at the quarry, storm clouds rolled in from the Beartooths, and a rainbow arched over the limber pines dotting the ridge top. A flock of nighthawks fluttered above us, their white-blazed wings flickering in the fading sunlight. From the next ridge a coyote called, breaking the desert silence, and then another from even closer. It was a moment that I cherished, as precious as a rare find, embedded in the past and embracing the future. I plan to have many more.

PHOTOS (COLOR): The unearthed rib bone of a hadrosaur (bottom left) shows evidence of an injury incurred 67 million years ago, one of the many stories told in the layers of Elk Basin. Team member Deborah Gentry (center) whisks away layers of sandstone to reveal more ribs for preservation.

5.Creationist Geologic Time Scale: an attack strategy for the sciences.

Should the scientific community continue to fight rear-guard skirmishes with creationists, or insist that "young-earthers" defend their model in toto?

Donald U. Wise, Professor Emeritus, University of Massachusetts at Amherst, and Research Associate at Franklin and Marshall College, Lancaster, PA. email: [email protected]

This article is an expanded version of an original manuscript that was published in American Scientist, March/April, 1998, vol. 86, n. 2, p. 160-173.

Introduction

This manuscript proposes a new approach for science's battle against the rising influence in America of pseudo-science and the Creationist movement. The framework of Creationist Bible-based earth history, focusing on Genesis and the Noachian flood, can be assembled into a single geologic time scale (Figure 1, enlarged by addition of many geologic facts, difficult for Creationists to explain. (Figure 1 is an abbreviated version of the time scale outlined in the following paragraph which was redrawn and published by the American Scientist.) Some of the items are so absurd that all but the most dedicated fundamentalists will see the overall picture as scientific nonsense, even bordering on humor, a most rare commodity in Creationist literature. Science, rather than using its traditional defensive approach of item-by-item rebuttal of Creationist attacks, needs to take the offensive by challenging Creationists to defend their "scientific" view of earth history as represented by this time scale. (Note that the numbered items in this Time Scale are further expanded in subsequent numbered sections which are keyed to these same numbers.)

A Creation "Science" Geologic Time Scale

(1) 4000 B.C. Creation Week: (laws of science suspended)

Day 1 - Space, light & dark, earth materials.

Day 2 - Waters above and waters below.

Day 3 - Earth's crust and plants.

Day 4 - Sun, moon, and stars in place.

Day 5 - Atmosphere + animals of the waters.

Day 6 - Land animals + Adam & Eve.

Day 7 - Day of rest.

1,500 years. Pre-Flood "Geology." Laws of science invalid.

(2) Adam and Eve, talking snakes, etc.

(3) World's waters are in great Venus-like atmosphere or in ground

water. No rain, no ocean basins.

(4) Radiometric dating invalid; speed of light changed.

(5) Humans, dinosaurs, mammals, the "works," all live together in

peace. Both lions and Tyranosaurus Rex are vegetarians in Eden before

the "fall."

(6) Human life spans up to 900 years.

(7) Battle of Satan and angels produces craters on moon.

Flood Year: Flood "Geology" - ONE (?) year of normal (?) "science"

Rain - 40 days

(8) Big animals run to mountain tops. Not a single dumb human caught

in all the early flood sediments. All dinosaurs washed off only in

middle flood-time.

(9) Coral reefs (Guadalupe Mountains of Texas) grow to thicknesses of

half a mile during single year.

(10) Vast coal beds accumulate one on top of another, each as original

swamp deposits on order of 100 feet thick, all in one year.

(11) Mile-thick salt formations in Utah form by evaporation (!) of

seawater during (!) the flood.

Flood - about 250 days.

(12) Most of the world's sedimentary rocks dumped on continents to

average thickness of one mile, almost entirely during the flood year.

(13) Most continental drift occurs. Flood waters drain into the newly

formed ocean basins. Atlantic opens at average rate of 1/2 mile per

hour.

(14) Most deep sea sediments (average about 1,500 feet thick) collect

on the newly opened ocean floors.

(15) Hawaiian volcano built 30,000 feet high on new sea floor. (Cools

enough for birds and plants from Ark to colonize soon after end of

flood year.

Final Retreat - ? 100 days ?

(16)Volcano of Mount Ararat built 7,000 feet high underwater and cools

in time for grounding of the Ark.

(17) Successive Yellowstone ash beds bury 10 to 27 forests one on top

of another, all grown during single year.

(18) Grand Canyon cut by receding flood waters. Flood sediments

de-water and harden in one year to rock strong enough to stand as

steep, mile-high cliffs.

Post-Flood Geology - 4,500 years of normal (?) science to

Present

(19)From Ark, Noah (?) directs streams of distinctive animal and plant

communities to migrate to Africa, Australia, South America, etc.

(Ferry service ?) (Some creationists use post-flood continental

drift at rates up to one mile per hour !)

(20)Sun stands still for Israelite battle. Earth stops rotating and

then starts again due to near-miss by Venus out of its orbit ?

(Velikovsky)

(21)Only one ice age as post-flood atmosphere cools.

Geologists' abundant evidence of many great ice advances

separated by sub-tropical vegetation and development of thick soil zones

between some advances are wrong.

(22)Late-flood granite masses, formed at 1,000 degrees (F.), cool to

present low temperatures at rates in violation of all laws of thermal

physics. Fit to radiometric dates is mere coincidence.

(23)Extreme rates of continental drift typical of flood (1/2 mile per

hour) suddenly slow to present-day laser-measured rates of inches per

year. Accord of present rates with radiometric dates is mere chance.

(24)Coral reefs (Bikini, Eniwetok) grow 1/2 to 1 mile thick in first

1,000 years (rate of one foot per month) then slow to present measured

rates of inches per century.

Figure 1. (GIF, 168K)

Figure 1. Unlike the 4.5-billion-year-old geologic time scale that has been developed through a century and a half of scientific research, creationism's geologic time scale compresses the history of the universe into about 6,000 years, requiring that radiometric dating be discredited and that many of the steps in the formation of the earth were so accelerated that millions of years of geologic change were accomplished in a few days or weeks. The entire fossil record of the earth is explained as having been deposited during the year of the Noachian flood 4,500 years ago.

Creationism has its philosophical roots in the Darwinian debates of the last century, but its welding into a potent political movement has been largely a phenomenon of the last half of the 20th century (Numbers, 1993). In recent years Creationism has grown into a force capable of challenging orthodox science in the arena of public opinion (Schmidt, 1996). After federal courts struck down attempts to force teaching of creation "science" in the public schools, Creationists have taken a new approach. They have begun pushing laws requiring that any teaching of evolution in the public schools be balanced against or accompanied by teaching of the "evidence against evolution." In effect, this "evidence" consists mostly of Creationism's religion-based pseudo-science. Such laws, if enacted, would have chilling effects on science teaching and textbook content and would lend governmental support to one particular religious interpretation.

The real battles (Schmidt 1996) between traditional science and Creationism are likely to be fought on a state by state, school board by school board basis in a form that will require active, grass-roots participation by large numbers of American scientists. Unfortunately, most of us are essentially unarmed for such battles. While Creationists regard this as a holy war worthy of their almost undivided attention, most scientists have given it short shrift, either by ignoring it or by laughing at such pretensions of "science." As a result, most scientists remain so unfamiliar with the claims, methods, and arguments of Creationists that they are unprepared for participation in any public confrontation. A notable exception was the late Robert Dietz of Arizona State University who used both science and humor of the cartoons of John Holden (Dietz and Holden, 1987) to actively debate the local Creationists. Excellent descriptions of methods used by Creationists to win such debates, at least in the public mind, are given by Thwattes and Awbrey (1993), Fezer (1993), and Arthur (1996). To develop any level of preparation for such arguments and methods, one requires copious time as well as access to the diffuse mass of "gray" publications, religious tracts, and other in-house Creationist publications. For those without the time or access to such resources, this article is intended as a "crash-course" introduction to Creationist history, ideas, and methods as well as some factual tools to oppose Creationist claims and a few of the best cartoons to inject a bit of humor into any discussion (Figure 2).

Figure 2 (GIF, 72K)

Figure 2. Creationists offer a cartooned view of science that is often hard to address in public debate. Creationism, itself, meanwhile, has tempted a few cartoonists to take up their pens. John Holden, a paleontologist by training (and co-author with R. S. Dietz of a cartoon commentary, Creation/Evolution Satiricon), has pondered the implications of Henry Morris' explanation of lunar craters as the result of cosmic battles between Satan's angels and those of the Archangel Michael.

Some Creationist History

Numbers (1993) gives a massively documented history of the Creationist movement from which much of the following is excerpted. In the 1930s a group of mostly Seventh Day Adventists founded the Deluge Geological Society (DGS) while in the 1940s a second group, mostly Baptists associated with Wheaton College, founded the American Scientific Affiliation (ASA). The ASA focused on the interplay of Christianity and science whereas the DGS sought to bring interpretations of the geological record into accord with a strict Biblical interpretation.

The ASA and DGS merged briefly in the 1940s but ultimately split largely after a talk given by a young ASA member, J. Lawrence Kulp. Kulp studied C14 dating methods with Urey at Chicago and then set up the second C14 lab in the country at Columbia University. On the basis of emerging C14 results, Kulp told the combined group in 1949 that there was no escaping an interpretation of great antiquity for the human race. The result was a permanent rift. In the 1950s Ph.D. hydrologist and fundamentalist, Henry M. Morris, and broadly educated seminarian and Bible teacher, John C. Whitcomb, Jr., joined forces. They updated many of the ideas of George McCready Price's New Geology (1923) to produce The Genesis Flood (Whitcomb and Morris, 1961). Morris believed the ASA "was too permeated with evolution ever to be reclaimed." He and eight like-minded individuals, including Ph.D. biologist Duane Gish, met in 1961 with the purpose of founding a new group based on the philosophy and ideas of the book. Out of this nucleus came the Creation Research Society (CRS) in 1963 and the scientific creationist movement.

Largely under the influence of Morris and Gish, the CRS has grown into a national and international network of organizations with links to the parent Institute for Creation Research (ICR). The ICR in the San Diego area now operates as a degree granting organization, accredited by California's State Department of Education, offering M.S. degrees in biology, geology, astro/geophysics, and science education. California removed its accreditation in 1990 but had to restore it two years later under orders of a federal judge (Numbers, 1993). The Institute publishes many books and articles and sponsors its own Bible oriented "research" studies and symposia. Currently it is reputed to operate on an annual budget of 3 million dollars (Scott, 1996).

The New Crop of Creationist Geologists

One of the greatest anomalies in the history of scientific creationism and flood geology has been the near non-presence of well educated geologists (Numbers, 1993). Even most of the promising young evangelicals who undertook advanced work in geology emerged with badly shaken faith in strict Creationism. J. Lawrence Kulp was mentioned above. F. Donald Eckelmann, a Wheaton alumnus, ultimately became chair of Brown University's geology department and Christian evolutionist. Davis Young, the son of an eminent Old Testament scholar, studied geology at Princeton and moved on to M.S. work at Penn State, still a believer in the Morris version of the Genesis flood. During his Ph.D. work with Eckelmann at Brown, Young became more and more disenchanted with Creationist ideas, subsequently writing a book (1977) charging flood geologists with teaching "bad geological science." The same scenario ensued for Nicholas Rupke, a Dutch student of P. H. Kunen, who submitted a manuscript on cataclysmal sedimentation for publication by the CRS. At CRS urging Rupke came to Princeton in 1968 and completed a Ph.D. in 1972 under F. B. Van Houten and A. G. Fisher. He finished by accepting organic evolution and forsaking the faith of his family, going on to Oxford and a career in the history of science. Harold James, Jr., and Edward Lugenbeal attended the Seventh Day Adventist Theological Seminary before being recruited to do graduate work at major institutions at the expense of the Adventist Geological Research Institute. James, after earning his doctorate in geology at Princeton, was found to have been "so indoctrinated" as to require dismissal by the GRI. Lugenbeal studied prehistoric archeology at Wisconsin before resigning from GRI citing "the emotionally and ethically debilitating attempt to bolster our peoples' faith by telling them a series of partial truths about science" (Numbers, 1993).

A very few young evangelicals did manage to survive graduate education in geology with their Biblical fundamentalist faith intact. Three of the most prominent are Stephen Austin, John Morris, and Kurt Wise (no relation).

Steven Austin earned a B.S. in geology form the University of Washington and an M.S. from San Jose State with a thesis critical of uniformitarianism. Morris and the CRS paid Austin's tuition and living expenses while he earned a Ph.D. in coal geology from Penn State in 1979 (Numbers, 1993). During his Penn State time he also wrote creationist articles under the pseudonym of Stuart Nevins. Currently he is chair of the ICR's Department of Geology and a major contributor to their in-house publications and articles on geology. His Grand Canyon: Monument to Catastrophe, (Austin, 1994) is a slick, full-color volume designed both as a guide for Austin's fundamentalist field trips into the Canyon (Figure 3) and as a potential text for fundamentalist college-level geology courses. In these publications his scientific philosophy is never in doubt: "The real battle in regard to understanding the Grand Canyon is founded not just upon Creation and Noah's Flood versus evolution, but upon Christianity versus humanism." (Austin, 1994)

Figure 3 (GIF, 268K)

Figure 3. Grand Canyon geology --- the sweeping history of earth told in rock that has inspired generation of geologists --- has recently been rewritten by creationists. In the alternative view the canyon was not formed by layers of sedimentation atop ancient metamorphic rock deposited over millions of years, followed by volcanic flows into the canyon and the downcutting action of the powerful Colorado River. Some 500 million years of the canyon's history are explained in this view (labels at left) as taking place during the Noachian flood year, a feat that would require massive layers of wet sediments to be deposited and harden at astounding rates over the course of weeks, leaving them solid enough to be incised into mile-high cliffs by receding floodwaters. (Creationist ages, left, after Austin 1994, with basic geology after Coney 1975.)

John Morris, Henry's son, earned a Ph.D. in geological engineering from the University of Oklahoma and taught there for several years. In 1984 he moved to the ICR where he is now Administrative Vice President. He has led several expeditions in search of Noah's ark and has worked on the supposed coexistence of human and dinosaur tracks in the Paluxy River bed of Texas. His book, The Young Earth (J. Morris, 1994), has an initial 35 pages which might just as well be the lesson book for a fundamentalist Sunday school. This is followed by about 75 pages of a mixture of geologic interpretation and Biblical themes. The final 70 pages are view-graph masters designed to "be shared with your church or Bible study groups." His overriding values seem clear. "The data of geology, in our view, should be interpreted in light of the Scripture, rather than distorting Scripture to accommodate current geological philosophy." (Morris and Morris, 1989)

Kurt Wise was raised in a fundamentalist Baptist family in rural Illinois and accepted flood geology as a teenager while attending a conference for Christian youth run by Bob Jones University. He graduated from University of Chicago with honors in geophysical sciences before going on to Harvard and his Ph.D. with Stephen J. Gould. He has been the focus of a number of articles in the popular press (Campbell and Scroggins, 1995, and Hitt, 1996) and currently teaches at the fundamentalist William Jennings Bryan College in Tennessee near the site of the Scopes trial. He minces no words about his scientific philosophy and agenda. "I intend to replace the evolutionary tree with the creationist orchard, separately created, separately planted by God." (Hitt, 1996)

Creationist Geologic Thought at Present

Until recently "Creation Science," as presented by the likes of Henry Morris and Duane Gish, was such a hodge-podge of geologic ideas, floating loosely in time and space, that it was nearly impossible to obtain an overall picture of how their Bible-based model might fit into the fabric of generally accepted geologic and paleontologic observations. This has changed or at least been modernized with the rising influence in ICR circles of the likes of Austin, Morris, and Wise. All three are familiar with some of the geologic literature but are highly selective about which portions they decide to use. They also tend to lean more heavily on ICR in-house publications than on refereed papers in the general literature.

The current thinking of the young creationist geologists is perhaps best shown in a paper co-authored by six of them, including Austin, Morris, and Wise (Austin et al., 1994). Their "tentative" model of "Catastrophic Plate Tectonics: A Global Flood Model of Earth History" starts about 6,000 years ago with a pre-flood earth differentiated into core, mantle, and a crust with horizontal segregation into granitic continents and basaltic ocean basins. "If this differentiation had occurred by any natural means, the gravitational energy released ... would produce enough heat to melt the earth's crust and vaporize the earth's oceans. ...it most certainly occurred before the creation of organisms (at the latest Day 3 of the creation week.)" The authors note that "even though such differentiation could have been performed by God without the 'natural' release of gravitational potential energy" the differentiation process provides a natural driving mechanism for the proposed next stages of rapid motion, the Noachian flood. This was initiated as slabs of oceanic floor broke loose and subducted along the edges of continents. Deformation of the mantle by these slabs raised the temperature and lowered its viscosity into a runaway convection system which overturned the whole mantle. Upwelling mantle plumes created the mid-oceanic ridges, drove plate tectonics at rates of "meters per second," and discharged magmatic steam into the atmosphere to cause the flood. Tidal waves washed the continents and piled marine sediments into great mountain systems along the edges. In a few hundred years after the flood, residual heat from the cooling ocean floor warmed the oceans and climate into a system characterized by efficient atmospheric transport of moisture to the poles to create glaciation and ice caps.

The thermal problems of this model are mind boggling. At the start, gravitative energy released by earth's differentiation into core and mantle would raise average temperature of the entire globe by 2,500 degrees (Birch, 1965). To this must be added the frictional heating of the runaway subduction plus the massive heat of condensation of a collapsing vapor canopy. Then brand new basaltic ocean floors at minimum temperatures of 1,100 degrees C. had to form over 2/3 of the earth's surface, presumably beneath non-boiling flood waters. Finally this massive thermal pulse dissipated in a few thousand years by unstated processes to leave most of the earth's surface devoid of hot springs or abnormal heat flow. The authors apologize that their "model is still in the formative stages and thus is incomplete." From a thermal viewpoint "incomplete" seems like gross exaggeration. An incandescent earth with an asbestos ark floating on a sea of molten lava would be more appropriate!

The Creationist Geologic Time Scale

Austin's (1994) book in particular and to some extent Morris and Morris (1989) and J. Morris (1994) are not to be taken lightly. Before entering into confrontations with Creationists any scientist, even one with extensive geologic training, would be well advised to read these publications very carefully to see where and how the record is cleverly distorted or how obscure literature citations or in-house Creationist studies are expanded into general principles concerning a global flood. In reading such literature, a traditional geologist has difficulty keeping the time scale in order. Time and again, I found myself confusing pre- and post-flood events or mixing creation week events with flood events. One version (Froede, 1995) has a rudimentary scale with major eras being Creation Week, Antediluvian Ages, Flood Event, Ice Age, and Present. Another by Walker (1994) splits geologic time into eras and stages, based largely on numbers of days during creation week and the flood event. In order to minimize my confusion and get the overall Biblical chronological sequence in order, I found it necessary to go through conflicting ideas in many Creationist papers before being able to build my own version of their geologic column. Once this framework of Creationist geologic time was in place, many of their speculations could be added to other valid geologic observations which they generally ignore to produce Figure 1. Not included are items from even the lunatic fringe of Creationism such as the flat earth based on the Biblical description of its having "corners" (Flirpa, 1987) or a geocentric solar system harking back to pre-Copernican days (Schadewald, 1985) or Henry Morris' hollow earth. After a creation seminar on October 24, 1986, Morris was asked about the bottomless pit of Revelations 9:1-11. His answer was "Whenever Hades or Sheol is referred to in the Bible, it's always down in the earth, the depths of the earth. So right there in the center of the earth, apparently there's a great opening that we can't really deal with in terms of our seismic instruments or other instrumentation. But apparently it is there. You can take the Bible to mean what it says." (Creation/Evolution newsletter, 1986)

Creationists will undoubtedly challenge or try to confuse arguments concerning individual items on Figure 1. The detailed discussion that follows attempts to arm the scientific community with some real data and references and to warn of typical Creationist attacks on particular points. For additional geologic discussion, a scientist would be well advised to read Heaton's A young Grand Canyon ?, Weber's (1980) paper on "fatal flaws in flood geology" or Young's (1977, 1982) books which seem to have upset the Creationists enough to make them attempt to answer his points one by one (Morris and Morris, 1989) or Gish's (1993) book of rebuttals.

Creation Week (1)

The Biblical sequence of events of creation week is well known and discussed at length by H. Morris (1993) among a host of others. Some Creationists even highlight the discrepancy between the Genesis sequence of events and the traditional "evolutionary order of appearance." J. Morris (1994) gives the following comparisons which to his mind support the Biblical sequence but which a scientist might find an ideal place to begin application of logic.

. Biblical Order Evolutionary Order

Earth before sun and stars Sun and stars before Earth

First life forms are plants First life forms are marine organisms

Fruit trees before fish Fish before fruit trees

Fish before insects Insects before fish

Land vegetation before sun Sun before land plants

Birds before land reptiles Reptiles before birds

Man as the cause of death Death precedes man

The precise date of creation in years varies among Creationists. A good discussion of the origins of this date, starting with the Bishop of Ussher (1650), is given by Brice (1982). H. M. Morris (1993) suggests that creation took place about 6,000 years ago and that elapsed time from creation to the flood was 1,656 years. By subtraction, this means that the flood took place about 2350 B.C., a time somewhat after the start of recorded Egyptian and Summerian history. J. D. Morris (1994) notes that some uncertainties exist between the length of the Biblical time and the historical record but "I suspect it is the secular chronology which needs revision."

Garden of Eden (2)

The well known Genesis story is expanded at length by H. M. Morris (1993). Walker (1994) describes a 1700 year span as the "Lost-World Era" starting with the apple incident and expulsion from Eden and ending with the Flood about 2300 B.C. He suggests this name because "not much of geologic significance would have occurred in the time available." This "not much" would include almost all events in the rich record of Precambrian geology.

Canopy Theory (3)

Most creationist models for the source of the flood waters stem from the writings of Isaac Newton Vail who proposed (1874) and successively refined into the "annular theory" (Vail, 1912) a model in which the early earth had a series of Saturn-like aqueous rings, the progressive collapse of which caused successive cataclysms to bury and create fossils. Collapse of the last remnant ring caused the Noachian flood. Subsequently, most writings propose only one great canopy which collapses to create the flood (Dillow, 1981). Vardiman (1986a), head of the ICR physics department, calculates that the base of the canopy was about 7 km above the earth's surface with an ambient surface temperature of about 30 degrees C.. Additional unlikely details of this pre-flood atmosphere are calculated by Jorgensen (1990). Other Creationists writings such as the Austin et al. (1994) model avoid some of this problem by having much of the future flood water stored within the earth to burst forth as the "fountains of the deep" described in the Bible (Figure 4).

