Very Important Logical Fallacies paper

When we reason, we (presumably) strive to reason correctly, so one of the centraltasks of logic is to identify the ways in which we are tempted to reasonincorrectly. One reasons incorrectly when the premises of an argument fail tosupport its conclusion, and arguments of that sort may be called fallacious. So ina very general sense, any error in reasoning is a fallacy. Similarly, any mistakenidea or false belief may sometimes be labeled “fallacious.”Logicians, however, commonly use the term “fallacy” more narrowly, todesignate not just any error in reasoning, but typical errors—mistakes in reason-ing that exhibit a pattern that can be identified and named. The great logician Gottlob Frege observed that it is one of the logician’s tasks to “indicate thepitfalls laid by language in the way of the thinker.” In this book we will use theterm in this way. In this narrower sense, each fallacy is a type of incorrect argument. Of course, many different arguments may make an error of some given type; that is, it may exhibit the same kind of mistake in reasoning. Any argument that does exhibit thatkind of mistake is said to commit that fallacy. The particular argument that com-mits some known fallacy is commonly said to be a fallacy, because it is an indi-vidual example of that typical mistake.To illustrate: If one accepts the premise that all science is essentially mate-rialistic and then goes on to argue that Karl Marx, a very influential philoso-pher of the nineteenth century who was certainly a materialist, musttherefore have been scientific, one reasons badly. It may indeed be true thatMarx was scientific (as he claimed to be), but it does not follow from the factthat he was a materialist (which he certainly was) that he was scientific. The bad reasoning here is fallacious. If every P is a Q, it does not follow from thefact that one is a Q that one is a P. All dogs are mammals, but not every mam-mal is a dog. What is identified here is a pattern of mistake; it is a very com-mon mistake that we will explore in detail in Chapter 8. Because that patternof error, or fallacy, appears in many different contexts, it is flagged, and la-beled: “the fallacy of affirming the consequent.” The argument concerningKarl Marx is a fallacy because it commits that fallacy, and the fallacy it commits. is the fallacy of affirming the consequent. This is independent of the equivo-cation in the use of the term “materialist,” which means different things inscience and in Marxism.In this illustration the mistake that has been made is called a formal fallacy; itis a pattern of mistake that appears in deductive arguments of a certain specifi-able form. There are other formal fallacies, and we shall examine them inChapter 8. Most fallacies, however, are not formal but informal: They are pat-terns of mistake that are made in the everyday uses of language. Informal falla-cies, which we examine very closely in this chapter, arise from confusionsconcerning the content of the language used. There is no limit to the variety offorms in which that content may appear, and thus informal fallacies are oftenmore difficult to detect than formal ones. It is language that deceives us here; wemay be tricked by inferences that seem plausible on the surface but that are in re-ality not warranted. Such traps, the “pitfalls” that language sets, can be avoidedif the patterns of those mistakes are well understood. Considerable attention willbe devoted to these informal fallacies—the kinds of mistakes made in everydayspeaking and writing, and commonly encountered, for example, in the “letters tothe editor” in daily newspapers. These are the logical mistakes that we will nameand explain. Because language is slippery and imprecise, we must be cautious in this en-terprise. Of course we must be careful not to make the mistakes in question, butwe must also be careful to refrain from accusing others of making mistakes whenthey do not really do so. If we encounter an argument that appears to be falla-cious, we must ask ourselves what really was meant by terms being used. The ac-cusation of fallacy is sometimes unjustly leveled at a passage intended by itsauthor to make a point that the critic has missed—perhaps even to make a joke.As patterns of mistakes in spoken and written language are identified, the typeof language used needs to be understood. Our logical standards should be high,but our application of those standards to arguments in ordinary life should alsobe generous and fair. Informal fallacies are numerous and can therefore be best understood if they aregrouped into categories, each with clearly identifiable features. This classifica-tion of fallacies is a controversial matter in logic. There is no one correct taxono-my of fallacies. Logicians have proposed lists of fallacies that vary greatly inlength; different sets have been specified, and different names have been given toboth the sets and the individual fallacies. Any classification of the kind that willfollow here is bound to be arbitrary in some degree. Our aim is to provide a com-prehensive scheme within which the most common informal fallacies can behelpfully identified—and avoided.The outline of this classification appears immediately below. After present-ing it, we will examine each group, and each individual fallacy, in detail. Fallacies of relevance are bald