Philosophy

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In his "Meditations on First Philosophy," René Descartes is reconsidering his entire system of beliefs. He wants to remove

any distraction from his senses, so he sits before a �re in his dressing gown, alone. Descartes hopes that by removing all

distractions he will be able to “demolish” any false beliefs or assumptions. He does this in an attempt to refute the Skeptics

who say that one cannot know anything with certainty. Descartes examines his beliefs to see whether they can be

doubted. Any belief he can doubt cannot be self-evidently true. Therefore, it cannot be a basic belief that can serve as the

foundation for the system of his other beliefs.

Descartes is concerned with whether or not we can be certain that things, including our "self", exist. He had a great

insight, that the thinking person must exist because they are thinking. This means that thinking is connected to our

existence tautologically, as a matter of logical necessity. Descartes' way of answering this question brings to mind many

questions regarding how the thinking mind is causally in�uenced or effected by the physical body, and vice versa, how the

thinking mind would be in�uenced or effected by the physical body.

Since Descartes was a mathematician, it is not surprising to �nd that he sometimes uses the metaphor of geometry. Just

as the Greeks systematized geometry by showing that complex theorems can be proven from a small set of axioms,

Descartes aims to systematize the entire system of his beliefs by �nding which ones can be proven and which can be

doubted.

Notice that in Unit 1, we discussed different kinds of arguments. When Descartes mentions metaphors and geometry, we

can say he is making an argument by analogy. He is structuring his argument in a point-by-point logical way, using axioms

and premises that lead to conclusions.

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PHILOSOPHY - René DescartesPHILOSOPHY - René Descartes

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NOTE: You will learn more about Descartes' "Meditations" in Unit 3, as well.

Meditation I

Of the Things of Which We May Doubt

From Descartes' Meditations on First Philosophy. Edited by David B. Manley and Charles S. Taylor using John Veitch

translation of 1901.

1. SEVERAL years have now elapsed since I �rst became aware that I had accepted, even from my youth, many false

opinions for true, and that consequently what I afterward based on such principles was highly doubtful; and from that

time I was convinced of the necessity of undertaking once in my life to rid myself of all the opinions I had adopted, and of

commencing anew the work of building from the foundation, if I desired to establish a �rm and abiding superstructure in

the sciences. But as this enterprise appeared to me to be one of great magnitude, I waited until I had attained an age so

mature as to leave me no hope that at any stage of life more advanced I should be better able to execute my design. On

this account, I have delayed so long that I should henceforth consider I was doing wrong were I still to consume in

deliberation any of the time that now remains for action. To-day, then, since I have opportunely freed my mind from all

cares [and am happily disturbed by no passions], and since I am in the secure possession of leisure in a peaceable

retirement, I will at length apply myself earnestly and freely to the general overthrow of all my former opinions.

2. But, to this end, it will not be necessary for me to show that the whole of these are false--a point, perhaps, which I shall

never reach; but as even now my reason convinces me that I ought not the less carefully to withhold belief from what is

not entirely certain and indubitable, than from what is manifestly false, it will be suf�cient to justify the rejection of the

whole if I shall �nd in each some ground for doubt. Nor for this purpose will it be necessary even to deal with each belief

individually, which would be truly an endless labor; but, as the removal from below of the foundation necessarily involves

the downfall of the whole edi�ce, I will at once approach the criticism of the principles on which all my former beliefs

rested.

3. All that I have, up to this moment, accepted as possessed of the highest truth and certainty, I received either from or

through the senses. I observed, however, that these sometimes misled us; and it is the part of prudence not to place

absolute con�dence in that by which we have even once been deceived.

4. But it may be said, perhaps, that, although the senses occasionally mislead us respecting minute objects, and such as are

so far removed from us as to be beyond the reach of close observation, there are yet many other of their informations

(presentations), of the truth of which it is manifestly impossible to doubt; as for example, that I am in this place, seated by

the �re, clothed in a winter dressing gown, that I hold in my hands this piece of paper, with other intimations of the same

nature. But how could I deny that I possess these hands and this body, and withal escape being classed with persons in a

state of insanity, whose brains are so disordered and clouded by dark bilious vapors as to cause them pertinaciously to

Questions to Consider

As you read the text, consider the following questions:

For Descartes, why can't the basis of knowledge be gained through sense experience?