Figure 4 (GIF, 150K)

Figure 4. Catastrophic phenomena must be postulated to explain the occurrence of a flood powerful enough to drown all but a few creatures and to massively rearrange the surface of the earth. Creationists have suggested that before the Noachian flood the earth had a Venusian atmosphere dominated by a huge canopy of water vapor that collapsed and inundated the earth to create the flood with the help of "fountains of the deep" activated by the subduction of crustal plates. At the center of the earth in one creationist view, as yet undetected by seismology, is Hell.

Radiometric dating (4)

Creationists argue that radiometric dates are invalid on a number of grounds, despite the massive and detailed explanation of all the dating methods by Dalrymple (1991). They argue that if the speed of light is changing, then all other fundamental constants could have changed, including rates radioactive decay. Some of these arguments are based on supposed changes in the speed of light using uncertainties in such measurements as of about 20 years ago. More recent refinements in the measurements have laid this idea to rest for all but the most committed (see discussion by Schadewald, 1984, and Lippard, 1989, 1990).

Related creationist arguments note (correctly) that light from the most distant galaxies has red shifts up to the equivalent of four times the speed of light. Hence, they argue that the universe appears to be expanding at a rate in excess of the speed light in violation of Einstein's equations and that these values for the speed of light must have changed with time. Thus, a very young universe is possible (Curtis, 1995). The whole argument is based on a false premise, that these red shifts are Doppler effects. In reality, the red shifts have little to do with Doppler-like instantaneous speeds of celestial objects. Instead, they represent a kind of tape measure of the wavelengths of light stretching from those distant galaxies to the earth. When these wavelengths started, they were of normal lengths. In the intervening eons, the cosmos has expanded along the line of travel by as much as four times, stretching the wavelengths embedded in it. Thus, the Creationist argument is a complete misreading of the physics: the red shift has nothing to do with instantaneous Doppler effects and Einsteinian equations but instead is a measure of long term expansion of the cosmos and everything within it.

Another creationist argument claiming unreliability of radiometric dating is that of Gentry (1992), who observed tiny spheres or halos of radiation damage around minerals embedded in Precambrian micas. An excellent summary of Gentry, both as a person and a "scientist," is by Gardner (1989). Gentry argues that these halos had to be formed in primordial granites by some, now extinct, very short-lived, radioactive element during the first few minutes between neucleosynthesis and Earth formation. Because this contradicts geologic dating of Precambrian events, he argues all those dates must be wrong. His argument with its confused geology and the real geologic facts refuting it are put forth by Wakefield (1988) and Wakefield and Wilkerson (1990), who show that Gentry's samples came from dikes that cut Precambrian sedimentary rocks. Hence, his samples must be younger than those sedimentary events: there is no way the geologic setting allows them to be of primordial origin. In contrast, the best radiometric dates yield a primordial age of the earth and solar system by defining sequential events of accretion and early differentiation in meteorites ranging from 4.58 to 4.50 Ga (Allegre et al., 1995).

Creationists commonly cite the helium problem as evidence for a young atmosphere, contradicting the radiometric dates (Vardiman 1986b, 1990, and J. Morris, 1994). It is well known that the rate of production of helium from the earth's crust and mantle exceeds by a factor of 2 to 5 the Jeans rate of strictly thermal escape from the upper atmosphere (Kellogg and Wasserburg, 1990; Harper and Jacobsen, 1996). If these were the only factors in the earth's helium balance, the atmosphere might have a maximum age of only 2 ma. (J. Morris, 1994). However, Shizgal and Arkos (1996) provide a number of non-thermal processes capable of accounting for steady-state atmospheric compositions of earth, Venus, and Mars. These include exothermic exchanges of He+ and N2+ to boost He to escape velocity as well as the polar wind sweeping He+ outward along high-latitude open magnetic field lines. The helium problem is still under active scientific investigation, but it has gone far beyond the classic thermal escape models still cited by the Creationists.

Another frequently cited argument for the "unreliability" of radiometric dates is Austin's (1994) dating of the Uinkaret lava flows of the Grand Canyon region. It is generally recognized that some of these flows were so young that they cascaded over the Canyon edges and dammed huge lakes within it. Austin cites a number of different analyses of these lavas which can be used to calculate a wide range of radiometric model ages, some older than the earth itself. He concludes (p. 129) by asking: "Has any Grand Canyon rock ever been successfully dated?" The counter argument might be: "Why is your sundial not as accurate as my quartz crystal watch?" There are many methods of deriving radiometric dates, some are widely recognized as being far more accurate than others. For the most part, Austin used a ham-handed approach by dating whole rocks rather than individual minerals or parts of individual mineral grains. He then culled other dates from the literature for comparison to complain about the wide spread of all the results: a straw-man approach. In reality, there are quite precise dates on these Uinkaret volcanics, using some of the best K-Ar methods (Wenrich et al., 1995). These show a regional pattern of younger and younger dates moving eastward with time to reach the youngest of the Grand Canyon volcanos only 10,000 years ago, in good accord with the geomorphic data.

Creationist claims about radiometric dates coupled with the supposed unreliability of the fossil record fail to point out the rarity of locations where rocks with well controlled fossil dates are closely associated with proper mineral material for the most precise of radiometric dates. There are at most a few hundred of these well dated localities on which the entire dating system of the geologic column is based. Where such conditions exist, the same fossil horizons yield precise dates of the same fossil horizons even then the locations are continents apart. For instance, Bowring et al. (1993) use the finest uranium-lead methods to date zircons associated with the base of the Cambrian in Siberia at 543.9 (+/- 0.2) million years while in southern Africa, Grotzinger et al. (1995) find a number of ash beds spanning the same fossil range yielding dates from 545 to 539 (+/- 1) million years. In the Rocky Mountain region, about 20 Cretaceous ash beds are interlayered with well known fossil-bearing sequences recognized both here and in Europe. Precision dating of these ash beds by Obradovich (1993) confirms the same 1, 2, 3 .. sequence as do the fossils and field relationships for individual beds differing by only 0.5 to 1 million years.

In the face of such precision and reproducibility, it is difficult to argue that radiometric methods and the associated stratigraphy, when used with care on the best of geologic locations, have no reliability and that the fossil record is a rather haphazard jumble of life forms mashed together as the flotsam and jetsam of a single great flood.

Humans and Dinosaurs Coexisting (5)

Creationists (Gish, 1992, and Ham, 1993) use Biblical statements of the absence of death in Eden prior to the apple incident to conclude that all animals, including dinosaurs, were vegetarians at that time. Thus, they would claim that God created Tyranosaurus Rex to eat leaves with those teeth and peacefully share Eden with lions, humans, and the like.

The "evidence" most commonly cited for coexistence of pre-flood humans and dinosaurs is the exposure of footprints near Glen Rose in central Texas in the bed of the Paluxy River. In that these beds are interpreted as Noachian flood deposits, the tracks must have been made by the evil people of those days as well as the dinosaurs just before both groups were engulfed by the waters. Why the tracks are those of walking rather than running individuals is not explained.

To my knowledge, the best scientifically based discussion of these tracks is by G. J. Kuban (1986) who reports visiting the site in the company of a number of Creationists, including ICR's John Morris. Kuban's extensive documentation of the tracks includes stain markings of obviously non-human, three clawed toes as integral parts of the "man-tracks." He notes later correspondence with John Morris of ICR, including Morris' subsequent agreement that all the Taylor Site tracks (the best of the sites) were probably dinosaurian. In a following article of the same issue, J. Morris (1986) makes a half-hearted retraction.

Kuban's religious neutrality is shown in an after statement to his 1986 paper: "I am a Christian and believe in a Creator, but prefer not to be labeled a 'Creationist' or an 'Evolutionist,' since I do not fully identify with all the tenets that are often assumed to typify each camp. However, on some issues that I have studied in depth, such as the Paluxy controversy (Kuban also has published a 250 page monograph on the subject), I have formed definite conclusions. Although my findings are not favorable to the "man track" claims, the objective of my research has not been to attack Creationism, but to carefully investigate and document what actually exists on the Paluxy sites alleged to contain human footprints." Kuban notes that: "When the full evidence is brought to light, it is evident that all the Taylor Site tracks are dinosaurian."

Films for Christ Association, which made and distributed the film "Footprints in Stone" about these tracks, reviewed Kuban's evidence and showed its basic honesty by immediately withdrawing the film from distribution and giving a clear retraction (1986).

Despite all this evidence, even from within Creationist circles, the Paluxy footprints are certain to be raised again and again before scientifically unsophisticated audiences. For instance, Helfinstine and Roth (1994) have published a 109 page booklet on these tracks and artifacts. H&R are at best amateur geologists (R cites his credentials as four extension course in geology; H cites none at all), and at worst they have the bias of being past presidents of the Twin-Cities Creation Science Association. They continue the claim of human footprints as well as the existence of a "human finger" of ante-deluvian man with photos looking remarkably like a geologic concretion. They also illustrate a "pre-flood" hammer embedded in iron oxide in a setting looking like a typical bog iron deposit, a process which is still going on today and could easily surround a 19th century hammer. Interestingly, their list of acknowledgments does not include ICR's John Morris who wrote a book on the tracks nor Glen Kuban with his thorough scientific studies on the site.

Human Life Spans of 900 Years (6)

H. Morris (1993) noting Noah's list of the various human generations and their times of death (Genesis 5 and 6), concludes that "one of the most remarkable aspects of Noah's record is the great longevity of the antediluvian patriarchs. The average life span of those recorded - except for Enoch - was 913 years." Tables showing all the ages and calculations were published by Lightfoot in 1647 and are reproduced by Brice (1982). Vardiman (1986a) proposes that shielding from cosmic radiation by the pre-flood atmospheric water canopy was the cause for human longevity. According to the Vardiman model, Dillow's (1981) graph showing a nearly linear decrease in life span in the twelve generations following Noah at 950 years to Jacob at 147 years, was the result of progressively increasing radiation exposure once the atmospheric canopy had cleared to produce the flood.

Lunar Craters (7)

Lunar craters are interpreted by Morris (1978) as the result of a cosmic battle between Satan's angels and those of the Archangel Michael (Figure 2). NASA has not yet accepted this model. In addition Creationists allege that lack of thick dust on the moon and it its craters indicates a young earth. This argument continues to be made despite a recent Creationist technical paper (Snelling and Rush, 1993) which reviews the subject and concludes:

"It thus appears that the amount of meteoritic dust and meteorite debris in the lunar regolith and surface dust layer, even taking into account the postulated early intense bombardment, does not contradict the evolutionists' multi-billion year time scale (while not proving it). Unfortunately, counter responses by creationists have so far failed because of spurious arguments or faulty calculations. Thus, until new evidence is forthcoming, creationists should not continue to use the dust on the moon as evidence against an old age for the moon and solar system.

Fossil Stratigraphic Sequence (8)

The geologic record is clear in showing more and more complex life forms at progressively higher levels. Creationists argue that this represents more and more complex animals running to the mountain tops to be washed off and buried last (Figure 5), a mechanism proposed early in this century by George McCready Price in many papers and in his textbook, the New Geology (1923). Excellent summaries of Price and his ideas are given by Gardner (1986) and Numbers (1982). This mammals-to-the-mountain tops model is still in vogue in Creationist circles although some more recent variations have included rising waters engulfing first the shoreline plant and animal communities and then the upland flora and fauna. The argument somehow neglects to discuss why the burial sequence for fish, marine reptiles, and marine mammals followed the same pattern of increasing complexity when these groups should not have been so severely affected by rising waters. In addition, looking at the distribution of intelligence in today's humans, a pre-flood human race without a single individual dumb enough to be trapped on some isolated mountain top in early stages of the rising flood waters would seem to be a miracle in its own right.

Figure 5 (GIF, 108K)

Figure 5. "Creation science" explains the fossil record and deposits of petroleum, natural gas, and coal as products of the flood year. Larger land animals, it is argued, ran to the mountaintops (upper insert), explaining why they appear in upper fossil strata; meanwhile massive mats of vegetation formed (lower insert), later to become coal beds. The volcano that is now Mount Ararat rose rapidly (bottom right) beneath the deluge and just as rapidly cooled to provide a place for Noah's ark to later be grounded. According to this view, human beings and dinosaurs co-existed before the flood. At lower left, water spews from one of the Biblical "fountains of the deep."

Above all, the creationist arguments implies that the fossil record is a somewhat haphazard jumble of odds and ends dumped by the flood and represents only a general sequence of simple to complex life. They commonly argue that the geologic rock record and its fossil sequence is a vast conspiracy among pointy-headed academics who warp and misinterpret the evidence in an attempt to defend cherish beliefs about a science's particular version of the nature of the earth. Another group beside the scientific community has vested interests in the problem. Oil companies spend billions of dollars every year based on the belief that the earth contains a highly ordered and very predictable fossil record. Each year they test and refine the details of this fossil sequence to locate ancient reefs, trace the shorelines of long vanished oceans, and unravel the complex time relationships of ancient mountain systems. These fossil data control the drilling of thousands of multi-million dollar wells, guiding the drill bits to precise geologic targets at depths up to 8 km. One might expand the Creationist charges about pointy-headed academics to ask who is likely to be more reliable about hard facts concerning the nature of the earth: (1) a group of religious advocates most of whom have almost no direct knowledge of the earth but wish to push their particular theology about the Bible or (2) numerous hard-headed petroleum businessmen who have been drilling that earth on a day-to-day basis for over a century and every day pour millions more of their own dollars into ventures based on that experience with the fossils and the geologic record?

Coral Reefs and Limestone Deposits Grown During the "Flood" (9)

The thick limestone and dolomite formations which cover large portions of the interior of North America to depths on the order of a km or more, pose especially difficult problems for the "young earthers." In that these huge deposits are composed dominantly of former calcareous muds and fossil debris from lime secreting organisms, their production during a single "flood year" would seem to require almost Herculean activity on the part of those organisms. For instance, in the Grand Canyon region the Redwall and Kaibab limestone formations are each about 150 m thick. If spread uniformly through the entire "flood year," these two units would require organisms to have produced carbonate mud at rates of about 80 cm per day!

Recently the "young earthers" have avoided this excessive growth rate during the "flood year" by a new twist (Austin et al., 1994). For about 1,500 years between Eden and the "flood," extremely abundant carbonates were produced by the vibrant biologic activity in the postulated extremely high carbon dioxide pressure of those times. Thick carbonate muds collected in those early ocean basins only to be hurled onto the continents by violent runaway subduction during the flood as plates moved at speeds 1 to 10 km per hour, depending on the model. Conceivably this process might yield the volume of carbonate sediments on the continents but hardly the delicate and orderly succession of fossiliferous limestone and other formations of the continental interior, the Grand Canyon, and elsewhere.

Coral reefs as opposed to regular limestone deposits pose an even more difficult problem because even an unsophisticated public has some idea of typical growth rates of corals. One "young earth" approach is by omission. Austin (1994) notes (correctly) that no great coral reefs occur in the Grand Canyon and, hence, pose no problems there. He fails to mention that the Permian Kaibab limestone of the Canyon has well known and generally equivalent units in the Permian Basin of West Texas (Frenzel et al., 1988). These include the famous Capitan Reef, reaching a maximum thickness of 610 meters (King, 1948) with well exposed forereef and backreef facies, all developed on the edges of the deepwater Permian Basin. Similar integrated reefs and adjacent basin systems can be found for the Silurian of the mid-continent region (Fisher et al., 1988) and the petroleum rich reefs of the Devonian of Alberta (Johnson and McMillan, 1993).

Elsewhere, Morris and Morris (1989) argue correctly but somewhat disingenuously that "coral" reefs of the past are probably not reefs at all. They cite S. E. Nevins (pseudonym of S. Austin, 1975) that one of the greatest of these, El Capitan and the Permian "reef complex" of West Texas, comprises mostly transported fossil-bearing lime muds. However, they state that this complex had a "real topographic expression ...that... controlled the distribution and character of sediments and organisms in the region." To most geologists this is the definition of a reef whether it is 100 % coral or not. No matter what one calls them, these are organic deposits which grew in place and were buried in their own debris. In the case of the Capitan Reef, the "flood" model would require an absolute minimum vertical growth rate for the mass of 1.6 meters per day or 7 cm per hour, a rate 80,000 times the maximum ever observed for a modern reef surface (Chave et al.,1972)!

Coal Deposits (10)

Coal beds represent compaction of organic materials to 5 to 10 percent of their original thickness. Hence, a typical coal bed might represent an original vegetational debris accumulation of 20 - 30 meters. Austin did his doctoral dissertation (1979) on a single coal bed in Kentucky. He argues that relationships in that bed suggest formation from a mat of floating vegetation, one of the half dozen or so methods of collecting organic layers to produce coal. Subsequently, with Ph.D. safely in hand, he added the interpretation that this floating mat was rafted in a part of Noah's flood accumulation (Figure 5). The implication is that all coal beds formed in this way. For some small coal beds, such mat accumulations are quite reasonable. For others, like the Pittsburgh and Kittaning coals of Pennsylvania and West Virginia, the total area of the original swamp had to be on the order of 20,000 square kilometers with systematic and continuous upward transition from underlying sands and lake beds into the swamp deposit (Wise et al., 1991, and references therein). There is no obvious regional discontinuity to represent the base of any floating mat nor can one imagine a 20,000 square kilometer floating mat avoiding breakup into smaller fragments in the tumultuous seas of the Creationists' flood. Again, the Creationists approach to this Kentucky coal is a case of taking one local example and extrapolating it to the entire geologic record (Major, 1990).

Thick Salt Beds (11)

Thick salt beds formed by evaporation of sea water are a common feature of geologic columns in many parts of the world. The "young earth geologists" interpret almost all classic stratigraphic units as deposits produced during the flood year: hence, they must also account for interbedded salt formations as part of those events (Figure 6). Some of the more extensive salt formations with the U.S. are in the Jurassic of the Gulf Coast (Worrall and Snelson, 1989), the Silurian of the New York to Chicago region (Alling and Briggs, 1961; Smosna and Patchen, 1978), and the Permian of the Paradox Basin of Utah (Baars and Stevenson, 1982). In the center of the Paradox Basin these salts reach a depositional thickness of 1.5 km (Rocky Mountain Association of Geologists Atlas, 1972) with at least 29 separate cycles of salt deposition (Hite, 1960). To deposit just these beds in a single year would require the salt to form at an average rate of 4 meters per day (17 cm per hour or 2.8 mm per minute) - and this by evaporation during a world-wide flood event!

Figure 6 (GIF, 150K)

Figure 6. Flood geology must explain a massive geologic record as a single year's events. The maximum known thicknesses of sedimentary rocks of a given age are plotted at top to derive their maximum rate of deposition during geologic periods, according to radiometric dating (graph adapted from Hudson, 1964). In the chart are listed some selected features in each geologic time segment that creationist models require to have been formed within part of the year of the Noachian flood, most in a few weeks. Standard geologic interpretations require any single one of them to occupy more than the total 6,000 years of earth history allowed by creationists.

For such deposits Creationists use an ostrich approach. The chemical balance of salt in the ocean is discussed by Austin and Humphreys (1991) and J. D. Morris (1994) with brief paragraphs on each of 11 ways that salt can be added and 7 ways it can be removed. The fourth of these removal methods is by halite (salt) deposition which occurs "as a result of river water evaporation, not sea water. This happens infrequently in trapped pools, but such deposits redissolve easily. This output is trivial. The volume of salt water evaporated in trapped lagoons and not redissolved is not significant." Numerical values for each of these input and output rates are given by Morris but with no units quoted to yield an absolute maximum age of 62 ma. for the oceans. He suggests that the real age is much, much less.

Nowhere is mention given of the enormous halite deposits of the geologic record nor of their generally accepted origin by continuous evaporation of sea water flowing into semi-restricted basins. Morris, in an earlier publication (Morris and Morris, 1989), argues that ancient "pure" salt deposits are not even evaporites because they are so unlike the "dirty" salt deposits forming today. He cites the Russian Sozansky (1973) that great salt deposits are derived from volcanic rocks as products of degassification of the earth's interior brought up by juvenile waters moving along faults. The deceptive statement quoted above about evaporation in trapped lagoons is at best only partly true and even that is obtained by tightly restricting the definition of lagoon. It is difficult to believe that while almost every elementary geology student learns about these great deposits of marine salts, a Ph.D. in geology (Austin) and another in geophysics (Morris) somehow managed to gain their advanced degrees while remaining innocent of any knowledge of such marine evaporative processes and geologic formations.

Sedimentary Cover of Continents (12)

Typical continents have a "granitic" basement with a cover of relatively flat lying Cambrian and younger sedimentary rocks with thicknesses on the order of a km (Sloss, 1988). Austin (1994) interprets all the traditional Cambrian (540 ma.) through Cretaceous (65 ma.) sedimentary rocks as part of the flood deposits. He labels the early Cenozoic (60 ma.) rocks of the Bryce Canyon area as "post-flood." I am uncertain of the dates he would place on the post-Cretaceous Cenozoic coastal plain and continental shelf deposits, some of which reach thicknesses of 12 km off the Mississippi Delta, but suspect that he would include most of these as "flood-year" deposits or, alternatively, as pre-flood marine deposits washed onto the continents during the flood. The flat lying and relatively undisturbed nature of these deposits argues strongly against such dumping models of pre-flood sediments.

Continental Drift (13)

H. Morris (1993) wants to open the ocean basins during later parts of the flood as a means of draining the waters from the continents. (For an alternate Creationist model see note #19, below.) In effect, the Morris model represents a form of continental drift and plate tectonics. If this opening occurred during the last half of the flood year with the east coast of the U.S. moving away from Africa by a total of 5,500 km, this would represent an opening rate of the Atlantic of 30 km per day or more than one km per hour.

A Creationist mechanism proposed by Baumgardner (1990) suggests that sudden subduction of the ocean floor caused steam and global rain for 40 days. Frictional heating of the downgoing slabs reduced the viscosity of the earth's mantle by a "factor of a billion" (from viscosity of rock to that of Jello). The result was a runaway convection system with the plates moving at high speed across the earth's surface. The fact that Baumgardner can write a finite element program to show convection motion proves nothing except that some form of mathematics can be applied to almost any set of assumptions, an excellent example of "garbage in, garbage out."