mistakes; they might better be called fallacies ofirrelevance, because they arise when there is no real connection between thepremises and the conclusion of an argument. Because that connection is miss-ing, the premises offered cannot possibly establish the truth of the conclusiondrawn. Of course, the premises may still be psychologically relevant, in that theymay evoke attitudes likely to cause the acceptance of the conclusion. The mis-take arises when some emotive features of language are used to support thetruth of a claim for which no objective reasons have been given. The modernnames of these fallacies are used here, but many of them have traditional namesas well (usually in Latin), which will also be included. Seven fallacies of rele-vance are of principal interest.R1. The Appeal to the Populace (Argumentum ad Populum)This fallacy is sometimes defined as the fallacy committed in making an emo-tional appeal; but this definition is so broad as to include most of the fallacies ofrelevance. It is defined more narrowly as the attempt to win popular assent to aconclusion by arousing the feelings of the multitude. The argument ad populum(“to the populace”) is the baldest of all fallacies, and yet it is one of the mostcommon. It is the instrument on which every demagogue and propagandist re-lies when faced with the task of mobilizing public sentiment. It is a fallacy be-cause, instead of evidence and rational argument, the speaker (or writer) relieson expressive language and other devices calculated to excite enthusiasm for oragainst some cause. Patriotism is one common cause about which it is easy to stiremotions, and we know that terrible abuses and injustices have been perpetratedin the name of patriotism. The oratory of Adolf Hitler, whipping up the racist en-thusiasms of his German listeners, is a classic example. Love of country is anhonorable emotion, but the appeal to that emotion in order to manipulate andmislead one’s audience is intellectually disreputable. “Patriotism,” Samuel John-son observed, “is the last refuge of a scoundrel.”The patriotic argument may be used when the national cause is good and theargument’s author is no scoundrel. An emotional defense of belief lacks intellec-tual merit, but the conclusion of that bad argument may be supportable by otherpremises of a more rational sort. Still, offered as the premises of an argument,sheer emotion is fallacious. On 23 March 1775 the Virginia House of Burgessespassed a resolution delivering Virginia’s troops to the Revolutionary War. TheHouse was spurred to adopt this resolution by an oration whose emotional con-tent has rarely been exceeded. Patrick Henry concluded this famous speech withthe following appeal: 9. In that melancholy book, The Future of an Illusion, Dr. Freud, himself oneof the last great theorists of the European capitalist class, has stated withsimple clarity the impossibility of religious belief for the educated manof today.—John Strachey, The Coming Struggle for Power, 193310. The classic trap for any revolutionary is always “What’s your alterna-tive?” But even if you could provide the interrogator with a blueprint,this does not mean he would use it; in most cases he is not sincere inwanting to know.—Shulamith Firestone, The Dialectic of Sex: The Case for Feminist Revolution, 1970. The premises of the fallacious arguments described in the preceding section arenot relevant to the conclusions drawn. However, there are many fallacious argu-ments in which the premises are relevant and yet are wholly inadequate. Thesewe call fallacies of defective induction. What are asserted as premises simplydo not serve as good reasons to reach the conclusion drawn.D1. The Argument from Ignorance (Argumentumad Ignorantiam)Someone commits the fallacy argumentum ad ignorantiam if he or she argues thatsomething is true because it has not been proved false, or false because it has notbeen proved true. Just because some proposition has not yet been proved false,we are not entitled to conclude that it is true. The same point can be made in re-verse: If some proposition has not yet been proved true, we are not entitled toconclude that it is false. Many true propositions have not yet been proved true, ofcourse, just as many false propositions have not yet been proved false. The factthat we cannot now be confident rarely serves as a good reason to assert knowl-edge of falsity, or of truth. Such an inference is defective; the fallacy is called theargument from ignorance, or the argument ad ignorantiam. Ignorance sometimesobliges us to suspend judgment, assigning neither truth nor falsity to the propo-sition in doubt.As a current illustration, the great abolitionist, Frederick Douglass, will soonhave a memorial, now being built at the northwest corner of Central Park in NewYork City. Beneath an 8-foot statue of Douglass himself is planned a quilt in gran-ite, an array of squares that are supposed, in legend, to be part of a secret codeused along the Underground Railroad to aid slaves escaping from their southernowners. However, prominent historians now agree that there never was such acode. There is no surviving example of such a quilt, and there is not a single men-tion of quilting codes in any diaries or memoirs from that period. The designer of