Why can’t the evil genius deceive Descartes into doubting his own existence?

Why does Descartes believe that he (his “self”) is certainly distinct from his body?

Why does Descartes believe that he is not present to his body in the way that a sailor is

present in a ship?

What does Descartes think is the relation between his mind and his body?

Making Connections

How does the way that Descartes describes reason and knowledge relate to how Socrates used reason and argument in The Apology in Unit 1? Socrates wants to engage in dialogue with opponents who might argue for false or unjusti�ed opinions. Compare this to how Descartes responded to the skeptics in his time. Descartes describes the mind and the body as separate and different. Does his view compare with Russell’s discussion of “expanding the self”?

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assert that they are monarchs when they are in the greatest poverty; or clothed [in gold] and purple when destitute of any

covering; or that their head is made of clay, their body of glass, or that they are gourds? I should certainly be not less

insane than they, were I to regulate my procedure according to examples so extravagant.

5. Though this be true, I must nevertheless here consider that I am a man, and that, consequently, I am in the habit of

sleeping, and representing to myself in dreams those same things, or even sometimes others less probable, which the

insane think are presented to them in their waking moments. How often have I dreamt that I was in these familiar

circumstances, that I was dressed, and occupied this place by the �re, when I was lying undressed in bed? At the present

moment, however, I certainly look upon this paper with eyes wide awake; the head which I now move is not asleep; I

extend this hand consciously and with express purpose, and I perceive it; the occurrences in sleep are not so distinct as all

this. But I cannot forget that, at other times I have been deceived in sleep by similar illusions; and, attentively considering

those cases, I perceive so clearly that there exist no certain marks by which the state of waking can ever be distinguished

from sleep, that I feel greatly astonished; and in amazement I almost persuade myself that I am now dreaming.

6. Let us suppose, then, that we are dreaming, and that all these particulars--namely, the opening of the eyes, the motion

of the head, the forth- putting of the hands--are merely illusions; and even that we really possess neither an entire body

nor hands such as we see. Nevertheless it must be admitted at least that the objects which appear to us in sleep are, as it

were, painted representations which could not have been formed unless in the likeness of realities; and, therefore, that

those general objects, at all events, namely, eyes, a head, hands, and an entire body, are not simply imaginary, but really

existent. For, in truth, painters themselves, even when they study to represent sirens and satyrs by forms the most

fantastic and extraordinary, cannot bestow upon them natures absolutely new, but can only make a certain medley of the

Check Your Answer

Descartes is sure that our observations always lead to true beliefs.

(a) True

(b) False

The correct answer is (b) False

But it may be said, perhaps, that, although the senses occasionally mislead us respecting minute objects, and such as

are so far removed from us as to be beyond the reach of close observation, there are yet many other of their

informations (presentations), of the truth of which it is manifestly impossible to doubt; as for example, that I am in

this place, seated by the �re, clothed in a winter dressing gown, that I hold in my hands this piece of paper, with other

intimations of the same nature.

Check Your Answer

As Descartes sits by the �re, he is concerned with the possibility that:

(a) his senses might be deceiving him

(b) his dressing gown may not be real

(c) the paper he holds may not be real

(d) he might not be in the habit of sleeping

The correct answer is (a) his senses might be deceiving him.

as for example, that I am in this place, seated by the �re, clothed in a winter dressing gown, that I hold in my

hands this piece of paper, with other intimations of the same nature. But how could I deny that I possess these

hands and this body, and withal escape being classed with persons in a state of insanity, whose brains are so

disordered and clouded by dark bilious vapors as to cause them pertinaciously to assert that they are monarchs

when they are in the greatest poverty; or clothed [in gold] and purple when destitute of any covering; or that

their head is made of clay, their body of glass, or that they are gourds?

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members of different animals; or if they chance to imagine something so novel that nothing at all similar has ever been

seen before, and such as is, therefore, purely �ctitious and absolutely false, it is at least certain that the colors of which

this is composed are real. And on the same principle, although these general objects, viz. [a body], eyes, a head, hands, and

the like, be imaginary, we are nevertheless absolutely necessitated to admit the reality at least of some other objects still

more simple and universal than these, of which, just as of certain real colors, all those images of things, whether true and

real, or false and fantastic, that are found in our consciousness (cogitatio), are formed.