Deep Sea Sediments (14)

The "standard" oceanic columns have about 800 meters of deep sea sediments covering 6.45 km of oceanic crust (Worzel, 1974). Present day rates of accumulation of these sediments on the deep ocean floors for muds, calcareous ooze, siliceous ooze, and red clay of the North Pacific are respectively 0.2, .02, .005, and .001 mm/yr (Berger, 1974). Assuming a deposition rate of .01 mm/yr, the 800 m average accumulation would require 80 ma., a quite reasonable geologic value for average age of the ocean basins.

The "young earth" models would require all this accumulation to take place late in the flood year or during the subsequent 4,500 years, a rate averaging about 20 cm/yr or about 20,000 times that of the present. Above all, the sedimentology of very fine grained oozes and muds on the deep sea floor demands extremely slow sedimentation rates rather than the catastrophic dumping indicated by the flood model.

Hawaiian volcanos (15)

The largest of the Hawaiian islands is a complex of five volcanos built on the sea floor across deep sea sediments which presumably were deposited after the ocean basins opened during middle or later parts of the flood (H. Morris, 1993). Counting its underwater portion, this 30,000 foot high volcanic pile had to grow, cool, and somehow get populated with organisms rapidly migrating from Mt. Ararat, all in the last 4,500 years.

Mt. Ararat (16)

Mt. Ararat is also a volcanic peak reaching 5.2 km built on top of deformed sedimentary rocks. In the chronology of "flood geology" this geometry requires Ararat's top of 2 km of volcanic growth to have occurred entirely under water across deformed flood sediments very late in the flood year. Surprisingly the Bible does not report any associated ash or volcanic activity of this major submarine eruption just beneath the ark. Then, to be available for the ark's landing, the volcano had to cool completely in a matter of months, somewhat in violation of the laws of thermal physics and observations of underwater lava flows of Hawaii. Finally, a tree grew at a truly remarkable rate in only a few weeks on the fresh volcanic soil in order for the dove to bring a branch back to Noah.

Claims of the discovery of Noah's ark in the Mt. Ararat region are reviewed by one of the few persons recently allowed into the Ararat region (Collins and Fasold, 1996). The "ark" claimed to be found by some is shown to be nothing more than a resistant bed in a doubly plunging synclinal fold. Technical discussion of some of the ark design problems are given by Shneour (1986).

Yellowstone Forests (17)

In the Lamar Valley of Yellowstone the fossil remains of somewhere between 10 and 27 successive forests are piled one on top of another separated by river and ash deposits (Dorf, 1964). Dorf counts tree rings on the petrified wood and concludes that at the time of their burial the oldest trees averaged about 200 years in age, a difficult fact for Creationists' interpretation of this stack of forests as the deposits of a single year. In early papers Fritz (1984 and references to older papers therein) argues that these forest layers are the result of log jams in successive mud flows from a volcanic flank and, hence, could have been formed in a single short-lived volcanic event. This single mud flow model was and is widely cited by Creationists as an explanation for the successive Yellowstone fossil forest layers, something like a Mt. St. Helens type of catastrophe.

Field evidence given by Yuretich (1984) showed that most of the Yellowstone fossil trees were still in a standing position and many were rooted in soil developed in place. In a discussion and reply by Yuretich, Fritz (1984) notes "Yuretich's observation of in situ stumps is compatible with my model ... of transportation of up to 15% of the upright stumps. Additional studies on stumps picked totest the critical points of the slight differences between our models should show complete agreement." In other words, the multiple levels are for the most part a series of mature forests where were successively buried in place largely by stream related processes. The Creationists cannot represent these as the deposits of a single catastrophic year.

A related Creationist argument is polystrata fossil trees, namely preservation of standing tree stumps many meters in height penetrating a number of strata. The claim is that average sedimentation rates from traditional geologic time scales would be too slow for such trees to be buried before they rotted. The difficult is in the word average in that many geologic deposits occur as a series of closely spaced flood or ash events with the next series separated in time by hundreds to thousands of years.

Grand Canyon Erosion (18)

In the Austin model (1994) the sedimentary rocks of the Grand Canyon were all deposited during the early part of the "flood-year," later to be incised into a canyon by the receding waters. The model requires the newly deposited rocks to become strong enough within a few months after deposition to stand as mile high cliffs in violation of all reasonable calculations from hydrology, soil mechanics, and strength of materials. Some rock types, for example, some limestones, become lithified soon after deposition, but most sandstones and shales require major loss of water, compaction, and/or chemical cement to become a strong rock, processes which involve significant amounts of time. This is especially true for very fine grained muds in which low permeability makes complete dewatering almost impossible in any short period of time. Simple loading of other materials on top will not do; trapped water in the muds would cause sudden liquifaction of the entire mass, a phenomenon known to hydraulic engineers as the "sudden draw down condition." Rapid drainage commonly results in collapse of oversteepened cut banks as flood swollen rivers subside. Mudstones in the young Grand Canyon model should have behaved in the same way but would have collapsed even more readily than canal and river banks considering Canyon cliff heights are measured not in meters but more than a thousand meters (Figure 4). In that Henry Morris has the credentials of a hydrologist and engineer, might one expect a proper answer to this problem?

Animal Dispersion from Ark (19)

In order to account for the present distribution of animals and humans, some creationists propose that continental drift took place about 100 years after the flood. After the Ark grounded, streams of animals and humans migrated (under divine guidance ?) to the ends of the global supercontinent, Pangea. Once drift began, they rode the continents to their present locations. Continental traffic jams at speeds up to one mile per hour produced collisional mountain systems like the Himalayas and Alps (Curtis, 1995). A different model by Woodmorapple (1990) has the virtue of avoiding almost all these problems by suggesting that the present distribution of plant and animal life was the result of "anthropomorphic transport" after the flood. The mental picture of aboriginal peoples keeping kangaroos in place in their canoes during An Australia voyage is intriguing.

Earth Stands Still (20)

Because of its absurdity, Creationists rarely mention the Biblical tale of Joshua keeping the sun from setting (Joshua 10:12-13) while the Israelites took vengeance on the Canaanite kings. Velikovsky (1950) proposed that a few thousand years ago a comet, later to become the planet Venus, was ejected from Jupiter to do a near miss of the earth, stopping the earth's rotation and the sun's apparent motion while Joshua directed the continuing battle. Just how the earth's rotation was restarted is never mentioned. Velikovsky has been so thoroughly debated and refuted that it seems pointless to restate all the arguments and his faulty data. Many of the arguments can be found in Goldsmith (1977), Bauer (1985), and Morrison and Chapman (1990).

However, Velikovsky's mechanisms look almost like good science when compared with recent statements by an authoritative Creationist. Henry Morris, in the (1995) says:

"Since the earth rotates on its axis, the sun could only be made to 'stand still' relative to earth by stopping earth's rotation." ... "This was surely a unique miracle, but not beyond the capabilities of the Creator of the sun and moon and planets. He started their motions,has maintained them through the ages, and is able to change them at will."

So much for a "scientific" approach to earth history and celestial mechanics.

Ice Age (21)

Removal of the greenhouse effect after canopy collapse produced one and only one ice age. The Austinet al. (1994) runaway subduction model includes several hundred years of much warmer oceans (!) heated by newly formed igneous sea floors over 2/3 of the globe. It proposes that warmer oceans heated the atmosphere and facilitated transport of moisture to the poles, thus initiating the ice age (singular). Cooling was enhanced by the increased albedo of the earth from all the volcanic ash produced during flood tectonics. Once the global sea floor and oceanic cooling was complete, the ice age ended at about 2000 - 2500 B.C., and our modern climatic pattern took over. Reasons for failure to boil the oceans and methods needed to cool all this mass in a few hundred years are not included in the model.

To explain the apparent record of multiple glaciations Oard (1990) argues for a very thin, post-flood ice cap which lasted only 700 years. Periodic surges at its lobes and edges produced local burial of slightly older tills, all of essentially the same age. He suggests that true interglacial deposits are almost non-existent, that they are hard to correlate, and that the soils on them are difficult to interpret. He also argues that some soils form rapidly in today's environment and that the immediate post-flood, ice-age atmosphere caused soil formation to proceed at even greater rates to produce the buried soils.

Real evidence for multiple glaciation is overwhelming. Older works on glacial geology (Flint, 1971; Wright and Frey, 1965) describe in great detail arguments for four great ice ages in the last two million or so years. This evidence includes well developed soil horizons and sub-tropical vegetation over-run by succeeding ice advances (Morrison and Wright, 1965). More recent works (Goudie, 1983; Wright, 1989; Dawson, 1992; Anderson and Borns, 1994) support these observations and further separate the four advances into about ten different advances. In addition, they give evidence of several other very much older glacial epochs, including some Precambrian ones which would have been "pre-flood."

Probably the best arguments for the magnitude of ice age time is the record from long cores taken through the ice caps of Greenland and Antarctica. Gish's outrageous statement (1992) that an armored dinosaur had been found in the ice of Antarctica might be taken as a Mesozoic age for the ice, but in reality the fossil was found in Mesozoic rocks of the Santa Marta formation (Weishampel, 1990). In the Antarctic ice, summer and winter bands can be counted back, year by year, to at least 30,000 years (Anderson and Borns, 1994) with overall core lengths indicating total time spans of several hundred thousand years. Dates from counting the annual layers in the cores can in turn be correlated with C14 dates from the CO2 contained in entrapped air bubbles, with C14 dates from tree ring correlations which can be counted and correlated back 12,000 years, with annual sediment layers from glacial lakes, with dates from the pollen records of climatic change in Europe and America, and with radiometric dates and rate of sedimentation dates on deep sea cores. Most of these dates can in turn be stitched together and mutually supported by paleomagnetic dates from other areas and dating techniques (summaries by Anderson and Borns, 1994). As new evidence is gained and dating techniques are refined, all these lines of converging evidence show increasing good correlations with the Malenkovich cycles, based on Newtonian celestial mechanics, an additional set of time determinations linked to modern astronomic measurements. To argue in the face of such massive and interlocking evidence that the entire span of the Ice Ages constituted only the last few thousand years must represent a supreme example of faith overcoming reason.

Cooling Rates (22)

Various mineral types in large granite bodies form at different temperatures and/or are able to trap daughter products of radioactive decay within them, starting at different cooling temperatures. Radiometric dating of when these different minerals passed through their retention temperatures allows determination of the cooling history and rates within the granite body. Pitcher (1993) provides a summary of such measurements which range from 30 to 250 degrees C. per million years, depending on size of body and depth of burial. Such values are in good accord with typical laws of thermal physics.

The "young earth" proponents may be most vulnerable on the subjects of cooling rates and thermal budgets. Laws of cooling and heat transfer are well established and found in almost any elementary physics text with values and applications to geologic examples provided in many geophysics texts (Turcotte and Schubert, 1982). In addition to the Creationists' proposed preposterous rates of cooling before and during the flood as cited above, batholiths and related bodies with tens of thousands of cubic kilometers of formerly high-temperature igneous rocks require massive heat dissipation since 2500 B. C. by mechanisms recorded neither by general history nor the Bible. Furthermore, these mechanisms must be so efficient that not even hot springs remain in most areas of the globe. The Creation Research Society seems overendowed with engineers; the scientific community should challenge them to at least attempt to provide mechanisms and numerical solutions for the massive thermal problems inherent in their models.

Present-day Plate Motions (23)

The last 30-40 years have seen plate tectonics grow from an intriguing theory loosely supported by some data from a few sub-disciplines of geology into a revolutionary paradigm supported by massive data arrays from the entire spectrum of the geosciences. Detailed plate motion directions and velocities with their passenger continents (DeMets et al., 1990) have been derived from combinations of geophysics, deep sea drilling, seafloor magnetic anomalies, and land based structural, geophysical, and sedimentological studies, the whole cemented by a time framework based on stratigraphic, paleontologic, and radiometric time scales. Recent satellite-based global positioning system measurements for 38 sites on the different plates show a 95% correlation with the plate tectonic model predictions (Larson et al., 1997). Only the Pacific and Nazca plates needed some readjustment to fit the model. Similar conclusions, using slightly different very long baseline precision measurements from satellite and space geodesy, were reached by Robaudo et al. (1993). Because long term velocity determinations must involve a geologic timescale, an average of 3.16 my for the Larson et al. data, these measurements represent one more test and validation of radiometric and paleontologic dating methods.

To argue that the early runaway subduction processes (Baumgardner, 1994; Austin et al., 1994) have ceased and that measured present day plate motions represent relaxation phenomena which just happen by chance to be a near perfect match with the rates derived from the supposedly invalid and rejected traditional geologic time scale requires complete abandonment of Occam's razor.

Present Day and Post-flood Coral Growth Rates (24)

Post-flood growth of coral reefs compounds the problem of "flood-year" growth of ancient reefs as discussed above in item #9. In the Bahamas Standard of California drilled 5.76 km through backreef carbonates (Meyerhoff and Hatten, 1974). The atolls of the Pacific arc the upward continuation of reefs growing on subsiding extinct volcanos. Drilling showed 1.26 km of shallow water limestone on Eniwetok (Ladd et al., 1953), 0.38 km of reef limestone on Midway (Ladd et al., 1970), and 0.78 km of shallow water limestone on Bikini (Emery et al., 1954). In that the underlying volcanos are all built across deep marine sediments, they must be "post-flood" in age with their coral caps representing the last 4,500 years. As isolated atolls, all the carbonate had to be derived from organic growth on the island. The maximum recorded rate of growth of 30 mm/yr of a single coral of Fiji and Eniwetok (Chave et al., 1972) could just about produce the drilled thickness on Eniwetok in the allowed 4,500 years. If the maximum known production rate for any part of a reef surface of about 7 mm/yr (Chave et al., 1972) could have been sustained for the reef surface as a whole, the Eniwetok limestone would require about 180,000 years to form.

The Creationist response to these figures is to propose that an excessive amount of carbon dioxide remained in the early post-flood atmosphere and that this produced phenomenal growth rates. Subsequently, the present-day atmosphere evolved and slowed rates to the modern measured values. They also claim that slow growing corals on modern reefs represent only a surface veneer of the last few thousand years over top of thick line muds from the Noachian flood (Morris and Morris, 1989), a discovery which might come as a surprise to those who have actually drilled modern reefs and found coral dating continuously form the present to about 50 m.y. in the Eocene (Ladd et al., 1953). The overall coral reef discussion in the cited references is typical of the ICR approach; a combination of omission, redefinition of terms, and misstatement of facts to provide support for their particular literal interpretation of the Bible.

Conclusions

Only now is the scientific community coming to recognize that while the battles against Creationism in the last decade may have been won in the courts, the war itself is in serious danger of being lost in the present court of public opinion and media nonsense. The warnings of the late Carl Sagan (1996) in "The Demon-haunted World" are a clear wake-up call for all of us. The statement by the American Geophysical Union (1994) is unambiguous: "The council of the AGU notes with concern the continuing efforts by Creationists for administrative, legislative and judicial actions designed to require or promote the teaching of Creationism as a scientific theory. The AGU is opposed to all efforts to require or promote the teaching of Creationism or any other religious tenets as science." Kraus (1996) may have made the best statement in a New York Times Op Ed piece: "The increasingly blatant nature of the nonsense uttered with impunity in public discourse is chilling. Our democratic society is imperiled as much by this as any other single threat, regardless of whether the origins of the nonsense are religious fanaticism, simple ignorance, or personal gain."

If such activities are to be opposed effectively, a first step is to learn the ideas, history, and underlying assumptions of their proponents. A second step is to devise an effective counter strategy. To date, the scientific community has been woefully inadequate in the Creationist battle on both counts. This paper is an attempt to focus our opposition, (1) by providing some readily accessible information on the Creationists, (2) by making a proposal for an offensive rather than defensive strategy, and (3) by giving some background facts to implement the strategy. In public forums, the Creationists should be challenged to defend their total model of earth history, difficulties and all, and to give their supporting "evidence" on an item-by-item basis. Again and again, we should force the point that extraordinary claims require extraordinary levels of proof. Such public confrontations with Creationists may have only the scientific depth of disputes between three-year olds, but at least the proposed strategy will force those fights to occur with their toys in their sandbox rather than ours.

6. The Treatment of Geological Time … the History of Life on Earth IN HIGH SCHOOL BIOLOGY TEXTBOOKS 

ARTICLE

The concept of evolution is fundamental to the study of modern biology. It is a key element of the National Science Education Standards (National Research Council, 1996) and is recognized as an essential component of the curriculum in position statements of the National Science Teachers Association and the National Association of Biology Teachers (see National Academy of Sciences, 1998). Since all of the definitions of evolution (e.g, "organic change over time" or "descent with modification") imply a temporal element, the presentation of evolution in the biology curriculum should include some sense of the timespan over which evolutionary events have occurred as well as an overview of the life forms at various points in geological time. In addition, the evidence that supports these claims and the reasoning processes that scientists use to study historical events should be a standard element in any presentation of the principles of scientific inquiry.

In spite of the importance of geological time in evolutionary biology, misconceptions about historical events in the history of life on Earth are common. For example, a recent survey by the National Science Foundation found that almost 50% of the general public believes that humans and dinosaurs coexisted (National Science Board, 2000). Misconceptions about geological time are also common in biology teachers. A survey of high school biology teachers in Indiana reported that 12.5% of respondents agreed or strongly agreed with the statement, "The age of the Earth is less than 20,000 years," while 15% accepted the statement, "With few exceptions organisms on Earth came into being at about the same time" (Rutledge & Warden, 2000). The same two statements received higher levels of support among high school biology teachers in Texas (Shankar & Skoog, 1993). Surveys and opinion polls like these suggest that ideas about geological time that the scientific community rejected long ago are durable elements of the public view of evolutionary biology.

Although there may be many explanations for the persistence of alternative conceptions about evolutionary time, the difficulty in comprehending the enormous time spans involved in Earth history must be among the most pervasive. Keown (1988) noted the lack of an accurate understanding in both students and adults of the vast spans of time over which evolutionary events occur. In a study of 10- and 11-year-old English schoolchildren, Trend (1998) found that students had a relative sense of time (e.g., "ancient" and "extremely ancient"), but they lacked a clear chronology of geologic events. Similarly, Marques and Thompson (1997) found that 14- and 15-year-old students did not distinguish between the origin of the universe and the origin of the Earth. The huge numbers involved in the geological timescale cause similar confusion among adults. In fact, teacher conceptions of geological time often include age estimates of 1 trillion years for events that are perceived to be "extremely ancient" (Trend, 2001). These observations reflect the abstract nature of "deep time" (see Gould, 1987) and suggest potential areas of difficulty as students attempt to reach a meaningful understanding of the enormity of geological time and the biological events that occurred across that time span.

Glenn (1990) has documented a decline from 1960 to 1989 in the amount of space devoted to the history of life in high school earth science textbooks, but we are aware of no similar study in biology textbooks. Given the overall reduction in evolution coverage in biology texts (Rosenthal, 1985), we might expect the treatment of historical aspects of evolutionary biology to be limited. In this article, we present the results of a survey of 11 high school biology textbooks in which the following questions were addressed:

To what extent do texts discuss the logical processes and historical inferences that support many of the claims relating to evolutionary biology?

How extensive is the coverage of geological time and the biological events that occurred at various points in the history of life on Earth?

What kinds of timelines or other graphic devices do textbooks use in their descriptions of evolutionary events?

Methods

We selected 11 widely used high school biology textbooks for this review (Table 1). All of these texts have publication dates of 1998 or later and several represent new or revised editions of earlier versions. Each text was independently examined by two of the authors for its treatment of geological time and the scientific study of historical events. We were interested in discussions of the use of inferences in making statements about historical events as well as any mention of geological time spans or specific eras and periods. We read the introductory chapters of each of the 11 texts (where scientific methods were typically presented) as well as any chapters that covered the history of life on Earth. If there were no specific chapters on this topic, we used the index to find any references to the benchmark events we selected for this analysis. For the purposes of this review, we selected events that are specifically noted in Teaching About Evolution and the Nature of Science (National Academy of Sciences, 1998), including the earliest evidence of life, the occurrence of substantial amounts of free oxygen gas in the atmosphere, the origin of eukaryotes, and the first appearance of multicellular organisms. Finally, the use of timelines and related graphic devices was noted.

Results

Methods of Historical Science

Scientific methods of studying nature are developed in all of the texts (usually in the first chapter), but this treatment is generally limited to experimental science. Some texts imply the existence of other methods of doing science, but few provide any specific examples. The Miller and Levine (2004) text includes a section titled, "When Experiments Are Not Possible," in which field studies and epidemiological studies are noted. Biggs et al. (2002) also note field studies as an alternative to the controlled conditions of laboratory experiments, and Johnson and Raven (2001) note the value of comparative studies. All of the texts describe the transition from observations to hypotheses, and most of them discuss the development of predictions that must be tested, but the clear implication in all of these presentations is that experiments are the only way to test hypotheses. While inferences are described or discussed in several texts (either explicitly or through the use of synonyms such as "conclusions" or "deductions"), few texts address the use of indirect observations to draw inferences about natural processes.

The BSCS text, Biology: A Human Approach, features an innovative presentation that uses constructivism to emphasize conceptual learning. The book begins with Earth history and explicitly treats historical inference in an activity called "Major Events in Earth's History." (The canonical presentation of experimental science does not appear until much later in this text.) Students create a timeline, order a set of biological events along the timeline, and use fossil evidence to assign dates to these events. The entire section emphasizes the use of fossils to support logical conclusions about historical events, thus establishing inference as a powerful interpretive tool in the study of nature.

Treatment of Geological Time

All of the textbooks include a presentation of Earth history and the evolution of life on Earth. In many cases, this material was consolidated in a single chapter, but some texts presented historical material in more than one chapter. All of the texts cover the nature of fossils and most of them include a discussion of the general principles of radiometric dating. The presentation of geological time varies, with some texts including eras and periods in tabular format while others use timelines to show both geological time and biological events. The tables typically focus on Phanerozoic time and identify the approximate dates of geological periods, but geological time before the Paleozoic era is usually identified as "Precambrian." In some cases, epochs are identified in the Tertiary and Quaternary. All of the tabular presentations emphasize the dates of the time periods and usually do not describe biological features.