the memorial, Algernon Miller, nevertheless insists that the quilt remain part ofthe memorial project. “No matter what anyone has to say,” argues Miller, “they[his scholarly critics] weren’t there in that particular moment.” Not knowing thatthe legend is false, he concludes that we are justified in presuming it true.The fallacious appeal to ignorance crops up in science when plausibleclaims are held to be false because evidence of their truth cannot be provided.There may be good reason for its absence: In archeology or in paleontology, forinstance, that evidence may have been destroyed over time. In astronomy or inphysics, the evidence desired may be so distant in space or in time that it isphysically unobtainable. The fact that some desired evidence has not beengathered does not justify the conclusion that an otherwise plausible claim isfalse.The argument from ignorance is particularly attractive to those who defendpropositions that are very doubtful, even far-fetched. Pseudo-scientists whomake unverifiable claims about psychic phenomena (for example, abouttelepathy, or about contact with the dead) may insist that the truth of theirclaims is supported by the fact that their critics have been unable to prove theirfalsehood.An argument from ignorance was confronted by Galileo, whose newly in-vented telescope, early in the seventeenth century, plainly revealed the moun-tains and valleys of the moon. In his day, the “truth” that the moon was a perfectcrystalline sphere was unquestioned; it had to be perfect because that was whatAristotle had taught. Confronted by the evidence the telescope revealed,Galileo’s Aristotelian opponents responded with an argument that seemed ir-refutable: Any apparent irregularities on the moon’s surface are filled in with acrystalline substance that is, of course, invisible! This hypothesis saved themoon’s perfection, was in accord with what Aristotle had taught—and could notbe proved false. This fallacy deserved ridicule. Galileo answered with anargumentum ad ignorantiam of his own, absurd enough to expose his critics: Themoon is not a perfect sphere, he replied, because there are surely crystalmountains—invisible!—rising high from its surface. Because my theological crit-ics cannot prove the claim false, we cannot conclude that such mountains are notthere!Whenever some great change is proposed, within an institution, or in societyat large, those threatened by it are likely to attack with an argument from igno-rance. How do we know it will work? How do we know that it is safe? We do notknow; and without the knowledge that it is workable and safe, we must notadopt the change proposed. To prove workability or safety in advance, however,is often impossible. The objection sometimes takes the form of questions thatsuggest (but do not assert) the most horrific outcomes. Some mistakes in everyday reasoning are the consequence of an unjustified assump-tion, often suggested by the way in which the argument is formulated. That sugges-tion may be deliberate, or the assumption may be only an oversight. In either case,the upshot is that the reader, the listener, and even the author of the passage may beled to assume the truth of some unproved and unwarranted proposition. Whensuch dubious propositions, buried in the argument, are crucial for the support ofthe conclusion, the argument is bad and can be very misleading. Arguments thatdepend on such unwarranted leaps are called fallacies of presumption.In fallacious arguments of this kind the premises may indeed be relevant tothe conclusion drawn, but that relevance is likely to flow from the tacit supposi-tion of what has not been given support and may even be unsupportable. Thepresumption often goes unnoticed. To expose such a fallacy it is therefore usuallysufficient to call attention to the smuggled assumption, or supposition, and to itsdoubtfulness or its falsity. Three common fallacies are included in this category.P1. AccidentCircumstances alter cases. A generalization that is largely true may not apply ina given case (or to some subcategory of cases) for good reasons. The reasons thegeneralization does not apply in those cases have to do with the special circum-stances, also called the “accidental” circumstances, of that case or those cases. Ifthese accidental circumstances are ignored, and we assume that the generaliza-tion applies universally, we commit the fallacy of accident.In the preceding section we explained the fallacy of converse accident, or hastygeneralization, the mistake of moving carelessly or too quickly to a generalizationthat the evidence does not support. Accident is the fallacy that arises when wemove carelessly or unjustifiably from a generalization to some particulars that itdoes not in fact cover.Experience teaches us that even generalizations that are widely applicableand very useful are likely to have exceptions for which we must be on guard. Forexample, there is a general principle in law that hearsay evidence—statementsmade by a third party outside court—may not be accepted as evidence in court;this is the “hearsay rule,” and it is a good rule. However, when the person whoseoral communications are reported is dead, or when the party reporting thehearsay in court does so in conflict with his own best interest, that rule may notapply. Indeed, there is hardly any rule or general principle that does not haveplausible exceptions, and we are likely to argue fallaciously if we reason on thesupposition that some rule applies universally.