7. To this class of objects seem to belong corporeal nature in general and its extension; the �gure of extended things, their

quantity or magnitude, and their number, as also the place in, and the time during, which they exist, and other things of the

same sort.

8. We will not, therefore, perhaps reason illegitimately if we conclude from this that Physics, Astronomy, Medicine, and all

the other sciences that have for their end the consideration of composite objects, are indeed of a doubtful character; but

that Arithmetic, Geometry, and the other sciences of the same class, which regard merely the simplest and most general

objects, and scarcely inquire whether or not these are really existent, contain somewhat that is certain and indubitable:

for whether I am awake or dreaming, it remains true that two and three make �ve, and that a square has but four sides;

nor does it seem possible that truths so apparent can ever fall under a suspicion of falsity [or incertitude].

Check Your Answer

Descartes describes objects that are corporeal as having everything listed below EXCEPT:

(a) Extension

(b) Number

(c) Quantity

(d) The ability to think

The correct answer is (d) the ability to think.

To this class of objects seem to belong corporeal nature in general and its extension; the �gure of extended

things, their quantity or magnitude, and their number, as also the place in, and the time during, which they exist,

and other things of the same sort.

Check Your Answer

Two possible reasons our senses might deceive us are:

(a) we might be tired or we might be over stressed

(b) we might be dreaming or we might be deceived

(c) we might be overly emotional or insuf�ciently careful

(d) we might be lacking in faith or lacking in creativity

The correct answer is (b) we might be dreaming or we might be deceived.

We will not, therefore, perhaps reason illegitimately if we conclude from this that Physics, Astronomy, Medicine,

and all the other sciences that have for their end the consideration of composite objects, are indeed of a doubtful

character; but that Arithmetic, Geometry, and the other sciences of the same class, which regard merely the

simplest and most general objects, and scarcely inquire whether or not these are really existent, contain

somewhat that is certain and indubitable: for whether I am awake or dreaming, it remains true that two and

three make �ve, and that a square has but four sides; nor does it seem possible that truths so apparent can ever

fall under a suspicion of falsity [or incertitude].

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9. Nevertheless, the belief that there is a God who is all powerful, and who created me, such as I am, has, for a long time,

obtained steady possession of my mind. How, then, do I know that he has not arranged that there should be neither earth,

nor sky, nor any extended thing, nor �gure, nor magnitude, nor place, providing at the same time, however, for [the rise in

me of the perceptions of all these objects, and] the persuasion that these do not exist otherwise than as I perceive them ?

And further, as I sometimes think that others are in error respecting matters of which they believe themselves to possess

a perfect knowledge, how do I know that I am not also deceived each time I add together two and three, or number the

sides of a square, or form some judgment still more simple, if more simple indeed can be imagined? But perhaps Deity has

not been willing that I should be thus deceived, for he is said to be supremely good. If, however, it were repugnant to the

goodness of Deity to have created me subject to constant deception, it would seem likewise to be contrary to his

goodness to allow me to be occasionally deceived; and yet it is clear that this is permitted.

10. Some, indeed, might perhaps be found who would be disposed rather to deny the existence of a Being so powerful

than to believe that there is nothing certain. But let us for the present refrain from opposing this opinion, and grant that

all which is here said of a Deity is fabulous: nevertheless, in whatever way it be supposed that I reach the state in which I

exist, whether by fate, or chance, or by an endless series of antecedents and consequents, or by any other means, it is clear

(since to be deceived and to err is a certain defect ) that the probability of my being so imperfect as to be the constant

victim of deception, will be increased exactly in proportion as the power possessed by the cause, to which they assign my

origin, is lessened. To these reasonings I have assuredly nothing to reply, but am constrained at last to avow that there is

nothing of all that I formerly believed to be true of which it is impossible to doubt, and that not through thoughtlessness

or levity, but from cogent and maturely considered reasons; so that hence forward, if I desire to discover anything certain,

I ought not the less carefully to refrain from assenting to those same opinions than to what might be shown to be

manifestly false.