Timelines (graphic displays of geological time with important biological events superimposed at appropriate intervals) are used in about half of the texts and range from unscaled artists' renderings in a single figure to a spectacular image that runs across the bottom of 11 pages of text (Johnson & Raven, 2001). While every timeline extends back to at least 3.5 billion years ago ("bya"), none of them is properly scaled to show the enormous reach of the "Precambrian." Biggs et al. (2002) is typical of the scaling problem in timelines: Although the text notes that the Precambrian accounts for 87% of Earth's history, the Precambrian is only 15% of the timeline in this text. In some cases, artistic license appears to have interfered with an accurate representation of scale. For example, the first page of the 11-page icon in Johnson and Raven (2001) represents over 1 billion years of time (with intervals of 250 million years) while the last page represents less than 100 million years and the intervals change from 10 million years to 500,000 years on the same page! Many texts use analogies to develop the vastness of Precambrian time (e.g., a calendar year or a 12- or 24-hour clock on which the history of life on Earth is cast), but these images are subverted by the impression given by the timelines. Starr (2000) and Johnson and Raven (2001) also include figures with a phylogeny superimposed on the timeline, but the Starr figure suggests that the divergence of eukaryotes from prokaryotes occurred at 3.5 bya, even though the text identifies this divergence at <2 bya.

Major Biological Events in the History of Life on Earth

In some cases, authors use equivocal or imprecise language in the presentation of benchmark events (e.g., "between 1.5 and 2 billion years ago" or "by about 2 billion years ago"). If less ambiguous information was found elsewhere in the text, those data were used in the analysis (Table 2). Ten of the 11 texts give the earliest date for prokaryotic cells as 3.5 bya.

Starr (2000) includes an extended discussion of prebiotic evolution (e.g., origin of metabolic agents and self-reproducing systems; the origin of membranes) that ends with the evolution of protocells at 3.8 bya. The accompanying figure identifies these as prokaryotic cells. Mader (2001) and Strauss and Lisowski (1998) make similar reference to protocells but they do not imply that protocells are prokaryotes. Several texts include photographs of microfossils from Western Australia that have been dated at roughly 3.5 bya (Schopf, 1999).

The next benchmark was the development of an oxygen-rich atmosphere. All of the texts identify oxygen-producing photosynthesis as the principal source of oxygen in the atmosphere and all of them note that long periods of time would be required for sufficient oxygen to accumulate in the atmosphere. Estimates of the time at which this occurred vary widely, but most estimates fall around 2.5 bya. Biggs et al. (2002) make reference to increased prokaryotic diversity at 2.8 bya and link this to an oxygen-rich atmosphere, while the BSCS texts make weak references to oxygen accumulating in the atmosphere "by about 2 bya." Miller and Levine (2004) note iron oxide deposits as evidence for the presence of substantial amounts of free oxygen gas in the environment, but they are the exception in citing evidence in support of claims about the dates of this event. (For example, Towle [1999] simply states that it took about a billion years for oxygen to accumulate to sufficient levels to fill the atmosphere.)

All of the texts make it clear that the earliest cells were prokaryotic, and most of them suggest an extended period of time before the first appearance of eukaryotic cells. The BSCS text, Biological Science: An Ecological Approach, does not provide a date for the origin of eukaryotic cells, and other texts are confusing about this date. For example, Starr (2000) writes, "Eukaryotic cells evolved in the Proterozoic, possibly before 1.2 billion years ago" (p. 297), but then provides a photo of a eukaryotic fossil from 1.4 bya on the very next page! The texts seldom provide evidence in support of their claims, but generally place the origin of eukaryotic cells between 1.4 and 1.8 bya. Johnson (1998) is the exception in noting larger cell size as evidence of eukaryotic form.

The final benchmark we selected was the origin of multicellularity. The BSCS text, Biology: A Human Approach, does not provide a date for this event, but it strongly implies that multicellularity accompanied the transition to terrestrial life (approximately 400 million years ago). The other texts place the event at variable points in the Precambrian. For example, Biggs et al. (2002) indicate, "By the end of the Precambrian, about 544 million years ago, multicellular eukaryotes, such as sponges and jellyfishes, filled the oceans" (p. 385), but they give no indication how much earlier in time the origin of multicellularity occurred. Several texts imply that the bizarre creatures of the Ediacaran fauna (roughly 550 million years ago) were the first multicellular organisms, but the texts are generally uniform in providing little evidence in support of their claims for the origin of multicellularity.

Discussion

The textbooks examined here emphasize experiments as the principal means of studying nature. It would be easy for a student to conclude that experimentation is the only way to test hypotheses and that the experimental method is the only legitimate approach to scientific questions. While it is certainly true that experimental science is a prominent feature of modern biology, there are many aspects of nature that do not lend themselves to experimental study and there are many biological disciplines that do not involve direct observation of phenomena. The National Science Education Standards note the variety of approaches to scientific understandings and this is often mentioned in these texts, but alternative approaches are seldom identified. Given the privileged treatment of experimental science in textbooks, it is not likely that many teachers will be able to present alternative ways of testing proposed explanations of natural phenomena. Singer et al. (2001) describe an important non-experimental technique in their presentation of the comparative method in phylogenetic studies, as do papers that emphasize classroom applications of bioinformatics (e.g., Maier, 2001). These studies move from systematic observations to hypotheses that can be tested against further observations. The use of inference to interpret these results is identical to the analysis of conclusions from experiments and is a powerful tool in the evaluation of non-empirical hypotheses.

The two BSCS texts present contrasting approaches to the scientific study of historical events. Biological Science: An Ecological Approach makes its principal presentation of historical science in a chapter titled, "Ecosystems of the Past." This includes a section with the heading, "Interpretations Are Based on Principles," but there are no principles identified in this section. In fact, the only principle of historical science that emerges in the entire chapter ("The Present Is the Key to the Past") comes 10 pages later in a different section. Biology: A Human Approach devotes Chapter 2 to the study of fossil hominids and an exploration of Earth's history and "deep time." This text explicitly deals with studies in which direct observations are not possible and it clearly develops the use of evidence to come to conclusions about unseen events. This is an essential step, especially if teachers must deal with the misconception that it is not possible to be scientific about the past. Cooper (2002) argues persuasively for including successful historical studies in textbooks to clearly present the range of scientific methods available to biologists, especially when the studies deal with subjects that have genetic and phylogenetic features that cannot be directly observed.

All of the texts include geological time in their treatment of the history of life on Earth and most of them describe the method for assigning dates to ancient events. All of the benchmark events we selected were described and additional events were often included (e.g., the origin of plants, the invasion of land), but the evidence in support of the dates of these events was not often included in the text. The date for the origin of multicellularity was quite variable and often imprecise, but the other benchmarks were in line with current thinking on this topic (e.g., Schopf, 1999; Knoll, 2003). The BSCS text, Biological Science: An Ecological Approach, was remarkable for including no Precambrian time in its geological time scale; in fact, none of the benchmark dates we selected were presented in this text.

All of the books indicate that multicellular life did not appear until late in the Precambrian era. Thus, the literal meaning of these texts makes it clear that most of the history of life on Earth was characterized by unicellular organisms. Nevertheless, the dominance of these organisms across geological time is marginalized and is easily overlooked. For example, Johnson (1998) devotes eight pages of text to the 500 million years of the Phanerozoic era but only three pages to the 3 billion years that came before it. The most extreme case is the BSCS text, Biology: A Human Approach, which is otherwise noteworthy for its presentation of a scientific approach to the study of historical events. Here, most of the text and activities are focused on geological events within the past 100 million years. While it is true that the Paleozoic and Mesozoic eras include a rich record of charismatic organisms and key innovations, the Precambrian era includes an enormous number of biologically significant events. In fact, these events provide a useful way to introduce fundamental biological concepts, as Alles (2001) has shown in a curriculum that explicitly treats the evolutionary development of significant biological processes (e.g., photosynthesis, aerobic metabolism, and sexual reproduction).

The vast amounts of time in the history of life on Earth are difficult to comprehend because they exceed the daily experience of students and teachers. Many of the texts reviewed here include activities that model the geological time scale using clothesline or adding machine tape or toilet paper. These are concrete experiences that can accurately depict the relative time periods and help students appreciate the magnitude of geological time. Additional activities are given in McComas (1990) and Hedeen (1997) and useful Web sites include the "Time Machine" lesson from the Evolution and the Nature of Science Institute (www.indiana.edu/&sim;ensiweb/lessons/time.mac.html) and the "deep time" lesson from the PBS program, "Evolution" (www.pbs.org/wgbh/evolution/change/deeptime). The National Council for Social Studies Curriculum Standards for Social Studies (1994) encourages the use of timelines to help students acquire information and to set historical events in relation to one another. Biology teachers should adopt this recommendation, as well, but we urge teachers and writers to include proper scale. Students can recall dates of historical events, but they often have difficulty in placing them in appropriate relationship to each other. For example, earth science students can learn important Phanerozoic dates but they don't recognize that these events are limited to the last 11% of Earth's history (Dodick & Orion, 2003). Timelines that truncate Precambrian time, or omit it altogether, will perpetuate these misconceptions and limit the student's understanding and appreciation of the great events of deep time. An accurate view of the geological time scale will enable biology teachers to reduce the number of misconceptions concerning the history of life on Earth.

7. A date for all people

EARTH SCIENCE

Cesare Emiliani has a few complaints about the Gregorian calendar used by much of the world. The split between B.C. and A.D., he says, confuses arithmetic computations because there is no zero year. While time moves in only one direction, year numbers grow larger going both forward and backward in time. What's more, the calendar defines time relative to an event that holds little meaning for non-Christians, who make up more than half the world's population, according to Emiliani, a geoscientist at the International Academy of Sciences in Palm Beach Gardens, Fla.

As a solution, he suggests pushing back the starting date of the calendar 10,000 years, making the current year 11,995. Such a revision would have the beginning of the calendar coincide with the start of the current geologic time period, the Holocene epoch. This time has important worldwide significance because it marks the end of the last ice age and the beginning of agriculture, says Emiliani, who organized a session of historians and scientists to discuss the idea.

The resetting requires only simple arithmetic: add 10,000 to all A.D. years and subtract all B.C. years from 10,001. After the turn of the century, people could adopt a shortcut by replacing the number 12,000 with an apostrophe. The year A.D. 2001 would then become '1.

Has the time arrived for calendar reform?

"There are great advantages for certain people, but there are no advantages for others," admits Emiliani, who has been pursuing the idea for several years.

Comparison of notable dates in the

present and propose calendars

Calendar

Event Present Proposed

Approximate start of Holocene 10,000 B.C. 1

Approximate founding of Jericho 7,000 B.C. 3,001

Founding of Rome 753 B.C. 9,248

Birth of Jesus 1 B.C. 10,000

Discovery of America A.D. 1492 11,492

Start of the next millennium A.D. 2001 12,001

8. Fall in the House of Ussher

THIS VIEW OF LIFE

How foolish was the archbishop's precise date for creation?

I am uncomfortable enough in a standard four-in-hand tie; pity the poor seventeenth-century businessmen and divines, so often depicted in their constraining neck ruffs. The formidable gentleman in the accompanying engraving commands the Latin title Jacobus Usserius, Archiepiscopus Armachanus, Totius Hiberniae Primas, or James Ussher, Archbishop of Armagh, and Primate of All Ireland. He is known to us today almost entirely in ridicule--as the man who fixed the time of creation at 4004 B.C., and even had the audacity to name the date and hour: October 23 at midday.

Let me begin with a personal gloss on the caption to this engraving, for my misreading embodies, in microcosm, the entire theme of this essay. I confess that I have always been greatly amused by the term primate, used in its ecclesiastical sense as "an archbishop ... holding the first place among the bishops of a province." My merriment must be shared by all zoologists, for primates, to us, arc monkeys and apes-members of the order Primates. Thus, when I see a man described as a "primate," I can't help thinking of a big gorilla. (Humans, of course, are also members of the order Primates, but zoologists, in using the term, almost always refer to nearly 200 other species of the group--that is, to lemurs, monkeys, and apes.)

But this amusement is silly, parochial, and misguided. The term comes from the Latin primas, meaning "chief" or "first." In the mid-eighteenth century, Linnaeus introduced the word to zoology as a designation for the "highest" order of mammals-the group including humans. But the ecclesiastical usage has an equally obvious claim to proper etymology and substantial precedence in usage (the Oxford English Dictionary traces this meaning to 1205). Thus, we zoologists are the usurpers, not the guardians of a standard. (I wonder if preachers laugh when they see the term in a zoological book and think of a baboon running about in a neck ruff.) In any case, the archbishop of Armagh is titular bead, hence primate, of the Anglo-Irish church, just as the archbishop of Canterbury is primate of all England.

This little tale mimics the forthcoming essay in miniature for two reasons:

I shall be defending Ussher's chronology as an honorable effort for its time and arguing that our usual ridicule only records a lamentable small-mindedness based on mistaken use of present criteria to judge a distant and different past--just as our current amusement in picturing a primate of the church as a garbed ape inverts the history of usage, for the zoological definition is derivative, and the ecclesiastical primary.

The mental picture of a prelate as a garbed ape reinforces the worst parochialism that scientists often invoke in interpreting their history--the notion that progress in knowledge arises from victory in battle between science and religion, with religion defined as unthinking allegiance to dogma and obedience to authority, and science as objective searching for truth.

James Ussher (1581-1656) lived through the most turbulent of English centuries. He was born in the midst of Elizabeth's reign and died under Cromwell (who gave him a state funeral in Westminster Abbey, despite Ussher's royalist sentiments and his previous support for the executed Charles 1). As a precocious scholar with a special aptitude for languages, Ussher entered Trinity College, Dublin, at its founding in 1594, when he was only thirteen years old. He was ordained a priest in 1601 and became a professor at Trinity (1607) and then vice chancellor on two occasions in 1614 and 1617. With his appointment as Archbishop of Armagh in 1625, he became head (or primate) of the Anglo-Irish church--a tough row to hoe in this preeminently Catholic land ("Romish" or "papist" as Ussher always said in the standard deprecations of his day). Ussher was vehement and unrelenting in his verbal assaults on Roman Catholicism (he wasn't too keen on Jews and other "infidels" either, but the issue rarely came up). His 1626 "Judgement of the Arch-Bishops and Bishops of Ireland" begins, for example:

The religion of the papists is superstitious and idolatrous;

their faith and doctrine erroneous and heretical; their church

... apostatical; to give them therefore a toleration, or to

consent that they may freely exercise their religion ... is

a grievous sin.

One may cringe at the words (and no one can take Ussher as a model of toleration), but he was, in fact, regarded as a force for moderation and compromise at a time of fierce invective (read Milton's anti-Catholic pamphlets sometime if you want to get a feel for the rhetoric of those troubled years). Despite his opinions, Ussher continued to espouse debate, discussion, and negotiation. He preached to Catholics and delighted in meeting their champions in formal disputations. His own words were harsh, but he believed in triumph by force of argument, not by banishment, fines, imprisonment, and executions. In fact, even the hagiographical biographies, written soon after Ussher's death, criticize him for lack of enthusiasm in the daily politics of ecclesiastical affairs and for general unwillingness to carry out policies of intolerance. He was a scholar by temperament and, at best, a desultory administrator. He was in England at the outbreak of the civil war in 1642 and never returned again to Ireland. He spent most of his last decade engaged in study and publication-including, in 1650, the source of his current infamy: Annales veteris testamenti, a prima mundi origine deducti, "Annals of the Old Testament, deduced from the first origin of the world."

Ussher became the symbol of ancient and benighted authoritarianism for a reason quite beyond his own intention. Starting about fifty years after his death, most editions of the "authorized," or King James, translation of the Bible began to carry his chronology in the thin column of annotations and cross-references usually placed between the two columns of text on each page. (The Gideon Society persisted in placing this edition in nearly every hotel room in America until about fifteen years ago; they now use a more modern translation and have omitted the column of annotations, including the chronology.) There, emblazoned on the first page of Genesis, stands the telltale date: 4004 B.C. Ussher's chronology therefore acquired an almost canonical status in English Bibles--hence his current infamy as a symbol of fundamentalism.

To this day, one can scarcely find a textbook in introductory geology that does not take a swipe at Ussher's date as the opening comment in an obligatory page or two on older concepts of the earth's age (before radioactive dating allowed us to get it right). Other worthies are praised for good tries in a scientific spirit (even if their ages are way off), but Ussher is excoriated for biblical idolatry and just plain foolishness. How could anyone look at a hill, a lake, or a rock pile and not know that the earth must be ancient?

One text discusses Ussher under the heading "Rule of Authority" and later proposals under "Advent of the Scientific Method." We learn--although the statement is absolute nonsense--that Ussher's "date of 4004 B.C. came to be venerated as much as the sacred text itself." Another text places Ussher under "Early Speculation" and later writers under "Scientific Approach." These authors tell us that Ussher's date of 4004 B.C. "thus was incorporated into the dogma of the Christian Church" (an odd comment, given the tradition of Catholics, and of many Protestants as well, for allegorical interpretation of the "days" of Genesis). They continue: "For more than a century thereafter it was considered heretical to assume more than 6,000 years for the formation of the earth. "

Even the verbs used to describe Ussher's efforts reek with disdain. In one text, Ussher "pronounced" his date; in a second, he "decreed" it; in a third, he "announced with great certainty that ... the world had been created in the year 4004 B.C. on the 26th of October at nine o'clock in the morning!" (Ussher actually said October 23 at noon--but I found three texts with the same error of October 26 at nine, so they must be copying from each other.) This third text then continues: "Ussher's judgment of the age of the earth was gospel for fully 200 years."

Many statements drip with satire. Yet another textbook--and this makes six, so I am not merely taking potshots at rare silliness--regards Ussher's work as a direct "reaction against the scientific explorations of the Renaissance." We then hear about "the pronouncement by Archbishop Ussher of Ireland in 1664 that the Earth was created at 9:00 A.M., October 26, 4004 B.C. (presumably Greenwich mean time!)" Well, Ussher was then eight years dead, and his date for the earth's origin is again misreported. (I'll pass on the feeble joke about Greenwich time, except to say that Ussher used the Julian calendar and that such issues hardly arose in an age before rapid travel made the times of different places a matter of importance.)

Needless to say, in combating the illiberality of this textbook tradition, I will not defend the substance of Ussher's conclusion--for one claim of the standard critique is undeniably justified: a 6,000-year-old earth did make a scientific geology impossible because any attempt to cram the empirical record of miles of strata and life's elaborate fossil history into such a moment requires a belief in miracles as causal agents.

Fair enough, but what sense can be made of blaming one age for impeding a much later system that worked by entirely different principles? To accuse Ussher of delaying the establishment of an empirical geology is much like blaming dinosaurs for holding back the later success of mammals. The proper criterion must be worthiness by honorable standards of one's own time. By this correct judgment, Ussher wins our respect just as dinosaurs now seem admirable and interesting in their own right (and not as imperfect harbingers of superior mammals in the inexorable progress of life). Models of inevitable progress, whether for the panorama of life or the history of ideas, are the enemy of sympathetic understanding, for they excoriate the past merely for being old (and therefore both primitive and benighted).

Of course Ussher could hardly have been more wrong about 4004 B.C., but his work was both honorable and interesting--therefore instructive for us today--for at least four reasons.

1. The excoriating textbook tradition depicts Ussher as a single misguided dose of darkness and dogma thrown into an otherwise more enlightened pot of knowledge--as if he alone, representing the church in an explicit rearguard action against science and scholarship, raised this issue to recapture lost ground. No idea about the state of chronological thinking in the seventeenth century could be more false.

Ussher represented the best of scholarship in his time. He was part of a substantial research tradition, a large community of intellectuals working toward a common goal under an accepted methodology--Ussher's shared "house" if you will pardon my irresistible title pun. Today we rightly reject a cardinal premise of that methodology--belief in biblical inerrancy--and we recognize that this false assumption allowed such a great error in estimating the age of the earth. But what intellectual phenomenon can be older, or more oft repeated, than the story of a large research program that impaled itself upon a false central assumption accepted by all practitioners? Do we regard all people who worked within such traditions as dishonorable fools? What of the scientists who assumed that continents were stable, that the hereditary material was protein, or that all other galaxies lay within the Milky Way? These false and abandoned efforts were pursued with passion by brilliant and honorable scientists. How many current efforts, now commanding millions of research dollars and the full attention of many of our best scientists, will later be exposed as full failures based on false premises?

The textbook writers do not know that attempts to establish a full chronology for all human history (not only to date the creation as a starting point) represented a major effort in seventeenth-century thought. These studies did not slavishly use the Bible, but tried to coordinate the records of all peoples. Moreover, the assumption of biblical inerrancy doesn't give you an immediate and dogmatic answer--for many alternative readings and texts of the Bible exist, and you must struggle to a basis for choice among them. As a primary example, different datings for key events are given in the Septuagint (or Greek Bible, first translated by the Jewish community of Egypt in the third to second centuries B.C. and still used by the Eastern churches) and in the standard Hebrew Bible favored by the Western churches.

Moreover, within assumptions of the methodology, this research tradition had considerable success. Even the extreme values were not very discordant--ranging from a minimum, for the creation of the earth, of 3761 B.C. in the Jewish calendar (still in use) to a maximum of just over 5500 B.C. for the Septuagint. Most calculators had reached a figure very close to Ussher's 4004. The Venerable Bede had estimated 3952 B.C. several centuries before, while J. J. Scaliger, the greatest scholar of the generation just before Ussher, had placed creation at 3950 B.C. Thus, Ussher's 4004 was neither idiosyncratic nor at all unusual; it was, in fact, a fairly conventional estimate developed within a large and active community of scholars. The textbook tradition of Ussher's unique benightedness arises from ignorance of this world, for only Ussher's name survived in the marginal annotations of modern Bibles.

2. The textbook detractors assume that Ussher's effort involved little more than adding up ages and dates given directly in the Old Testament--thus implying that his work was only an accountant's act of simple, thoughtless piety. Another textbook--we are now up to seven--states that Ussher's 4004 was "a date reconstructed from adding up the ages of people named in the lineages of the scripture." But even a cursory look at the Bible clearly shows that no such easy solution is available, even under the assumption of inerrancy. You can add the early times, from creation up to the reign of Solomon--for the requisite information is provided by an unbroken male lineage supplying the key datum of father's age at the birth of a first son. But this easy route cannot be carried forward into the several hundred years of the kingdom, from Solomon's reign to the destruction of the Temple and the Babylonian captivity--for here we are only given the lengths of rule for kings, and several frustrating ambiguities (including overlaps or co-regencies of a king and his successor) were widely acknowledged but not easily resolved. Finally, how can you use the Old Testament to reach the crucial birthday of Christ and thus connect the older narrative to the present? For the Old Testament stops in the period of Ezra and Nehemiah, the fifth century B.C. in Ussher's chronology.