11. But it is not suf�cient to have made these observations; care must be taken likewise to keep them in remembrance.

For those old and customary opinions perpetually recur long and familiar usage giving them the right of occupying my

mind, even almost against my will, and subduing my belief; nor will I lose the habit of deferring to them and con�ding in

them so long as I shall consider them to be what in truth they are, viz, opinions to some extent doubtful, as I have already

shown, but still highly probable, and such as it is much more reasonable to believe than deny. It is for this reason I am

persuaded that I shall not be doing wrong, if, taking an opposite judgment of deliberate design, I become my own deceiver,

by supposing, for a time, that all those opinions are entirely false and imaginary, until at length, having thus balanced my

old by my new prejudices, my judgment shall no longer be turned aside by perverted usage from the path that may

conduct to the perception of truth. For I am assured that, meanwhile, there will arise neither peril nor error from this

course, and that I cannot for the present yield too much to distrust, since the end I now seek is not action but knowledge.

12. I will suppose, then, not that Deity, who is sovereignly good and the fountain of truth, but that some malignant demon,

who is at once exceedingly potent and deceitful, has employed all his arti�ce to deceive me; I will suppose that the sky, the

air, the earth, colors, �gures, sounds, and all external things, are nothing better than the illusions of dreams, by means of

which this being has laid snares for my credulity; I will consider myself as without hands, eyes, �esh, blood, or any of the

senses, and as falsely believing that I am possessed of these; I will continue resolutely �xed in this belief, and if indeed by

this means it be not in my power to arrive at the knowledge of truth, I shall at least do what is in my power, viz, [ suspend

my judgment], and guard with settled purpose against giving my assent to what is false, and being imposed upon by this

deceiver, whatever be his power and arti�ce. But this undertaking is arduous, and a certain indolence insensibly leads me

back to my ordinary course of life; and just as the captive, who, perchance, was enjoying in his dreams an imaginary liberty,

when he begins to suspect that it is but a vision, dreads awakening, and conspires with the agreeable illusions that the

deception may be prolonged; so I, of my own accord, fallback into the train of my former beliefs, and fear to arouse myself

from my slumber, lest the time of laborious wakefulness that would succeed this quiet rest, in place of bringing any light of

day, should prove inadequate to dispel the darkness that will arise from the dif�culties that have now been raised.

Check Your Answer

Descartes begins his search for the truth by using a method of doubt, saying:

(a) I will suppose that the Evil Demon can be driven away byfaith, prayer, and reason

(b) I will suppose that my dreams will lead me to real knowledge of the sky, the air, the earth, colors, �gures,

sounds, and all external things

(c) I will suppose that the sky, the air, the earth, colors, �gures, sounds, and all external things, are nothing better

than the illusions of dreams

(d) I will suppose that the sky, the air, the earth, colors, �gures, sounds, and all external things, are all reliable and

clear and distinct

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Meditation VI

Of the Existence of Material Things, and of the Real Distinction Between the Mind and Body of Man

From Descartes' Meditations on First Philosophy. Edited by David B. Manley and Charles S. Taylor using John Veitch

translation of 1901.

1. THERE now only   remains the inquiry as to whether material things exist. With regard to this question, I at least know

with certainty that such things may exist, in as far as they constitute the object of the pure mathematics, since, regarding

them in this aspect, I can conceive them clearly and distinctly. For there can be no doubt that God possesses the power of

producing all the objects I am able distinctly to conceive, and I never considered anything impossible to him, unless when I

experienced a contradiction in the attempt to conceive it aright. Further, the faculty of imagination which I possess, and of

which I am conscious that I make use when I apply myself to the consideration of material things, is suf�cient to persuade

me of their existence: for, when I attentively consider what imagination is, I �nd that it is simply a certain application of

the cognitive faculty ( facultas cognoscitiva) to a body which is immediately present to it, and which therefore exists.