James Barr explains the problems and complexities in an excellent article, "Why the World Was Created in 4004 B.C.: Archbishop Ussher and Biblical Chronology," (Bulletin of the John Rylands University Library of Manchester, vol. 67, pp. 575-608). He divides the chronological enterprise into three periods, each with characteristic problems, as mentioned above. You can add up during the first period (creation to Solomon), but which text do you use? The ages in the Septuagint* are substantially longer and add more than 1,000 years to the date of creation. Ussher solved this dilemma by using the Hebrew Bible and ignoring the alternatives.

In the second period, you really have to struggle to establish a coherent time line through the period of the kings. You feint and shift, try to correlate the dates given for the two kingdoms of Israel and Judah, then attempt to link in the few ages given for events other than beginnings and ends of reigns. The result, with luck and adjustment, is a coherent network of mutually supporting times.

For the third period of more than 400 years from Ezra and Nehemiah to the birth of Jesus you cannot use the Bible at all--for no information exists. Ussher and all other chronologists therefore tried to link a known event in the period of kings with a datable episode in another culture--and then to use the timetables of other peoples until another lateral feint could be made back into the New Testament. Ussher proceeded by correlating the death of the Chaldean king Nebuchadnezzar 11 with the thirty-seventh year of the exile of Jehoiachin (as stated in 2 Kings 25:27). (Nebuchadnezzar was, of course, prominent in Jewish history for conquering Jerusalem in 586 B.C. and deporting its prominent citizens--the so-called Babylonian captivity.) Ussher could then calculate through the Chaldean and the subsequent Persian records, eventually reaching the period of Roman rule and the birth of Jesus.

3. But where did Ussher get October 23, 4004? Surely, neither the Bible nor any other source gives a specific date, even if you can estimate the year. Was this date, at least, a bow to dogma, even if the rest of the chronology has more scholarly roots?

No, not dogma, but a different style of interpretive argument--one based on symbol and eschatology rather than on listed chronology. (You cannot label this style as dogma, if only because each point became a subject of lively disagreement and fierce debate among scholars. No resolution was ever obtained, so the church obviously imposed no answer ex cathedra.)

First of all, the date 4004 rests comfortably with the most important of chronological metaphors--the common comparison of the six days of God's creation with 6,000 years for the earth's potential duration: "But, beloved, be not ignorant of this one thing, that one day is with the Lord as a thousand years, and a thousand years as one day" (2 Peter 3:8). Under this widely accepted scheme, the earth was created 4,000 years before the birth of Christ and could endure as much as 2,000 years thereafter (a proposition soon to be tested empirically and, we all hope, roundly disproved!).

But why 4004 and not an even 4000 B.C.? By Ussher's time, chronologists had established an error in the B.C. to A.D. transition, for Herod died in 4 B. C.--and if he truly talked to the Magi, feared the star, and ordered the slaying of the innocents, then Jesus could not have been born after 4 B.C. (an oxymoronic statement, but acceptable as a testimony to increasing knowledge).

Thus, if Jesus was born in 4 B.C., eschatological tradition should fix the date of creation at 4004 B.C., without any need for complex, sequential calculation of genealogies. This situation must inspire a nasty suspicion that Ussher "knew" the necessity of 4004 B.C. right from the start and then jiggered the figures around to make everything come out right. Barr, of course, considers this possibility seriously but rejects it for two reasons. First, Ussher's chronology extends out to several volumes and 2,000 pages of text and seems carefully done, without substantial special pleading. Second, the death of Herod in 4 B.C. doesn't establish the birth of Jesus in the same year. Herod became king of Judea (Roman puppet would be more accurate) in 37 B.C.--and Jesus might have been born at other times in this thirty-three-year interval. Moreover, other traditions argued that the 4,000 years would run from creation to Christ's crucifixion, not to his birth--thus extending the possibilities to A.D. 33. By these flexibilities, creation could have been anywhere between 4037 B.C. (4,000 years to the beginning of Herod's reign) and 3967 B.C. (4,000 years to the Crucifixion). Four thousand four is in the right range, but certainly not ordained by symbolic tradition. You still have to calculate.

But what about October 23? Here, chronology cannot help. Many scholars, from the Venerable Bede to the great astronomer Johannes Kepler, argued for spring as an appropriate season for birth and the chosen time of Babylonian, Chaldean, and other ancient chronologies. Others, including Jerome, Josephus, and Ussher, favored fall, largely because the Jewish year began then, and Hebrew scriptures formed the basis of chronology.

Now an additional problem must be faced. The Jewish chronology is based on lunar months and therefore very hard to correlate with a standard solar calendar. Ussher, recognizing no basis for a firm calibration, therefore decided to establish creation as the first Sunday following the autumnal equinox. (Sunday was an obvious choice, for God created in six days and rested on the seventh, and the Jewish Sabbath comes on Saturday.)

But if creation occurred near the autumnal equinox, why October 23, more than a month from the current date? For this final piece of the puzzle, we need only recognize that Ussher was still using the old Julian (Roman) calendar. The Julian system was very similar to our own, but for one apparently tiny difference--it did not suppress leap years at the century boundaries. (Not everyone knows that our present system--which keeps more accurate time than the Julian--omits leap years at all century transitions not divisible by 400. Thus, 1700, 1800, and 1900 were not leap years, but 1600 was and 2000 will be.) This difference seems tiny, but errors accumulate over millennia. By 1582, the discrepancy had become sufficiently serious that Pope Gregory XIII proclaimed a reform and established the system that we still live by--called, in his honor, the Gregorian calendar. He dropped the ten days that had accumulated from the "extra" leap years at century boundaries in the Julian system (this was done by the clever device of allowing Friday, October 15, to follow Thursday, October 4, in 1582).

We now enter the religious tensions of the time. Recall Ussher's fulminations against popery, an attitude shared by his Anglican brethren in charge. The Gregorian reform smelled like a Romish plot, and Ussher's contemporaries would be damned if they would accept it. (England and the American colonies finally succumbed to rationality and instituted the Gregorian reform in 1752. This delay, by the way, is responsible for the ambiguity in George Washington's birth, sometimes given as February 11 and sometimes as February 22, 1732. He was born under the Julian calendar, and eleven days, rather than ten, had to be dropped by this later time.) In any case, if the Julian discrepancy accounted for ten extra days in the 1,600 or so years between its institution and the Gregorian reform, Ussher realized that the disparity would amount to just over thirty days for the additional time from 4004 B.C.--thus fixing the creation at October 23, rather than about two-thirds through September, as by our present calendar.

One final point. Why high noon on the day of creation? The inception of Genesis reads:

In the beginning God created the heaven and the earth. And

the earth was without form, and void; and darkness was upon

the face of the deep. And the spirit of God moved upon the

face of the waters. And God said, Let there be light....

Now you cannot have days without alternations of light and darkness, so Ussher began chronology with the creation of light, which he fixed, for no given reason, at high noon. He wrote, "In ipse primi diei medio creata est lux" (In the middle of the first day, light was created).

But what about the phrases in Genesis that precede the creation of light? Here is an old exegetical problem: does the text give an epitome of the whole process here, or does it say that God made matter before creating light? Ussher accepted the latter reading and argued that a creation of matter "without form and void" took place during the night before the creation of light. Thus, a precreation, a slipping of material into place, occurred on the night of October 22--yielding several "temporary hours" (Ussher's words) before the overt creation of light on October 23.

4. Ussher's chronology is a work within the generous and liberal tradition of humanistic scholarship, not a restrictive document written to impose authority. As Barr notes, Ussher's Annales presents a chronology for all human history (meaning Western history, for he knew no other well enough), from the creation--and you must remember that humans were made five days thereafter, so earthly history is, essentially, human history--to the fall of Jerusalem in A.D. 70. Barr writes:

It is a great mistake, therefore, to suppose that Ussher was

simply concerned with working out the date of creation: this

can be supposed only by those who have never looked into its

pages.... The Annales are an attempt at a comprehensive

chronological synthesis of all known historical knowledge,

biblical and classical.... Of its volume only perhaps one

sixth or less is biblical material.

Socrates told us to know ourselves, and no datum can be more important for humanism than an accurate chronology serving as a framework for the epic of our cultures, our strivings, our failures, and our hopes.

The figure of Ussher that begins this article comes from the only work of his that I own--a comprehensive catechism prepared for children and their families, entitled A body of divinity: or, the sum and substance of Christian religion. Catechisms may simplify, but they have the virtue of laying basic belief right on the line, without the hemming and hedging so intrinsic to academic texts.

I was delighted by Ussher's defense of his chronology in this catechism--simple words that illustrate the basic humanism of his enterprise. How do we know about creation, he asks--and responds: "Not only by the plain and manifold testimonies of Holy Scripture, but also by light of reason well directed." His main quarrel, we note, is not with other timings of the human epic, but with Aristotle's ahistorical notion of eternity. "What say you then to Aristotle, accounted of so many the Prince of Philosophers; who laboreth to prove that the world is eternal." Ussher answers his own question by defending God's majesty against a mere unmoved mover of eternal matter, for Aristotle "spoileth God of the glory of his Creation, but also assigneth him to no higher office than is the moving of the spheres, whereunto he bindeth him more like to a servant than a lord."

I close with a final plea for judging people by their own criteria, not by later standards that they couldn't possibly know or assess. We castigate Ussher for making the creation so short--a mere six days, where we reckon billions for evolution. But Ussher fears that six days might seem too long in the opinion of his contemporaries, for why should God, who could do all in an instant, so spread out his work? "Why was he creating so long, seeing he could have perfected all the creatures at once and in a moment?" Ussher gives a list of answers, but one caught my attention both for its charm and for its incisive statement about the need for sequential order in teaching--as good a rationale as one could ever devise for working out a chronology in the first place! "To teach us the better to understand their workmanship; even as a man which will teach a child in the frame of a letter, will first teach him one line of the letter, and not the whole letter together."

9. LINNAEUS'S LUCK?

Section:

THIS VIEW OF LIFE

Why does the great creationist's system of classification work in Darwin's world? And what does the resolution of this paradox teach us about the importance and fascination of taxonomy?

Carolus Linnaeus (1707-78), the founder of modern taxonomy, frequently cited an ancient motto to epitomize his view of life: Natura non facit saltum (Nature does not make leaps). Such unbroken continuity may rule in the material world, but our human passion for order and clear distinction leads us to designate certain moments or events as "official" beginnings for something discrete and new. Thus, the signatures on a document define the birth of a nation on July 4, 1776, and the easily remembered eleventh hour of the eleventh day of the eleventh month (November 11, 1918) marks the armistice in a horrible war supposedly fought to end all contemplation of future wars. In a small irony of history, our apostle of natural continuity also became the author and guardian of a symbolic leap to novelty, for the modern taxonomy of animals officially began with the publication of the definitive tenth edition of Linnaeus's Systema Naturae in 1758.

The current classification of animals may boast such a formally recognized inauguration, but an agreement about beginnings does not guarantee a consensus about importance. In fact, the worth assigned to taxonomy by great scientists has spanned the full range of conceivable evaluations. When Lord Rutherford, the great British physicist (born in New Zealand), discovered that the dates of radioactive decay could establish the true age of Earth (billions rather than millions of years), he scorned the opposition of paleontologists by branding their taxonomic labors in classifying fossils as the lowest form of purely descriptive activity, a style of research barely meriting the name "science." Taxonomy, he fumed, could claim no more intellectual depth than "stamp collecting"--an old canard that makes me bristle from two sides of my being: as a present paleontologist and a former philatelist!

Rutherford's anathema dates to the first decade of the twentieth century. Interestingly, when Luis Alvarez, a physicist of similar distinction, became equally enraged by some paleontologists during the last decade of the twentieth century, he invoked the same image in denigration: "They're not very good scientists; they're just stamp collectors." I continue to reject both the metaphor and the damning of all for the stodginess of a majority, for Alvarez had exploded in frustration at the strong biases that initially led most paleontologists to dismiss, without fair consideration, his apparently correct conclusion that the impact of a large extraterrestrial body triggered the mass extinction of dinosaurs and about 50 percent of marine animal species 65 million years ago.

The phony assumption underlying this debasement of taxonomy to philately holds that the order among organisms stands forth as a simple fact plainly accessible to any half-decent observer. The task of taxonomy may then be equated with the dullest form of cataloging--the allocation of an admittedly large array of objects to their clearly preassigned places: pasting stamps into the designated spaces of nature's album, putting hats on the right hooks of the world's objective hat rack, or shoving bundles into the proper pigeonholes in evolution's storehouse, to cite a standard set of dismissive metaphors.

In maximal contrast, the great Swiss zoologist Louis Agassiz exalted taxonomy as the highest possible calling of all when, in 1859, he opened Harvard's Museum of Comparative Zoology in his adopted land. Each species, Agassiz argued, represents the material incarnation on Earth of a single and discrete idea in the mind of God. The natural order among species--their taxonomy--therefore reflects the structure of divine thought. If we can accurately identify the system of interrelationships among species, Agassiz concluded, we will stand as close as rationality can bring us to the nature of God.

Notwithstanding their maximally disparate judgments of taxonomy, Rutherford and Agassiz rank as strange bedfellows in their shared premise that a single objective order exists "out there" in the "real world" and that a proper classification will allocate each organism to its designated spot in the one true system. (For Rutherford, this order represents a basically boring and easily ascertainable aspect of macroscopic nature--too far removed from the atomic world of fundamental laws and causes to generate much scientific interest or insight. For Agassiz, in greatest conceivable contrast, this order represents our best shot at grasping the otherwise ineffable nature of God himself.)

In framing a modern Goldilockian defense of the importance of taxonomy--far warmer than Rutherford's icy indifference but not quite as hot as Agassiz's impassioned embrace--we must begin by refuting their shared assumption that one true order exists "out there" and that correct classifications may be equated with accurate maps. We can best defend the scientific vitality of taxonomy by asserting the opposite premise: that all systems of classification must express theories about the causes of order and must therefore feature a complex mixture of concepts and percepts--that is, preferences in human thinking combined with observations of nature's often cryptic realities. Good taxonomies may be analogized with useful maps, but they reveal (as do all good maps) both our preferred mental schemes and the pieces of external reality that we have chosen to order and depict in our cartographic effort.

This acknowledgment that taxonomies can express nature's objective realities only in terms of theories devised by the human mind should not encourage any trendy postmodern pessimism about the relativity of knowledge. All taxonomies do not become equally valid simply because each must filter nature's facts through sieves of human thought and perception; some popular attributions of former centuries may be dismissed as just plain wrong (corals, for example, are animals, not plants). Other common schemes may be rejected as more confusing than helpful in nearly all situations (we learn more about whales by classifying them genealogically with mammals than by amalgamating them with squids and sharks into an evolutionarily heterogeneous group of "things that swim fast in the ocean").

Professional taxonomists have always recognized this inequality among systems of naming by proclaiming the search for a natural classification as the goal of their science. Although we may regard the word "natural" as a peculiar, even arrogant, description for an optimal scheme of classification, the rationale for this verbal choice seems clear enough. If all taxonomies must express theories about nature's order, then we may define the most natural classification as the scheme that best respects, reveals, and reflects the causes that generated the diversity of organisms (thereby evoking our urge to classify in the first place!).

A zoo director might, for practical purposes, choose to classify organisms by size (as a convenience for selecting cages) or by climatic preferences (so his polar bears won't asphyxiate in an exhibit on tropical rainforests). But we would label such taxonomic schemes artificial, because we know that evolution has generated the interrelationships among organisms by a process of genealogical descent through geological time. The most natural classification may therefore be defined as the scheme that best permits us to infer the genealogical connections among organisms--that is, the primary cause of their similarities and differences--from the names and forms of our taxonomies.

When we recognize all influential classifications as careful descriptions of organisms made in the light of fruitful theories about the causes of order, we can finally appreciate the fascination of taxonomy as a source of insight about both mind and nature. In particular, the history of changing classifications becomes far more than a dull archive or chronicle of successive purchases from nature's post office (discoveries of new species), followed by careful sorting and proper pasting into preassigned spaces of a permanent album (taxonomic lists of objectively defined groups, with room always available for new occupants in a domicile that can grow larger without changing its definitive style or structure). Rather, major taxonomic revisions often require that old mental designs be razed to their foundations so that new conceptual structures may be raised to accommodate radically different groupings of occupants.

In the obvious example of this essay, Agassiz's lovely cathedral of taxonomic structure, conceived as a material incarnation of God's mentality, did not collapse because new observations disproved his central conviction about the close affinity of jellyfish and starfish (now recognized as members of two genealogically distant phyla, falsely united by Agassiz for their common property of radial symmetry). Instead, the greatest theoretical revolution in the history of biology--Darwin's triumphant case for evolution--revealed a fundamentally different causal basis for taxonomic order. Evolution fired the old firm and hired a new architect to rebuild the structure of classification, all the better to display the "grandeur" that Darwin had located in "this view of life." (Ironically, Agassiz opened his museum in 1859, the same year that Darwin published the Origin of Species. Thus, Agassiz's replica of God's eternal mind at two degrees of separation--from the structure of divine thought to the taxonomic arrangement of organisms to the ordered display of a museum--became an unintended pageant of history's genealogical flow and continuity.)

But the argument that the history of taxonomy wins its fascination, at least in large part, as a dynamic interplay of mind (changing theories about the causes of order) and matter (increased and more accurate understanding of nature's factuality) now exposes a paradox that defines the central theme of this essay and leads us back to the official founder of taxonomy, Carolus Linnaeus. Darwinian evolution has set our modern theoretical context for understanding the causes of organic diversity. But if taxonomies always record theories about the causal order that underlies their construction, and if evolution generated the organic resemblances that our taxonomies attempt to express, then how can Linnaeus, a creationist who lived a full century before Darwin discovered the basis of biological order, be the official father of modern--that is, evolutionary--taxonomy? How, in short, can Linnaeus's system continue to work so well in Darwin's brave new world?

Perhaps we should resolve this paradox by demoting the role of theory in taxonomy. Should we embrace Rutherford's philatelic model after all and regard organic interrelationships as simple, observable facts of nature, quite impervious to changing winds of theoretical fashion? Linnaeus, in this philatelic view, may have won success by the simple virtue of his superior observational skills.

Or perhaps we should argue, in maximal contrast, that Linnaeus just lucked out in one of history's most felicitous castings of dice. Perhaps theories do specify the underlying order of any important taxonomic system, and Linnaeus's creationist account just happened to imply a structure that, by pure good fortune, could be translated without fuss or fracture into the evolutionary terms of Darwin's new biology.

I will advocate a position between these two extremes of exemplary observational skill in an objective world and pure good luck in a world structured by theoretical preferences. Linnaeus was, no doubt, both the premier observer and one of the smartest scientists of his (or any) age. But following my central claim that taxonomies must be judged for their intrinsic mixture of accurate observation and fruitful theory, I will argue that Linnaeus has endured because he combined the best observational skills of his time with a theoretical conception of organic relationships that happens to mirror--but not by pure accident--the topology of evolutionary systems, even though Linnaeus himself interpreted his organizing principle in creationist terms. (As for the fascinating, and largely psychological, question of whether Linnaeus devised a system compatible with evolution because he glimpsed "truth" through a glass darkly or because his biological intuitions subtly and unconsciously tweaked his theoretical leanings in an especially fruitful direction--well, as for all inquiries in this speculative domain of human motivation, I suspect that Linnaeus took this particular issue, with his mortal remains, to the grave.)

We refer to Linnaeus's system as binomial nomenclature because the formal name of each species includes two components: the generic designation, given first with an initial uppercase letter (Homo for us, Canis for dogs, and so on), and the so-called trivial name, presented last and in all lowercase letters (sapiens to designate us within the genus Homo and familiaris to distinguish dogs from other species within the genus Canis--for example, the wolf, Canis lupus). Incidentally, and to correct a common error, the trivial name has no standing by itself and does not define a species. The name of our species, using both parts of the binomial designation, is Homo sapiens, not sapiens. We regard the 1758 version of Systema Naturae as the founding document of modern animal taxonomy because in this edition and for the first time, Linnaeus used the binomial system in complete consistency and without exception. (Previous editions had delineated some species binomially and others by a genus name followed by several descriptive words.)

The binomial system includes several wise and innovative features that have ensured its continuing success. But for the theme of this essay, the logical implications of the system for the nature of interrelationships among organisms stand out as the keystone of Linnaeus's uncanny relevance in Dar win's thoroughly altered evolutionary world. The very structure of a binomial name encodes the essential property that makes Linnaeus's system consistent with life's evolutionary topology.

Linnaeus's taxonomic scheme designates a rigorously nested hierarchy of groups (starting with species as the smallest unit) embedded within successively larger groups (species within genera within families within orders and so forth). Such a nested hierarchy implies a single branching tree with a common trunk that ramifies into ever finer divisions of boughs, limbs, branches, and twigs. This treelike form just happens to express the hypothesis that interrelationships among organisms record a genealogical hierarchy built by evolutionary branching. Linnaeus's system thus embodies the causality of Darwin's world.

This correspondence between the Linnaean hierarchy and life's evolutionary tree achieves its clearest expression in pictorial form. The illustration on page 18 shows a Linnaean ordering of box within box; for alternative expressions of this hierarchy, see the diagrams of sequential genealogical splitting, opposite. Here we have a successive carving of the kingdom of all animals into, first, chordates contrasted with all other animals; then, vertebrates contrasted with all invertebrates; mammals contrasted with all other vertebrates; the order Carnivora contrasted with all other mammals; the family Canidae contrasted with all other carnivores; the genus Canis contrasted with all other canids; and finally, dogs contrasted with all other members of the genus Canis. (I stated that binomial nomenclature expresses the first step of this hierarchical ordering--and thus presents a microcosm of the entire scheme--because the two parts of a species' name record the first act of embedding smaller units within more inclusive groups of relatives. The name Canis familiaris states that this particular smallest unit, the dog species, ranks as one member of the next most inclusive group, the genus Canis, which unites all other species [including the wolf, Canis lupus, and the coyote, Canis latrans] that originated from a common ancestor shared by no other species in any other group.)