2. And to render this quite clear, I remark, in the �rst place, the difference that subsists between imagination and pure

intellection [or conception ]. For example, when I imagine a triangle I not only conceive (intelligo) that it is a �gure

comprehended by three lines, but at the same time also I look upon (intueor) these three lines as present by the power

and internal application of my mind (acie mentis), and this is what I call imagining. But if I desire to think of a chiliogon, I

indeed rightly conceive that it is a �gure composed of a thousand sides, as easily as I conceive that a triangle is a �gure

composed of only three sides; but I cannot imagine the thousand sides of a chiliogon as I do the three sides of a triangle,

nor, so to speak, view them as present [with the eyes of my mind ]. And although, in accordance with the habit I have of

always imagining something when I think of corporeal things, it may happen that, in conceiving a chiliogon, I confusedly

represent some �gure to myself, yet it is quite evident that this is not a chiliogon, since it in no wise differs from that which

I would represent to myself, if I were to think of a myriogon, or any other �gure of many sides; nor would this

representation be of any use in discovering and unfolding the properties that constitute the difference between a

chiliogon and other polygons. But if the question turns on a pentagon, it is quite true that I can conceive its �gure, as well

as that of a chiliogon, without the aid of imagination; but I can likewise imagine it by applying the attention of my mind to

its �ve sides, and at the same time to the area which they contain. Thus I observe that a special effort of mind is necessary

to the act of imagination, which is not required to conceiving or understanding (ad intelligendum); and this special

exertion of mind clearly shows the difference between imagination and pure intellection (imaginatio et intellectio pura).

The correct answer is (c) I will suppose that the sky, the air, the earth, colors, �gures, sounds, and all external

things, are nothing better than the illusions of dreams.

I will suppose, then, not that Deity, who is sovereignly good and the fountain of truth, but that some malignant

demon, who is at once exceedingly potent and deceitful, has employed all his arti�ce to deceive me; I will

suppose that the sky, the air, the earth, colors, �gures, sounds, and all external things, are nothing better than the

illusions of dreams, by means of which this being has laid snares for my credulity.

Check Your Answer

Descartes says he is able to clearly and distinctly conceive one thing apart from another because:

(a) he knows that all which he clearly and distinctly conceives canbe produced by God exactly as he conceives it

(b) he is being given clear and distinct perceptions by his dreams

(c) he is being given clear and distinct perceptions by an evil demon

(d) he is being given clear and distinct sensory perceptions that are veri�ed by his reason

The correct answer is (a) he knows that all which he clearly and distinctly conceives canbe produced by God

exactly as he conceives it

Nature likewise teaches me by these sensations of pain, hunger, thirst, etc., that I am not only lodged in my body

as a pilot in a vessel, but that I am besides so intimately conjoined, and as it were intermixed with it, that my mind

and body compose a certain unity.

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3. I remark, besides, that this power of imagination which I possess, in as far as it differs from the power of conceiving, is in

no way necessary to my [nature or] essence, that is, to the essence of my mind; for although I did not possess it, I should

still remain the same that I now am, from which it seems we may conclude that it depends on something different from the

mind. And I easily understand that, if some body exists, with which my mind is so conjoined and united as to be able, as it

were, to consider it when it chooses, it may thus imagine corporeal objects; so that this mode of thinking differs from pure

intellection only in this respect, that the mind in conceiving turns in some way upon itself, and considers some one of the

ideas it possesses within itself; but in imagining it turns toward the body, and contemplates in it some object conformed to

the idea which it either of itself conceived or apprehended by sense. I easily understand, I say, that imagination may be

thus formed, if it is true that there are bodies; and because I �nd no other obvious mode of explaining it, I thence, with

probability, conjecture that they exist, but only with probability; and although I carefully examine all things, nevertheless I

do not �nd that, from the distinct idea of corporeal nature I have in my imagination, I can necessarily infer the existence of

any body.

4. But I am accustomed to imagine many other objects besides that corporeal nature which is the object of the pure

mathematics, as, for example, colors, sounds, tastes, pain, and the like, although with less distinctness; and, inasmuch as I

perceive these objects much better by the senses, through the medium of which and of memory, they seem to have

reached the imagination, I believe that, in order the more advantageously to examine them, it is proper I should at the

same time examine what sense-perception is, and inquire whether from those ideas that are apprehended by this mode of

thinking ( consciousness), I cannot obtain a certain proof of the existence of corporeal objects.