Linnaeus thought that his chosen scheme of mapping biological relationships as smaller boxes within successively larger boxes, until all units nested within the most inclusive box of life itself, represented the best human device for expressing the eternal order that God had chosen when he populated the universe. I doubt that Linnaeus ever explicitly said to himself (for I suspect that his mental mansion included no room for such a thought): "But if, quite to the contrary, life evolved by a process of ever expanding branching from a single ancestor over a long period of time, then the hierarchical order of the binomial system will capture the topology of organic relationships just as well, because the logic of my system translates pictorially into a tree with a single trunk at the base, which subsequently divides into branches that never coalesce thereafter. I will therefore hedge and win in either case. For my chosen topology might represent either God's permanent order, preconceived from the first, or the happenstance of historical change and development on an evolutionary tree growing from a single starting point under the constraint of unbroken continuity (although branches may die and fall from the tree as lineages become extinct) and continuous bifurcation without subsequent joining of lineages."

I emphasize this property of irrevocable branching without subsequent amalgamation because the Linnaean logic of placing small boxes into larger boxes--which just happens to conform to the historical reality of Darwin's system--establishes just such a map of organic relationships as its primary and inevitable consequence. One can't, after all, either in Linnaean logic or in the real world, cram big boxes into smaller boxes. Therefore, for example, two species in the same genus can't reside in different families, and two orders in the same class can't be placed in different phyla. If lions and tigers rank as two species in the same genus (Panthera), they cannot then be allocated to different families of higher rank (lions to the Felidae and tigers to the Canidae, for example), for the two larger family boxes would then have to fit within the smaller box of the genus Panthera, and both the rules of Linnaean logic and the requirements of Darwinian evolutionary history would be fractured. I can be a monkey's uncle or a horse's ass only in a metaphorical sense, for my species fits into the small box of the genus Homo, which must nest within the larger box of the family Hominidae, and one member of my species can't opt out of our box to join the Cercopithecidae or the Equidae, thus splitting a coherent lower group into two higher groups. So just watch what you call me, you miserable skunk!

Did Linnaeus therefore just enjoy a little bit of luck in choosing the one logic for a creationist system that would also fit without fuss into a new universe of historical evolution by branching? At least he has demonstrated exemplary survival skills in passing the test of time as taxonomy's father. But I hesitate to ascribe his remarkable success to pure dumb fortune--for a primary reason that calls upon the key contention of this essay: that taxonomies transcend simple description and always embody particular theories about the causes of order, thus melding preferences of mind with perceptions of nature.

I think that Linnaeus succeeded because, however unconsciously or preconsciously, he made some excellent decisions about both the mental and perceptual aspects of taxonomic systems. On the perceptual side, he must have seen better than any of his colleagues that under the logic of hierarchy and branching, organisms could be arranged into a consistent order that might win general assent without provoking constant bickering among practitioners. Other contemporaries had proposed very different logics of classification but had never found a way to push them through to an unambiguous and consistent system. In the most telling example, Linnaeus's most famous contemporary and archrival, France's celebrated naturalist Georges-Louis Leclerc, comte de Buffon (1707-88), had struggled through more than forty volumes of his Histoire naturelle--in my judgment, the greatest encyclopedia of natural science ever written--to develop, without conspicuous success, a nonhierarchical system that joined each species to some others by physiology, to a different group by anatomy, and to a still different set by ecology.

But I would, in addition, like to advance the unfamiliar argument that Linnaeus also succeeded because he made a very clever, and probably conscious, choice from the mental side of taxonomic requirements as well. In deciding to erect a hierarchical order based on continuous branching with no subsequent joining of branches, Linnaeus constructed his system according to the most familiar organizing device of Western logic since Aristotle (and arguably of our innate and universal mental preferences as well): successive (and exceptionless) dichotomous branching as a system for making ever finer distinctions. In a logical tree of this form, often called a dichotomous key, one may move in either direction: down the tree, to place a particular basic object into ever larger groups by joining successive pairs, or up the tree, to separate a large category into its component parts by successive twofold division.

One may, for example, interpret the branching diagram presented earlier (see page 24) as a dichotomous key. We can reach dogs by starting with the largest category of all animals, making a twofold division into vertebrates and invertebrates, then splitting the vertebrates into mammals and nonmammals, the mammals into carnivores and noncarnivores, the carnivores into canids and noncanids, and finally, the canids into dogs and other canines. (We can also work outward in the opposite direction--by successive joining of pairs--to learn how dogs fit into the hierarchy of all animals.)

In fact, the idea for this essay came to me when I recently purchased an obscure late-sixteenth-century book on Aristotelian logic and noted that its numerous charts for working through the categories of reasoning and the attributes of human form and behavior had all been constructed as dichotomous maps bearing an uncanny resemblance to the taxonomic keying devices that I have seen and used in texts and guidebooks for naturalists throughout my career. Thus, Linnaeus gave himself quite a leg up by building his taxonomic system upon a familiar form of logic that scholars had applied to all subjects, scientific and otherwise, from the dawn of Western history--a style of reasoning, moreover, that may track the basic operation of our brains.

I took the chart reproduced above from this 1586 treatise, published in Paris by the physician Nicolas Abraham and entitled Isogogethica ad rationis normare delineata (An introduction to ethics as delineated by the rule of reason). Abraham first divides the domain of ethical decisions into the dichotomous pair of mentis (by the mind) and moris (by custom). He then splits the lower domain of custom into the two categories of privatis above and publicis below. (Interestingly, and I suspect consciously, authors of dichotomous keys also seem--at least in my limited observation of such devices from pre-Darwinian times--to order their pairings from the good and most valued on top to the least admirable on the bottom. In this case, reason beats custom, while within custom, private decisions--presumably motivated by personal belief-trump public actions, which may be enforced by social pressure. I am particularly fond of the dichotomous key for birds of prey that the great English naturalist John Ray published in 1678, with a first division of day fliers on top and night fliers on the bottom; a second division of the preferred day fliers into bigger species above and smaller below; and a third division of the big species into "more generous" eagles above and "more cowardly and sluggish" vultures below.)

But let us follow Abraham's key for the higher category of mental decisions (mentis), which then undergoes a further dichotomous split into sapientia (done by wisdom) above and prudentia (done for reasons of prudence) below. The third and final set of twofold divisions then separates judgments by sapientia into intelligentia (achieved by pure reason) above and scientia (achieved by knowledge about material things) below. The lower judgments of prudentia then divide into a preferred category of bona consultatio (derived by seeking good advice from others) above and the less worthy dichotomous alternative sagacitas (determined by our own judgment) below.

I do admire Linnaeus as an intellectually driven and brilliantly complicated, but arrogantly vainglorious, man. If I preferred the hagiographical mode of writing essays, I would stop here with a closing word of praise for Linnaeus's perspicacity in harnessing both the observational and theoretical sides of his mental skill to construct a flexible and enduring taxonomic system that could survive intact under the greatest theoretical transformation in the history of biology.

But he who lives by the sword dies by the sword (as Jesus did not exactly say in a common misquotation that remains potent in truth and meaning despite its inaccuracy in citation). Linnaeus's consistency and wisdom in developing and defending the binomial system of hierarchical classification carried him through to intellectual victory. But like so many originators of grand and innovative systems, he reached too far (whether by overconfidence or over-excitement) and became too committed to his procedure as the one true way for classifying any collection of related objects. (I cannot help recalling my experience with a customs official on a small West Indian island, who recorded my land snails as turtles because his forms permitted only a distinction between warm-blooded and cold-blooded animals and the word "animal," in his personal understanding, designated only vertebrates. Thus, snails became turtles because both are cold-blooded and move with legendary torpor.)

Once Linnaeus had fully developed the binomial system and its supporting logic of a consistently nested hierarchy, he supposed that he had discovered the proper way to classify any group of natural objects, and he therefore began to give binomial species names to several classes of inappropriate phenomena, including rocks and even human diseases. Clearly, he had become over-enamored with his own device and had lost sight of the key principle that hierarchical embedding by dichotomous branching captures the causal order only within certain kinds of systems, particularly those that develop historically by successive branching in unbroken genealogical continuity (with no later amalgamation of branches) from a common ancestor. The fact that Linnaeus tried to apply the binomial system to several groups of objects that, by their own rules of order or development, patently violate the required hierarchical logic indicates that perhaps he never did really grasp the limitations (and therefore the essence) of his system. So perhaps Linnaeus did prevail partly by the luck of organic conformity to his logic rather than by his correct and conscious reasoning about the causes of relationships among plants and animals.

For example, a page from the seventh (1748) edition of Systema Naturae (see page 74) designates binomial species of the genus Quartzum from the classification of rocks and minerals that Linnaeus presented as a third chapter, following his taxonomies for animals and plants. The first "species," Quartzum aqueum (transparent quartz), includes ordinary glasslike quartz; the second, Quartzum album (white quartz), encompasses less valued, opaquely waterworn quartz pebbles; the third, Quartzum tincture (colored quartz), gathers together the tinted varieties that mimic more valuable gemstones (Linnaeus calls them false topaz, ruby, and sapphire, for example); and the fourth, Quartzum opacum (opaque quartz), describes the even less useful and less transparent flintstones.

But the nature of quartz, and the basis of relationships among minerals in general, defies the required logic of causality for any system legitimately described in Linnaean binomial terms. The members of Quartzum aqueum, for example, do not hang together as a set of closest historical relatives, all physically derived in continuity from a common ancestor that generated no other offspring. Rather, the specimens of this false species look alike because simple rules of chemistry and physics dictate that transparent quartz will form whenever silicon and oxygen ions come together under certain conditions of temperature, pressure, and composition. The members of this "species" maintain no historical or genealogical coherence. One specimen might have originated half a billion years ago from a cooling magma in Africa, and another just fifty years ago in a bomb crater in Nevada. Minerals must be classified according to their own causes of order--a set of rules distinctly different from the evolutionary and genealogical principles that build the interrelationships among organisms.

Linnaeus clearly overreached in supposing that he had discovered the one true system for all natural objects. In the twelfth and final edition of Systema Naturae (1766), he included a section entitled Imperium Naturae, dedicated to extolling his hierarchical and binomial method as universally valid. God made all things, Linnaeus argues, and must have used a single and universal method, now discovered by his most obedient (and successful) servant. Linnaeus writes: "Omnes res creatae sunt divinae sapientiae et potentiae testes" ("All created things are the witnesses of divine knowledge and power"). Using a common classical metaphor (the thread of Ariadne that led Theseus out of the labyrinth after he had killed the Minotaur), Linnaeus praises himself as the code cracker of this universal order: "Knowledge of nature begins with our understanding of her methods by means of a systematic nomenclature that works like Ariadne's thread, permitting us to follow nature's meanders with accuracy and confidence."

Ironically, however, Linnaeus had succeeded (in a truly ample, albeit not universal, domain of nature) precisely because he had constructed a logic that correctly followed the causes of order in the organic world but that could not (for the same reasons) be extended to cover inorganic objects not built and interrelated by ties of genealogical continuity and evolutionary transformation. The strength of any great system shines most brightly in the light of limits that give sharp and clear definition to the large, but not infinite, domain of its legitimate action. By understanding why Linnaean logic works for organisms and not for rocks, we gain our best insight into the importance of his achievement in devising a system that he applied too widely but that later allowed us to specify the varied nature of disparate causes for nature's order among her many realms.

On the same theme of power in exceptions, and to make a somewhat ironic point in closing, Linnaeus's hope that he had discovered a fully universal basis (God's own rules of creation) for classifying all natural objects has recently suffered another fascinating blow. Science had already denied Linnaeus's universality more than 200 years ago by validating his procedures only for historically generated genealogical systems (the evolution of organisms) and by rejecting his binomial schemes for rocks or diseases with other theoretical foundations of order. But now one of the most important biological discoveries of our age has also challenged the universal application of Linnaean taxonomy--but this time from the inside (that is, from the world of organisms).

We need not fret for fat, furry, multicellular creatures--the plants, fungi, and animals of our three great macroscopic kingdoms of life. For evolution, in this visible world of complex creatures, does follow the Linnaean topology effectively all the time. That is, the basic structural rule that validates the binomial system works quite satisfactorily at this level, for branches never join once they have separated, and each species therefore becomes a permanently independent lineage, making no further combinations with others after its origin. Evolution cannot make a nifty new species of mammal by mixing half a dolphin with half a bat to generate an all-purpose flier and swimmer.

Until a few years ago, we thought that this rule of permanent separation also applied in the simplest world, unicellular bacteria--the true dominators of Earth and rulers of life, in my opinion (see my 1996 book Full House). In other words, we assumed that the bacterial foundation of the tree of life grew in a fully Linnaean manner, just like the multicellular section. (Actually, and to emphasize the importance of the discovery described below, the bacterial domain occupies most of life's tree, because the three multicellular kingdoms sprout as three terminal twigs on just one of the tree's three great limbs, the other two being entirely bacterial.)

Apparently we were wrong. By a set of processes collectively called lateral gene transfer (LGT for short), individual genes and short sequences of genes can move from one bacterial species to another. For two reasons, these transfers may challenge Linnaean logic in a serious way. First, LGT does not seem to respect taxonomic separation. That is, genes from genealogically distant bacterial species seem just as likely to enter a host species as do genes from closely related species. Second, the process is apparently not rare enough to permit dismissal as a peculiar exception to the prevailing Linnaean rule of strict branching with no subsequent amalgamation. (If only a percent or two of bacterial genomes originated by import from distant species via LGT, we could view the phenomenon as a fascinating anomaly that does not degrade the primary signal of Linnaean reality. But at least for some species, LGT may be sufficiently common to shine as a primary signal of its own. In the familiar E. coli, for example, 755 of 4,288 genetic units--about 18 percent of the entire genome--have been introduced in at least 234 events of lateral genetic transfer during the last 100 million years.)

Professional evolutionary biologists have been puzzled and excited by these discoveries about LGT. But the word has hardly filtered through to the interested public--an odd situation, given the status of LGT as a challenge to one of our most basic assumptions about the nature and fundamental topology of evolution itself, not to mention the foundation of Linnaean logic as well! Perhaps most of us just don't care much about invisible bacteria, whereas we would sit up and take notice if we heard that LGT played a major role in the evolution of animals. Or perhaps the issue strikes most people as too abstract to command the same level of attention that we heap and hype upon such events of minimal theoretical interest as the discovery of a new carnivorous dinosaur larger than Tyrannosaurus. But I would not so disrespect the concerns of public understanding. Properly explained, the theoretical challenge of LGT to some truly fundamental views about the nature of evolution and classification should be fascinating to all people interested in science and natural history.

To put the matter baldly, if LGT plays a large enough role in bacterial evolution to overcome the Linnaean signal of conventional branching without subsequent joining, then binomial logic really doesn't work. An honest diagnosis could not then recommend that we make some minor repairs or apply some small plaster patches, for the Linnaean system would be truly broken by the collapse of its central theoretical prerequisite. The hierarchical basis of Linnaean logic demands that life's history be built as a tree, without amalgamation of branches once a lineage establishes its independence. But if LGT dominates the composition of bacterial genomes, then trees cannot express the topology of evolutionary relationships, because the pathways of life would then form a meshwork--as bacteria evolve by importing genes from any location on the genealogical net, no matter how evolutionarily distant.

But don't trust this expert on land snails (in the realm of fat furry things) and diligent essayist on subjects beyond his genuine expertise. Just consider these measured words from a technical article by my close colleague, the leading researcher on the subject, W. Ford Doolittle, of Dalhousie University in Halifax. In the June 25, 1999, issue of Science (a special report on evolution from America's leading journal for professional scientists), Doolittle wrote, in an article entitled "Phylogenetic Classification and the Universal Tree":

If "lateral gene transfer" can't be dismissed as trivial in extent or limited to special categories of genes, then no hierarchical universal classification can be taken as natural. Molecular phylogeneticists will have failed to find the "tree tree," not because their methods are inadequate or because they have chosen the wrong genes, but because the history of life cannot properly be represented as a tree.

Do not lament for the spirit of Linnaeus. Yes, his dreams about the discovery of a universal system suffered two sequential blows: first, soon after his death, when scientists recognized that his logic worked only for organisms and not for rocks and the rest of the natural world; and second, as discovered only in the last decade, when Linnaean taxonomy encountered a strong biological challenge from the frequency of lateral gene transfer--the ultimate tree buster--in the substantial domain of bacteria, albeit not in our own world of multicellular life.

As a truly great scientist, Linnaeaus understood the central principle that honorable error (through over-extension of exciting ideas) comes with the territory, and that theories gain both strength and better definition from principled limitations upon their realm of legitimate operation. Moreover, as the modern founder of the truly noble science of taxonomy, Linnaeus also understood that all classifications must embody passionate human choices about the causes of order--in short, theories that must be subject to continuous revision and correction--and cannot record the accretion of pure and unchanging descriptions of objective nature on the philatelic model.

Thus, taxonomies must express both concepts and percepts--and must therefore teach us as much about ourselves and our mental modes as about the structure of external nature. Surely Linnaeaus, of all people, comprehended this fundamental and ineluctable interrelationship of mind and nature, for when he composed, at the very beginning of Systema Naturae, his formal description of his newly crowned species, Homo sapiens, he linked us (in various editions)--in only one case correctly, as we now know-with three other mammals: monkeys, sloths, and bats. For each of these three, Linnaeus penned a conventional and objective description in terms of hairiness, body size, and the number of fingers and toes. But for Homo sapiens, he chose the path of terseness and wrote just the three Latin words of another familiar motto. Not Natura non facit saltum this time, but the foremost intellectual challenge of classical wisdom: Nosce te ipsum--Know thyself.(*)

(*) I would like to dedicate this essay to Ernst Mayr, the greatest taxonomist of the twentieth (and twenty-first) century, who remains as intellectually active as ever at age ninety-six, and who taught me, through his writing and the human contact of personal friendship, the central principle of our science (and of this essay): that taxonomies are active theories about the causes of natural order, not externally provided stamp albums for housing nature's obvious facts.

: Linnaeus's classification scheme can be visualized as a series of nested boxes in which the species is the irreducible category.

: Alternative ways of visualizing Linnaeus's scheme include a progressively inclusive hierarchy, top, and a branching diagram, bottom.

French physician Nicolas Abraham published this chart for classifying types of ethical decisions in his treatise of 1586.

On this page of Linnaeus's Systema Naturae (1748 edition), the author extends his binomial taxonomy of animals and plants to cover rocks and minerals.

10. WE ARE ALL MONKEYS' UNCLES 

Section:

This View of Life

If kings are to hermits as we are to chimps and gorillas, was Darwin wrong?

We learn from our errors, perhaps most of all from our shameful mistakes. I therefore begin with a story at my own expense. Many years ago, one of my students told me about her father's brother, a severely retarded man of childlike disposition. When she described him as "my uncle," I did a mental double take (and fortunately said nothing, so the shame of my error remained internal until now). I said to myself: "Uncles are wise people who render free advice (not always worthwhile) and take you to baseball games; how can a person with such limits be an uncle?" I then kicked myself (also metaphorically) and continued the soliloquy: "He is her father's brother; he is therefore her uncle pure and simple; uncle is a genealogical term of relationship, not a functional concept of action; he is as good and as true an uncle as any man who ever lived."

Evolutionary relationships are also genealogical, not primarily functional. We all understand that whales are mammals by history of common descent, not fishes because they swim in the ocean. In genealogical terms, closeness is defined by position in a sequence of branchings-what Darwin called propinquity, or relative nearness. I may look and act more like my cousin Bob than my brother Bill, but Bill is still closer to me by genealogy. Function and appearance need not correlate strongly with genealogical propinquity. To cite a classic example used before in these columns: all evolutionists agree that genealogical relationships among trout, lungfishes, and cows are correctly described in the accompanying diagram. Terrestrial vertebrates branched off the line of early fishes at a point near the ancestors of modern lungfishes; trout evolved much later from a persisting earlier line of fishes. Therefore, if we choose to classify purely by genealogy, lungfishes and cows must be placed together in a group separate from trout. Many of us rebel against such an idea because our conventional classifications mix functional and strictly genealogical relationships. We may say that a lungfish looks like a fish, swims like a fish, acts like a fish and (presumably, for I have never had the pleasure) tastes like a fish. Therefore, it is a fish. Well, perhaps so; but by propinquity, lungfishes are closer to cows.

I don't wish to pursue this theoretical point in classification any further in this essay-although aficionados should note that this is the issue now engulfing the science of systematics in the debate about "cladism." Cladists advocate classification by pure genealogy (branching order), with no attention whatsoever to traditional concepts of similarity in function or biological role. For this essay, we need only carry away the lesson that genealogical and functional similarities are different concepts, and that we can be terribly fooled when we make a mistaken equation-particularly when we assume a closeness in branching (propinquity) from evidence of common appearance or behavior.

(Sorry, but I must add one more didactic paragraph: if we call a whale a fish, we make a simple error by misunderstanding the evolutionary phenomenon of "convergence." The fishlike characters of whales evolved separately and independently in a line derived from fully terrestrial vertebrates. But the fishy similarities of trout and lungfishes are genuine evolutionary marks of common ancestry. These similarities don't forge a closer genealogical bond between lungfish and trout than between lungfish and cow because such shared features are common characters of all early vertebrates; propinquity is marked by shared characters of later derivation. I would not, for example, use the character "five fingers" to unite humans and dogs, while placing seals in another group-for dogs and seals are genealogically close as members of the order Carnivora. Five fingers is a shared character of all ancestral mammals; it cannot help us make divisions within later mammalian evolution.)

If you have found the foregoing lesson abstract and dull, let me now reward your patience with a wonderful story (that becomes even better when you absorb the lesson). In functional terms, we would acknowledge maximal disparity between a king in his castle and a hermit in a hovel. But, as I argued above, functional and genealogical similarities need not be strongly correlated. Our legends are replete with scenarios of rags to riches: paupers become kings and frogs turn into princes. All the world's opulence does not debar the possibility that a king's closest cousin might be the meanest hermit in the land.

Let us now contrast the kings and hermits, explicitly so called, of the world of crabs. We could scarcely find two more apparently different creatures in this admittedly limited domain. The king crab (Paralithodes camtschatica), a paragon of size within the brotherhood, lives in arctic and north temperate waters from the northern tip of Vancouver Island, all around Alaska, over to Siberia, and down the eastern Pacific margin as far as Japan. To borrow my earlier formulation for lungfishes, it looks like a crab, moves like a crab, acts like a crab, and certainly tastes like a crab-the basis for a prosperous Alaskan "fishery" (the correct English word, if taxonomically inaccurate in this case), which, at its height in the early 1960s, yielded 180 million pounds per year and a revenue equal to 40 percent of what the lucrative salmon trade provided. (Severe recent declines may be due to parasitism, disease, or overfishing-there we go again, with our chauvinistic vertebrate-centered etymologies.) The largest individual ever captured had a leg spread of just under five feet and weighed 24.5 pounds. Ten pounders with a three-foot leg span are common in the trade.

By contrast, consider the humble hermit crab-actually a large group of related forms, including some 800 species in more than 80 genera. Most are an inch or two in length and live curled up inside an empty snail shell (which they eventually outgrow and "trade in" for a larger model). However great the difference in size and habits, the disparity in form between king crabs and typical hermit crabs is even more pronounced. King crabs look like ordinary crabs: their carapace (outer shell) is flattened and widened, and they bear a pair of claws up front and three pairs of long sturdy legs behind (most crabs have four pairs behind the claws).

By contrast, I don't know why anyone ever decided to designate the hermits as crabs in the first place. Crabs form one of three major divisions-with lobsters and shrimps as the others-within the large group of marine crustaceans called Decapoda. (The Arthropoda, biggest of all phyla, contains three great groups: the Crustacea; the Uniramia, including insects, millipedes, and centipedes; and the Chelicerata, including spiders, scorpions, and horseshoe crabs.) True crabs belong to the order Brachyura, meaning "short tail." As a defining feature, their abdomens (rear ends) are shortened and narrowed, tucked around the back of the body, and firmly pressed against the underside. (The flat and wide crab shell corresponds with the front part only of a lobster or a shrimp's body. The abdomen, source of good eating, extends out and back in shrimps and lobsters but disappears from sight-as a remnant tucked underneath the body-in crabs. Take the front end of a lobster, flatten it out, pull from both sides until the shell becomes wider than long, reduce the tail and tuck it under the body-and, voila, you have a crab. The relationship among the three major decapod groups becomes clearer with this thought experiment.)

So why call hermits crabs at all? They are not members of the Brachyura by genealogy but form a separate group, called Anomura, in a never-never land between conventional shrimps and other decapods. Their bodies are elongate, as in shrimps. They have only two strong pairs of legs behind the frontal pair of claws (the two highly reduced pairs farther behind function to hold the animal within its borrowed shell). Most importantly, the abdomen is not reduced or folded up under the body. Instead, it is strongly altered and well adapted for fitting into snail shells. Hermit crab abdomens are soft and decalcified, all the better to slip neatly into a shell. Moreover, the abdomen is coiled to one side, mimicking the shell that will serve as its abode. So why are these creatures called hermit crabs? I would have thought that hermit shrimps fit appearances better.

And yet, experts have suspected for a long time that king crabs are not true brachyurans either, and that these Alaskan giants (and other members of their family Lithodidae) are closest cousins of hermit crabs. But how could such propinquity in genealogy permit the development of such maximal disparity in form and function? And how, given this disparity, did anyone ever suspect propinquity in the first place? Three arguments have been presented, and they make a strong, if not entirely convincing, case.

1. The abdomen of adult king crabs, although diminished in size and folded under the body as in true crabs, is asymmetrical in form, recalling the rear end of hermit crabs. A few other features of adult anatomy also suggest hermit crab origins. Decapoda, the crustacean group of crabs, lobsters, and shrimps, means ten-legged. In true crabs, a frontal pair of claws and four posterior pairs of legs make up the complement of ten. In hermit crabs, as stated above, only two pairs of strong legs follow the claws, with the final two pairs reduced to small protuberances that grasp the borrowed snail shell. In king crabs, the first pair of reduced legs is secondarily enlarged to form a third pair of strong legs behind the claws; but the second pair remains small and inconspicuously situated under the body.

2. These sporadic similarities in adult form would never have made a strong case by themselves. Confidence in this odd linkage of kings and hermits rose, however, with the discovery of profound and pervasive likenesses in the larval forms of the two groups. Adult animals are often so strongly specialized and differentiated that most signs of ancestry are hidden or obliterated. But early larvae or embryos often retain the ancestral mode of development, in part because the complex assembly of adult from egg leaves little flexibility for substantial modification and in part because larval environments often remain stable while adult habitats change. I like to call this common (but by no means invariable) observation of larval conservatism the Sacculina principle, to honor a famous parasite of crabs (as it happens) that looks like little more than a blob of formless reproductive tissue when adult in the host's body, but shows clear signs of its barnacle ancestry in free-living larval stages.

On the Confucian theme of equating a good picture with 10,000 words, the accompanying figure, from a crucial 1957 article that established the point, shows glaucothoe (late larval) stages of Pagurus bernhardus, a standard hermit crab, and Lithodes maia, a smaller relative of king crabs (see J. D. MacDonald, R. B. Pike, and D. I. Williamson, Proceedings of the Zoological Society of London, vol. 128, pp. 209-57). Some of the adult differences are already established (although the abdomens have yet to assume their asymmetry): the king crab cousin has already developed its characteristic spines and elongated the third pair of legs behind the claws. But the striking similarities of form now overwhelm the differences.

3. In the most fascinating and general point of all, convergent evolution to crablike form is an oft-repeated trend in decapod crustaceans. I will not speculate on either the advantages or ease of such a transformation, but merely record its multiple occurrences. Flatten the carapace, pull it out to the sides, suppress the abdomen and curl it under the body-and you have a crablike creature. So common is this trend that it even has a special name-carcinization ("crabification" in the less dignified vernacular)--conferred in 1916 by the celebrated British zoologist L. A. Borradaile. (Remember that we also call a cancer-producing substance a carcinogen, and that cancer itself comes from the Latin word for crab-a reference to the central mass and clawlike extensions of many tumors.)

Many evolutionary lines of hermit crabs have undergone carcinization. In some, the result is only partial-but halfway points give us especially valuable insights into the full process. Consider the accompanying picture of Probeebei mirabilis, a partly carcinized hermit crab properly classified in 1961 by the Danish zoologist Torben Wolff ("Description of a Remarkable Deep-sea Hermit Crab, with Notes on the Evolution of the Paguridea," Galathea Report, vol. 4, pp. 11-32). Note that the abdomen is still asymmetrical and twisted to the right, but it has become secondarily calcified. The two pairs of legs behind the claws are now strongly developed for free walking and extended to the sides, rather than protruding from the front (the proper position for sticking out from a snail shell). The basic reasons for such a change are probably not too far to seek in this case. Probeebei lives in deep waters off the coast of Costa Rica (Wolff's specimens came from a depth of more than 10,000 feet). Snail shells (and other potential homes) are rarely available at such depths.

Two other cases hold special interest for understanding the transition and its frequent occurrence. Porcellanopagurus, the subject of Borradaile's original study, develops a shortened and fairly symmetrical abdomen. But this creature uses a clam shell, rather than a snail shell, for a cover-and you don't have to twist to fit under a basically flat plate. Birgus latro, the large and well-known "robber" or "coconut" crab of Pacific islands, shows us much of the process in its own growth. The adult is fully terrestrial and crablike in appearance, but juveniles still have twisted abdomens and inhabit snail shells at the shoreline.

We may move from these partly carcinized lines to four cases of virtually complete assumption of crablike form. Most successful, of course, are the true crabs (brachyurans) themselves, with thousands of species and worldwide distribution. But three other lines of fully carcinized crustaceans arose from hermit crab ancestry-two groups little known to nonspecialists (the families Lomisidae and Porcellanidae, the porcelain crabs), and the family Lithodidae, including the king crab (and fifty-two other species in sixteen genera-mostly much smaller animals and denizens of cold waters).

If doubts of the close propinquity between hermit crabs and king crabs persisted, they were recently dispelled, and convincing new proof provided, in an elegant study just published in the February 6, 1992, issue of Nature, the inspiration for this essay ("Evolution of King Crabs from Hermit Crab Ancestors," by C.W. Cunningham, N.W. Blackstone, and L. W Buss).

This study, done in the laboratory of my friend and colleague Leo Buss of Yale University, takes advantage of the revolution in taxonomy now under way thanks to recent technological advances that allow us to sequence DNA cheaply and rapidly. Conventional taxonomy struggles with fewer morphological, physiological, and behavioral traits often frustratingly subject to convergence. Sequencing of DNA and RNA provides hundreds or thousands of newly available characters (the ordering of strings of nucleotides, often highly conserved in evolution). These are, of course, equally subject to convergence and other forms of confabulation, but what a bounty of novel evidence!

Buss and colleagues sequenced part of an important gene that codes for ribosomal RNA, and they found 108 "phylogenetically informative" positions-an enormous increase in the number of useful characters for classification. They developed a matrix of similarities for all pairs of comparisons among twelve species of hermit and king crabs and a thirteenth more distant relative, chosen to anchor the tree (and called an outgroup in our jargon; they used the brine shrimp Artemia salina). They then applied a variety of standard tree-building techniques to this matrix of relative similarities. They achieved the same basic result with either of the two most common methods for tree building--distance analysis, which works only with measured degrees of overall similarity; and parsimony, which constructs trees with the minimal number of evolutionary steps. The invariant result from different procedures greatly increases our confidence in their findings.

Their remarkable and enormously satisfying result is shown in the accompanying diagram, reproduced directly from their article. Artemia is, as expected, separated from the twelve other species at the oldest division. The next dichotomy (A on their diagram) follows traditional classification by dividing hermit crabs with large left claws (the two lower species) from their cousins with large right claws. The large upper clump of ten species represents ordinary, traditional hermit crabs of the family Paguridae. The next division (B on their diagram) makes a basically geographic separation within the Paguridae.

We now come to the truly remarkable point: Notice the two lower species in the upper clump-the king crab (Paralithodes camtschatica) and its close relative Lithodes aequispina. Now consider the species in the two major subclumps of this larger group formed at the separation of right- and left-clawed lines at division A. The upper subclump represents species of the genus Pagurus, the standard hermit crab of any textbook or local seashore. But now look at the lower subclump-and note that it includes two further species of the genus Pagurus, along with the two species from the king crab line. In other words, king crabs are so close to hermit crabs by the proper criterion of propinquity that they actually branch off from within a narrowly restricted genealogical grouping so conventional in form and behavior that they have all been included in the canonical genus Pagurus.

The form of the tree also allows us to make a reasonable inference for the time when the king crab lineage split from conventional hermit crabs. Point A, the splitting of left- and right-clawed hermit crabs, can be estimated at some 73 to 78 million years from independent evidence of fossils. The geographic division of regions within right-clawed hermit crabs (point B) occurred some 35 to 40 million years ago, again by independent geological and paleontological evidence. By extrapolation downward, king crabs split from the genus Pagurus some 13 to 25 million years ago-a good stretch of time, but not a great deal (geologically speaking) for the evolutionary work accomplished.

One tangential point before leaving this elegant study. Critics of evolution often charge that the subject is untestable and therefore not properly scientific at all. This claim is rhetorical nonsense. How could you ask for a better test, based on a very risky prediction, than this. The counterintuitive link between king and hermit crabs was postulated on the basis of classical evidence from morphology (the arguments detailed in points 1 to 3 in this essay). This prediction was then tested by the entirely separate data set of DNA sequence comparisons and confirmed in spades, with even closer propinquity than suspected between king crab and hermit crab lines.

I regard this story of king and hermit crabs as one of the most elegant that I have learned of late in evolutionary biology-a lovely combination of a fascinating and counterintuitive tale; a multifaceted, rigorous, and convincing pile of supporting data; and a lesson of intriguing generality (the difference between genealogical propinquity and any functional meaning of similarity-and the overriding importance of propinquity). But can I bring you along with me in the face of an obvious demurral that many readers will offer: yes, I do grasp your story, but I'm not moved very much by crabs. They just don't intersect my life very often, so why should I care? Let me try to overcome this reticence by giving another example of precisely the same evolutionary phenomenon-one to which you simply cannot be indifferent.

The accompanying genealogical diagram epitomizes our surprising crab story. King crabs branch off from the hermit line within the space of the genus Pagurus, the most ordinary and conventional of all hermit crabs. Who would have thought that such a difference could be achieved in so little genealogical space? Who would have imagined that kings and hermits could be so close by the most important of all evolutionary criteria-propinquity, or genealogical distance?

I now reproduce the exact same diagram. I have made no changes whatever in the positions and orderings of branches. I have, however, substituted different names, for I now wish to diagram our best knowledge of propinquity in the so-called higher primates. Interestingly enough-for this was my second inspiration in deciding to write the essay-the genealogical story of how humans fit with closest primate relatives is exactly and formally the same as the tale of propinquity between king crabs and hermit crabs.

Darwin correctly surmised, and little doubt has been entertained by scientists ever since, that chimps and gorillas are our closest relatives. But Darwin, and nearly everyone else until recently, assumed that chimps and gorillas represented the closest genealogical pair among the three species-- only reasonable after all, given the evident similarity between the two apes, and our obviously exalted separateness. (But remember that functional and genealogical similarity need not correspond.) All the evidence is not yet in, and the issue is still subject to wide debate, but most of the latest information suggests that we have been wrong-and that chimps and humans form the closest genealogical pair, with gorillas branching off a bit earlier.

Chimps and gorillas are conventionally classified in the family Pongidae, with humans in the separate family Hominidae. But if my diagram is correct, then humans arise within the space of the Pongidae and cannot therefore represent a separate family, lest we commit the genealogical absurdity of uniting two more distant forms (chimps and gorillas) in the same family and excluding a third creature (humans) more closely related to one of the two united forms. I surely cannot claim to be more closely related to my uncle than to my brother, but we make exactly such a statement when we argue that chimps are closer to gorillas than to humans-see the third diagram of identical topology.

Hermit crabs and king crabs tell exactly the same story. Our instincts inform us that the two groups should be separated in classification to recognize their profound differences in form and function. But king crabs arise genealogically within the space of hermit crabs-indeed within the restricted space of the canonical genus Pagurus. So how can we place king crabs in one evolutionary group and hermit crabs in another? Similarly, how can we continue to rank humans in glorious separateness, while we unite chimps and gorillas in the family Pongidae?

We may legitimately inquire how such apparent differences could arise in such a restricted genealogical space. But perhaps we are fooled by appearances, and the underlying differences are not so great (or perhaps they are truly profound and evolutionary rates have been enormously accelerated in the king crab and human lines). Small underlying changes can yield large accumulated effects if introduced early in growth, with cascading consequences thereafter. Maybe carcinization is not so big a change after all-flatten and widen the carapace and reduce the abdomen. Maybe all this can occur as consequences of a single coordinated transformation in growth (as the authors of the Nature article suggest). After all, Birgus latro, as discussed previously, undergoes such a transformation in its own growth-as it lives with a twisted abdomen in a snail shell during its youth, but then carcinizes and becomes free living as an adult. Moreover, the large size of king crabs, however impressive, need not represent a major evolutionary change. Abandon the necessity of finding a shell for a house, and limits to size are abrogated. Any carcinized free-living hermit crab may possess the capacity for greatly expanded size.

Similarly for humans: are we really so different from chimps as we so confidently and arrogantly assert? In appearance, sure (reduced hair and erect posture have a strong visual impact). In brainpower, undoubtedly (chimps are smart as bell, but they will never ponder the genealogical position of king crabs). But the underlying biological differences need not be so great. Strengthen and straighten the legs, enlarge the brain. The consequences have been enormous and unprecedented in all the history of life, but I am not so sure that the topological and genetic transformations have been so profound. Consequences are effects, and effects are not the same thing as generating forces and morphological results. Small changes can have cataclysmic effects.

People of good will and intelligence readily acknowledge our kinship with apes and monkeys. We know it in our heads and can parrot the appropriate phrases. But we have never incorporated this vital knowledge deep within our guts. We have not been able to do so, in large part, because we have mistakenly assumed that functional and genealogical distances must be strongly correlated. If we look so unlike a chimpanzee, then we must really be very different, whatever our kinship. But if we ever properly grasp the primacy of genealogical distance as an evolutionary measure, and if we ever understand how illusory an outward appearance can be as an indicator of fundamental difference, then we might reassess to our enormous (if humbling) advantage. Kings can be hermits and humans can be closest brethren to chimps.

The motto of the functional view proclaims: Der Mann ist was er isst (you are what you eat). But an evolutionist must add the defining voice of history: you are what you have been and what your closest genealogical nexus shares. Think kinship. We will be a bit freer, a bit more enlightened, a bit readier to work for planetary preservation with the rest of kindred life, when we truly know why each and every last one of us is a monkey's uncle.

11. One article: Carl Linnaeus

The recent discovery of abundant water on Mars, albeit in the form of permafrost, has raised hopes for finding traces of life there. The Red Planet has long been a favorite location for those speculating about extraterrestrial life, especially since the 1890s, when H. G, Wells wrote The War of the Worlds and the American astronomer Percival Lowell claimed that he could see artificial canals etched into the planet's parched surface. Today, of course, scientists expect to find no more than simple bacteria dwelling deep underground, if even that. Still, the discovery of just a single bacterium somewhere beyond Earth would force us to revise our understanding of who we are and where we fit into the cosmic scheme of things, throwing us into a deep spiritual identity crisis that would be every bit as dramatic as the one Copernicus brought about in the early 1500s, when he asserted that Earth was not at the center of the universe.

Whether or not we are alone is one of the great existential questions that confront us today. Probably because of the high emotional stakes, the search for life beyond Earth is deeply fascinating to the public. Opinion polls and Web-site hits indicate strong support for and interest in space missions that are linked even obliquely to this search. Perceiving the public's interest, NASA has reconfigured its research strategy and founded the NASA Astrobiology Institute, dedicated to the study of life in the cosmos. At the top of the agenda, naturally, is the race to find life elsewhere in the solar system.

Researchers have long focused on Mars in their search for extraterrestrial life because of its relative proximity. But twenty-five years ago, as a result of the 1976 Viking mission, many of them became discouraged. A pair of spacecraft had passed through the planet's extremely thin atmosphere, touched down on the surface, and found it to be a freezedried desert drenched with deadly ultraviolet rays. The spacecraft, equipped with robotic arms, scooped up Martian dirt so that it could be examined for signs of biological activity. The results of the analysis were inconclusive but generally negative, and hopes faded for finding even simple microbes on the surface of Mars.

The outlook today is more optimistic. Several probes are scheduled to visit Mars in the coming months, and all will be searching for signs of life. This renewed interest is due in part to the discovery of organisms living in some remarkably hostile environments on Earth (which opens up the possibility of life on Mars in places the Viking probes didn't examine), and in part to better information about the planet's ancient history. Scientists now believe that Mars once had a much thicker atmosphere, higher temperatures, rivers, floods, and extensive volcanic activity — all conditions considered favorable to the emergence of life.

The prospects for finding living organisms on Mars remain slim, of course, but even traces of past life would represent a discovery of unprecedented scientific value. Before any sweeping philosophical or theological conclusions could be drawn, however, it would be necessary to determine whether this life was the product of a second genesis — that is, whether its origin was independent of life on Earth. Earth and Mars are known to trade material in the form of rocks blasted from the planets' surfaces by the violent impacts of asteroids and comets. Microbes could have hitched a ride on this detritus, raising the possibility that life started on Earth and was transferred to Mars, or vice versa. If traces of past life were discovered on Mars but found to be identical to some form of terrestrial life, transportation by ejected rocks would be the most plausible explanation, and we would still lack evidence that life had started from scratch in two separate locations.

The significance of this point is crucial. In his theory of evolution Charles Darwin provided a persuasive account of how life evolved over billions of years, but he pointedly omitted any explanation of how life got started in the first place. "One might as well think of origin of matter," he wrote in a letter to a friend. A century and a half later, scientists still have little understanding of how the first living thing came to be.

Some scientists believe that life on Earth is a freak accident of chemistry, and as such must be unique. Because even the simplest known microbe is breathtakingly complex, they argue, the chances that one formed by blind molecular shuffling are infinitesimal; the probability that the process would occur twice, in separate locations, is virtually negligible. The French biochemist and Nobel laureate Jacques Monod was a firm believer in this view. "Man at last knows he is alone in the unfeeling immensity of the universe, out of which he has emerged only by chance," he wrote in 1971. He used this bleak assessment as a springboard to argue for atheism and the absurdity and pointlessness of existence. As Monod saw it, we are merely chemical extras in a majestic but impersonal cosmic drama — an irrelevant, unintended sideshow.

But suppose that's not what happened. Many scientists believe that life is not a freakish phenomenon (the odds of life's starting by chance, the British cosmologist Fred Hoyle once suggested, are comparable to the odds of a whirlwind's blowing through a junkyard and assembling a functioning Boeing 747) but instead is written into the laws of nature. "The universe must in some sense have known we were coming," the physicist Freeman Dyson famously observed. No one can say precisely in what sense the universe might be pregnant with life, or how the general expectancy Dyson spoke of might translate into specific physical processes at the molecular level. Perhaps matter and energy always get fast-tracked along the road to life by what's often called "self-organization." Or perhaps the power of Darwinian evolution is somehow harnessed at a pre-biotic molecular stage. Or maybe some efficient and as yet unidentified physical process (quantum mechanics?) sets the gears in motion, with organic life as we know it taking over the essential machinery at a later stage. Under any of these scenarios life becomes a fundamental rather than an incidental product of nature. In 1994, reflecting on this same point, another Nobel laureate, the Belgian biochemist Christian de Duve, wrote, "I view this universe not as a 'cosmic joke,' but as a meaningful entity — made in such a way as to generate life and mind, bound to give birth to thinking beings able to discern truth, apprehend beauty, feel love, yearn after goodness, define evil, experience mystery."

Absent from these accounts is any mention of miracles. Ascribing the origin of life to a divine miracle not only is anathema to scientists but also is theologically suspect. The term "Cod of the gaps" was coined to deride the notion that God can be invoked as an explanation whenever scientists have gaps in their understanding. The trouble with invoking God in this way is that as science advances, the gaps close, and God gets progressively squeezed out of the story of nature. Theologians long ago accepted that they would forever be fighting a rearguard battle if they tried to challenge science on its own ground. Using the formation of life to prove the existence of God is a tactic that risks instant demolition should someone succeed in making life in a test tube. And the idea that God acts in fits and starts, moving atoms around on odd occasions in competition with natural forces, is a decidedly uninspiring image of the Grand Architect.

The theological battle line in relation to the formation of life is not, therefore, between the natural and the miraculous but between sheer chance and lawlike certitude. Atheists tend to take the first side, and theists line up behind the second; but these divisions are general and by no means absolute. It's perfectly possible to be an atheist and believe that life is built ingeniously into the nature of the universe. It's also possible to be a theist and suppose that God engineered just one planet with life, with or without the help of miracles.

Though the discovery of microbes on Mars or elsewhere would ignite a passionate theological debate, the truly difficult issues surround the prospect of advanced alien beings in possession of intelligence and technology. Most scientists don't think that such beings exist, but for forty years a dedicated band of astronomers has been sweeping the skies with radio telescopes in hopes of finding a message from a civilization elsewhere in the galaxy. Their project is known as SETI (Search for Extraterrestrial Intelligence).

Because our solar system is relatively young compared with the universe overall, any alien civilization the SETI researchers might discover is likely to be much older, and presumably wiser, than ours. Indeed, it might have achieved our level of science and technology millions or even billions of years ago. Just contemplating the possibility of such advanced extraterrestrials appears to raise additional uncomfortable questions for religion.

The world's main faiths were all founded in the pre-scientific era, when Earth was widely believed to be at the center of the universe and humankind at the pinnacle of creation. As scientific discoveries have piled up over the past 500 years, our status has been incrementally diminished. First Earth was shown to be just one planet of several orbiting the Sun. Then the solar system itself was relegated to the outer suburbs of the galaxy, and the Sun classified as an insignificant dwarf star among billions. The theory of evolution proposed that human beings occupied just a small branch on a complex evolutionary tree. This pattern continued into the twentieth century, when the supremacy of our much vaunted intelligence came under threat. Computers began to outsmart us, Now genetic engineering has raised the specter of designer babies with superintellects that leave ours far behind. And we must consider the uncomfortable possibility that in astrobiological terms, God's children may be galactic also-rans.

Theologians are used to putting a brave face on such developments. Over the centuries the Christian church, for example, has time and again been forced to accommodate new scientific facts that challenge existing doctrine. But these accommodations have usually been made reluctantly and very belatedly. Only recently, for example, did the Pope acknowledge that Darwinian evolution is more than just a theory. If SETI succeeds, theologians will not have the luxury of decades of careful deliberation to assess the significance of the discovery. The impact will be instant.

The discovery of alien superbeings might not be so corrosive to religion if human beings could still claim special spiritual status. After all, religion is concerned primarily with people's relationship to God, rather than with their biological or intellectual qualities. It is possible to imagine alien beings who are smarter and wiser than we are but who are spiritually inferior, or just plain evil. However, it is more likely that any civilization that had surpassed us scientifically would have improved on our level of moral development, too. One may even speculate that an advanced alien society would sooner or later find some way to genetically eliminate evil behavior, resulting in a race of saintly beings.

Suppose, then, that E.T. is far ahead of us not only scientifically and technologically but spiritually, too. Where does that leave mankind's presumed special relationship with God? This conundrum poses a particular difficulty for Christians, because of the unique nature of the Incarnation. Of all the world's major religions, Christianity is the most species-specific Jesus Christ was humanity's savior and redeemer. He did not the for the dolphins or the gorillas, and certainly not for the proverbial little green men. But what of deeply spiritual aliens? Are they not to be saved? Can we contemplate a universe that contains perhaps a trillion worlds of saintly beings, but in which the only beings eligible for salvation inhabit a planet where murder, rape, and other evils remain rife?

Those few Christian theologians who have addressed this thorny issue divide into two camps. Some posit multiple incarnations and even multiple crucifixions — God taking on little green flesh to save little green men, as a prominent Anglican minister once told me. But most are appalled by this idea or find it ludicrous. After all, in the Christian view of the world, Jesus was God's only son. Would God have the same person born, killed, and resurrected in endless succession on planet after planet? This scenario was lampooned as long ago as 1794, by Thomas Paine. "The Son of God," he wrote in The Age of "Reason, "and sometimes God himself, would have nothing else to do than to travel from world to world, in an endless succession of death, with scarcely a momentary interval of life." Paine went on to argue that Christianity was simply incompatible with the existence of extraterrestrial beings, writing, "He who thinks he believes in both has thought but little of either."

Catholics tend to regard the idea of multiple incarnations as verging on heresy, not because of its somewhat comic aspect but because it would seem to automate an act that is supposed to be God's singular gift, "God chose a very specific way to redeem human beings," writes George Coyne, a Jesuit priest and the director of the Vatican Observatory, whose own research includes astrobiology. "He sent his only son, Jesus, to them, and Jesus gave up his life so that human beings would be saved from their sin. Did God do this for extraterrestrials? … The theological implications about God are getting ever more serious."

Paul Tillich, one of the few prominent Protestant theologians to give serious consideration to the issue of alien beings, took a more positive view. "Man cannot claim to occupy the only possible place for incarnation," he wrote. The Lutheran theologian Ted Peters, of the Center for Theology and the Natural Sciences, in Berkeley, California, has made a special study of the impact on religious faith of belief in extraterrestrials. In discussing the tradition of debate on this topic, he writes, "Christian theologians have routinely found ways to address the issue of Jesus Christ as God incarnate and to conceive of God's creative power and saving power exerted in other worlds." Peters believes that Christianity is robust enough and flexible enough to accommodate the discovery of extraterrestrial intelligence, or ETI. One theologian who is emphatically not afraid of that challenge is Robert Russell, also of the Center for Theology and the Natural Sciences. "As we await 'first contact,'" he has written, "pursuing these kinds of questions and reflections will be immensely valuable."

Clearly, there is considerable diversity — one might even say muddle — on this topic in theological circles. Ernan McMullin, a professor emeritus of philosophy at Notre Dame University, affirms that the central difficulty stems from Christianity's roots in a pre-scientific cosmology. "It was easier to accept the idea of God's becoming man," he has written, "when humans and their abode both held a unique place in the universe." He acknowledges that Christians especially face a stark predicament in relation to ETI, but feels that Thomas Paine and his like-minded successors have presented the problem too simplistically. Pointing out that concepts such as original sin, incarnation, and salvation are open to a variety of interpretations, McMullin concludes that there is also widespread divergence among Christians on the correct response to the ETI challenge. On the matter of multiple incarnations he writes, "Their answers could range … from 'yes, certainly' to 'certainly not.' My own preference would be a cautious 'maybe.'"

Even for those Christians who dismiss the idea of multiple incarnations there is an interesting fallback position: perhaps the course of evolution has an element of directionality, with humanlike beings the inevitable end product Even if Homo sapiens as such may not be the unique focus of God's attention, the broader class of all humanlike beings in the universe might be. This is the basic idea espoused by the philosopher Michael Ruse, an ardent Darwinian and an agnostic sympathetic to Christianity. He sees the incremental progress of natural evolution as God's chosen mode of creation, and the history of life as a ladder that leads inexorably from microbes to man.

Most biologists regard a "progressive evolution," with human beings its implied preordained goal, as preposterous. Stephen Jay Gould once described the very notion as "noxious," After all, the essence of Darwinism is that nature is blind. It cannot look ahead. Random chance is the driving force of evolution, and randomness by definition has no directionality. Gould insisted that if the evolutionary tape were replayed, the result would be very different from what we now observe. Probably life would never get beyond microbes next time around.

But some respected biologists disagree sharply with Gould on this point. Christian de Duve does not deny that the fine details of evolutionary history depend on happenstance, but he believes that the broad thrust of evolutionary change is somehow innately predetermined — that plants and animals were almost destined to emerge amid a general advance in complexity. Another Darwinian biologist, Simon Conway Morris, of Cambridge University, makes his own case for a "ladder of progress," invoking the phenomenon of convergent evolution — the tendency of similar-looking organisms to evolve independently in similar ecological niches. For example, the Tasmanian tiger (now extinct) played the role of the big cat in Australia even though, as a marsupial, it was genetically far removed from placental mammals. Like Ruse, Conway Morris maintains that the "humanlike niche" is likely to be filled on other planets that have advanced life. He even goes so far as to argue that extraterrestrials would have a humanoid form. It is not a great leap from this conclusion to the belief that extraterrestrials would sin, have consciences, struggle with ethical questions, and fear death.

The theological difficulties posed by the possibility of advanced alien beings are less acute for Judaism and Islam. Muslims, at least, are prepared for ETI: the Koran states explicitly, "And among His Signs is the creation of the heavens and the earth, and the living creatures that He has scattered through them." Nevertheless, both religions stress the specialness of human beings — and, indeed, of specific, well-defined groups who have been received into the faith. Could an alien become a Jew or a Muslim? Does the concept even make sense? Among the major religious communities, Buddhists and Hindus would seem to be the least threatened by the prospect of advanced aliens, owing to their pluralistic concept of God and their traditionally much grander vision of the cosmos.

Among the world's minority religions, some would positively welcome the discovery of intelligent aliens. The Raëlians, a Canada-based cult recently propelled to fame by its claim to have cloned a human being, believe that the cult's leader, Raël, a French former journalist originally named Claude Vorilhon, received revelations from aliens who briefly transported him inside a flying saucer in 1973. Other fringe religious organizations with an extraterrestrial message include the ill-fated Heaven's Gate cult and many UFO groups. Their adherents share a belief that aliens are located further up not only the evolutionary ladder but also the spiritual ladder, and can therefore help us draw closer to God and salvation. It is easy to dismiss such beliefs as insignificant to serious theological debate, but if evidence for alien beings were suddenly to appear, these cults might achieve overnight prominence while established religions floundered in doctrinal bewilderment.

Ironically, SETI is often accused of being a quasi-religious quest. But Jill Tarter, the director of the SETI Institute's Center for SETI Research, in Mountain View, California, has no truck with religion and is contemptuous of the theological gymnastics with which religious scholars accommodate the possibility of extraterrestrials. "God is our own invention," she has written. "If we're going to survive or turn into a long-lived technological civilization, organized religion needs to be outgrown. If we get a message [from an alien civilization] and it's secular in nature, I think that says that they have no organized religion — that they've outgrown it."

Tartar's dismissal is rather naive, however. Though many religious movements have come and gone throughout history, some sort of spirituality seems to be part of human nature. Even atheistic scientists profess to experience what Albert Einstein called a "cosmic religious feeling" when contemplating the awesome majesty of the universe.

Would advanced alien beings share this spiritual dimension, even though they might long ago have "outgrown" established religion? Steven Dick, a science historian at the U.S. Naval Observatory; believes they would. Dick is an expert on the history of speculation about extraterrestrial life, and he suggests that mankind's spirituality would be greatly expanded and enriched by contact with an alien civilization. However, he envisages that our present concept of God would probably require a wholesale transformation. Dick has outlined what he calls a new "cosmotheology," in which human spirituality is placed in a full cosmological and astrobiological context "As we learn more about our place in the universe," he has written, "and as we physically move away from our home planet, our cosmic consciousness will only increase." Dick proposes abandoning the transcendent God of monotheistic religion in favor of what he calls a "natural God"-a superbeing located within the universe and within nature. "With due respect for present religious traditions whose history stretches back nearly four millennia," he suggests, "the natural God of cosmic evolution and the biological universe, not the supernatural God of the ancient Near East, may be the God of the next millennium."

Some form of natural God was also proposed by Fred Hoyle, in a provocative book titled The Intelligent Universe. Hoyle drew on his work in astronomy and quantum physics to sketch the notion of a "superintellect" — a being who had, as Hoyle liked to say, "monkeyed with physics," adjusting the properties of the various fundamental particles and forces of nature so that carbon-based organisms could thrive and spread across the galaxy. Hoyle even suggested that this cosmic engineer might communicate with us by manipulating quantum processes in the brain. Most scientists shrug off Hoyle's speculations, but his ideas do show how far beyond traditional religious doctrine some people feel they need to go when they contemplate the possibility of advanced life forms beyond Earth.

Though in some ways the prospect of discovering extraterrestrial life undermines established religions, it is not all bad news for them. Astrobiology has also led to a surprising resurgence of the so-called "design argument" for the existence of God. The original design argument, as articulated by William Paley in the eighteenth century, was that living organisms' intricate adaptation to their environments pointed to the providential hand of a benign Creator. Darwin demolished the argument by showing how evolution driven by random mutation and natural selection could mimic design. Now a revamped design argument has emerged that fully embraces the Darwinian account of evolution and focuses instead on the origin of life. (I must stress that I am not referring here to what has recently become known as the Intelligent Design movement, which relies on an element of the miraculous.) If life is found to be widespread in the universe, the new design argument goes, then it must emerge rather easily from nonliving chemical mixtures, and thus the laws of nature must be cunningly contrived to unleash this remarkable and very special state of matter, which itself is a conduit to an even more remarkable and special state: mind. This sort of exquisite bio-friendliness would represent an extraordinary and unexpected bonus among nature's inventory of principles — one that could be interpreted by those of a religious persuasion as evidence of God's ingenuity and foresight. In this version of cosmic design, God acts not by direct intervention but by creating appropriate natural laws that guarantee the emergence of life and mind in cosmic abundance. The universe, in other words, is one in which there are no miracles except the miracle of nature itself.

The E.T. debate has only just begun, but a useful starting point is simply to acknowledge that the discovery of extraterrestrial life would not have to be theologically devastating. The revamped design argument offers a vision of nature distinctly inspiring to the spiritually inclined — certainly more so than that of a cosmos sterile everywhere but on a single planet. History is instructive in this regard. Four hundred years ago Giordano Bruno was burned at the stake by the Church in Rome for, among other things, espousing the notion of a plurality of inhabited worlds. To those whose theological outlook depended on a conception of Earth and its life forms as a singular miracle, the very notion of extraterrestrial life proved deeply threatening. But today the possibility of extraterrestrial life is anything but spiritually threatening. The more one accepts the formation of life as a natural process (that is, the more deeply embedded one believes it is in the overall cosmic scheme), the more ingenious and contrived (dare one say "designed"?) the universe appears to be.

The discovery of just a single bacterium somewhere beyond Earth would force us to rethink how we fit into the cosmic scheme of things, throwing us into a spiritual identity crisis as dramatic as the one brought about by Copernicus.

What about mankind's presumed special relationship with God? This is a conundrum for Christians. Jesus was humanity's savior and redeemer. He did not the for the dolphins or the gorillas, and certainly not for the proverbial little green men.

~~~~~~~~

By Paul Davies

15. Is there a case for viruses?

Section:

Special Report

Ideas: Sure, these bugs can infect a computer, but thye may have a positve side, too

BACTERIA GET A BAD PRESS. THEY CAUSE strep throat and ulcers. They rot food. A whole industry--hand soap--is devoted to their destruction. And yet, these cursed microbes have their moments. They make milk into cheese. As yeast, they make bread. Genetically engineered bacteria produce human insulin. The little buggers, it turns out, aren't always so bad.

Now the digital world has a parallel in a germ of its own: the computer virus. These rogue programs loom large in the public imagination as computer cannibals, bits of code released by mischievous or vengeful hackers that will attach to programs and eat data and discs alike. But viruses don't have to be bad. A few scientists have begun to argue that viruses are actually living organisms, capable someday of evolving into autonomous Net-runners that will retrieve information for their owners.

One of the leading exponents of the virus as-your-servant theory is Fred Cohen, a computer scientist and consultant. His 1984 Ph.D. thesis started the field of virus-security research. "A lot of the new technology that's being used to update networks is actually virus technology," he says, "but they don't use the word because it has other, negative connotations." In his book "It's Alive," Cohen describes networks into which he's released LPs, or live programs, to perform several different types of housekeeping tasks. They distribute software and clean out old files. Cohen suggests that LPs could even gather information from multiple databases.

In the most radical view, viruses are an artificial life form. They live, breed, evolve, procreate and die. Genetic algorithms--segments of programs that allow computer code to change its own form over a reproductive iteration--are not new to computing. But such algorithms can be paired with another program called a Reaper that kills older and damaged programs. Put the two together and you get a pretty good model of evolution.

That's how a kind of virus "game preserve" called Tierra works. Developed by Tom Ray, a University of Delaware ecologist, Tierra provides an environment in which self-replicating programs--viruses--compete for resources and evolve. Unlike the real world, inside Tierra tiny changes in a program don't usually result in terminal errors. This tolerance lets the programs evolve in unpredictable ways, such as the development of smaller parasites that reproduce by using other viruses' programming. That electronic biodiversity led Ray to propose seeding the entire Internet with progenitor viruses. He hopes that when faced with the richness of the Net, they'll become more complex. Eventually they'd evolve into useful applications, and users of the network could domesticate them.

These utopian visions aren't likely to come about any time soon. In fact, viruses of the type found in "the wild," on working computers, are becoming of a threat. Right now their primary mode of transmission is still the diskette. Infections move and outbreaks cluster around their points of for the first few months. That gives researchers a chance to parse the viruses and defeat them.

But the connectivity of computers on networks--such as the Internet--increases the danger. Jeff Kephart and fellow virus experts at IBM's Watson Research Center are developing an "automated immune system," software that captures viruses, analyzes them and spreads information on killing them along a network.

Ultimately, there's the viral Frankenstein issue: if they're alive, will viruses outrun human control? Consider the trajectory of the first viruses, the "worms" at the famed Xerox Palo Alto Research Center of the 1970s. The worms worked PARC's computer network, fetching messages and running diagnostic tests. One night a PARC worm ran amok, madly duplicating itself, finally crashing the system. PARC shut down the network until a software vaccine was developed--a matter of hours. But what happens when these critters start evolving faster than vaccines can be written?

PHOTO: Golden retrievers: If computer viruses are really a new life form, they'll evolve into messengers who work the Internet.

16. most beautiful and most wonderful16.Most beautiful and most wonderful

“There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.” —Charles Darwin, the concluding sentence of Origin of Species

When Judge John E. Jones III handed down his definitive ruling on the “intelligent design” lawsuit in Dover, Pennsylvania, most people in the scientific community heaved a sigh of relief. They had found, unexpectedly, a judge with enough smarts to see through the theory that many scientists have taken to calling “creationism in a cheap tuxedo.” But, while our schools may be temporarily insulated from the encroachment of the pulpit into the biology lab, I couldn’t help wondering if this was really cause for celebration.

Yes, I’m disturbed by those Gallup polls showing that more Americans believe in angels than evolution, and I agree that education is the only solution. And yet, it seems to have done little to sway the debate so far. For nearly one hundred and fifty years, ever since Darwin first published The Origin of Species in England, the argument has boiled down to a facile binary between believing in a white-bearded man in the sky or believing that your great-grandfather was a monkey. The characterization of each, of course, is absurd. And therein lies the seductive appeal of “intelligent design theory” (IDT). It offers the tantalizing prospect of a middle way, the chance that one could have the ability to reason scientifically and still be afforded enough leeway to acknowledge the possibility of the transcendent. There’s just one problem. IDT isn’t science. So those Gallup polls may be disturbing but not half as disturbing as hearing smart, well-educated people struggle to refute it—and this is what keeps me from celebrating the Dover decision too much.

In recent months, I’ve heard people say that Darwin was the first to propose evolution (he certainly was not), grope for the right words to explain how his theory of evolution works (two words: “natural selection”), and struggle to allow for a way in which that all-important mechanism may be partially influenced by a higher power (there’s simply no evidence to suggest it is). How much of a legitimate victory can we claim, if even the supporters of evolutionary theory are woefully ill-educated or misinformed on the topic?

Worse still, many people who presumably are educated on the subject have chosen to sidestep the issue, rather than engage in this intellectual heavy-lifting. In a profile by A. O. Scott in the New York Times Magazine, for example, Vendela Vida, co-editor of the indy magazine The Believer, was quoted as saying, “We don’t just . . . start thinking about Darwinism just because George Bush happened to say something about it,” then offered up that a future issue would instead “have David Sedaris talking mostly about monkeys.” I’ve read Vida’s work, which is well-written, and talked with her on a few occasions, and she veritably exudes intelligence—so maybe the blame for this unfortunate pairing of statements belongs to the reporter. Nevertheless, it highlights a shocking dismissal by intellectuals of the potential damage that could be wrought by a few vigorous, well-organized religious conservatives.

First, George W. Bush didn’t just happen to say something about IDT. He endorsed teaching it in our schools. He cloaked it in the language of free and open discourse—saying that it should be taught “so people can understand what the debate is about”—but that’s clearly a smoke screen. This isn’t about weighing competing theories; it’s about ignoring the facts. We don’t teach flat-earth theory in geology classes or teach that the earth is the center of the universe in astronomy; we shouldn’t be teaching creationism or IDT in the biology classroom either. But disregarding Bush’s statement as some off-handed remark seriously underestimates the importance of the message he is sending. This was an official endorsement—and it has helped drive this controversy and win new supporters for IDT. Like it or not, the presidency remains a bully pulpit, and such comments cannot be allowed to go unchallenged.

Second, reading David Sedaris on monkeys may be a pleasant diversion, but it doesn’t solve the problem—and this is what worries me most. We can’t afford to smile knowingly and skirt this issue. Just as importantly, we can’t take evolution on faith. Winning this argument requires knowing the facts. Not unsupported assertions, on either side, but facts. If we don’t know the basic narrative of Darwin’s life and work, then we leave our schools vulnerable. If we don’t know what advances have been made since then or how the scientific community continues to test and update Darwin’s theory, then we have brought IDT one step closer to the classroom. If we don’t bother to study the tenets of IDT, to scrutinize them and understand their flaws, then we can expect our children and grandchildren to be studying them as fact.

So, the long portfolio that begins this issue is quite simple. We have sought out the leading experts to address this topic in full. Esteemed science writer David Quammen writes about how Darwin came to write The Origin of Species and analyzes the original text. Niles Eldredge, curator of paleontology at the American Museum of Natural History and the living heir to Darwin, explains how he came to make one of the twentieth century’s most important adjustments to Darwin’s theory and discusses the deep respect he feels for Darwin as a thinker. Michael Ruse, who has spent more than twenty-five years debunking creationism and fighting to keep it out of our classrooms, explains the origins and flaws of IDT.

Last but not least, we present two short pieces by practicing scientists who examine two very specific problems: Thomas Eisner examines the scales on the wings of butterflies and moths, and Robert M. Sapolsky discusses the olfactory abilities of humans compared to other primates. Many people scoff when they learn that scientists are engaged in the study of such minutiae. But Eisner and Sapolsky show not only how much there is to be learned from such study, but also how much wonder lies in the incredible diversity and durability of life on our planet.

There is no need to view evolution as cold and heartless. To imagine life as an endlessly branching series of alternatives selected not by chance but by the chance elements of their moment, is not an expression of chaos or insignificance. It is a celebration of our matchless individuality, a recognition that nature’s rich variety not only makes each of us splendidly unique, but also that that singularity may allow us collectively to endure.

This knowledge, to me, seems a gift. There is grandeur in this view of life.

17 a final thought on intelligent design

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18.Mr. Dramin’s abominable volume

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