5. And, in the �rst place, I will recall to my mind the things I have hitherto held as true, because perceived by the senses,

and the foundations upon which my belief in their truth rested; I will, in the second place, examine the reasons that

afterward constrained me to doubt of them; and, �nally, I will consider what of them I ought now to believe.

6. Firstly, then, I perceived that I had a head, hands, feet and other members composing that body which I considered as

part, or perhaps even as the whole, of myself. I perceived further, that that body was placed among many others, by which

it was capable of being affected in diverse ways, both bene�cial and hurtful; and what was bene�cial I remarked by a

certain sensation of pleasure, and what was hurtful by a sensation of pain. And besides this pleasure and pain, I was

likewise conscious of hunger, thirst, and other appetites, as well as certain corporeal inclinations toward joy, sadness,

anger, and similar passions. And, out of myself, besides the extension, �gure, and motions of bodies, I likewise perceived in

them hardness, heat, and the other tactile qualities, and, in addition, light, colors, odors, tastes, and sounds, the variety of

which gave me the means of distinguishing the sky, the earth, the sea, and generally all the other bodies, from one another.

And certainly, considering the ideas of all these qualities, which were presented to my mind, and which alone I properly

and immediately perceived, it was not without reason that I thought I perceived certain objects wholly different from my

thought, namely, bodies from which those ideas proceeded; for I was conscious that the ideas were presented to me

without my consent being required, so that I could not perceive any object, however desirous I might be, unless it were

present to the organ of sense; and it was wholly out of my power not to perceive it when it was thus present. And because

the ideas I perceived by the senses were much more lively and clear, and even, in their own way, more distinct than any of

those I could of myself frame by meditation, or which I found impressed on my memory, it seemed that they could not

have proceeded from myself, and must therefore have been caused in me by some other objects; and as of those objects I

had no knowledge beyond what the ideas themselves gave me, nothing was so likely to occur to my mind as the

supposition that the objects were similar to the ideas which they caused. And because I recollected also that I had

formerly trusted to the senses, rather than to reason, and that the ideas which I myself formed were not so clear as those I

perceived by sense, and that they were even for the most part composed of parts of the latter, I was readily persuaded

that I had no idea in my intellect which had not formerly passed through the senses. Nor was I altogether wrong in

likewise believing that that body which, by a special right, I called my own, pertained to me more properly and strictly than

any of the others; for in truth, I could never be separated from it as from other bodies; I felt in it and on account of it all my

appetites and affections, and in �ne I was affected in its parts by pain and the titillation of pleasure, and not in the parts of

the other bodies that were separated from it. But when I inquired into the reason why, from this I know not what

sensation of pain, sadness of mind should follow, and why from the sensation of pleasure, joy should arise, or why this

indescribable twitching of the stomach, which I call hunger, should put me in mind of taking food, and the parchedness of

the throat of drink, and so in other cases, I was unable to give any explanation, unless that I was so taught by nature; for

there is assuredly no af�nity, at least none that I am able to comprehend, between this irritation of the stomach and the

desire of food, any more than between the perception of an object that causes pain and the consciousness of sadness

which springs from the perception. And in the same way it seemed to me that all the other judgments I had formed

regarding the objects of sense, were dictates of nature; because I remarked that those judgments were formed in me,

before I had leisure to weigh and consider the reasons that might constrain me to form them.

7. But, afterward, a wide experience by degrees sapped the faith I had reposed in my senses; for I frequently observed

that towers, which at a distance seemed round, appeared square, when more closely viewed, and that colossal �gures,

raised on the summits of these towers, looked like small statues, when viewed from the bottom of them; and, in other

instances without number, I also discovered error in judgments founded on the external senses; and not only in those

founded on the external, but even in those that rested on the internal senses; for is there aught more internal than pain ?

And yet I have sometimes been informed by parties whose arm or leg had been amputated, that they still occasionally

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seemed to feel pain in that part of the body which they had lost, --a circumstance that led me to think that I could not be

quite certain even that any one of my members was affected when I felt pain in it. And to these grounds of doubt I shortly

afterward also added two others of very wide generality: the �rst of them was that I believed I never perceived anything

when awake which I could not occasionally think I also perceived when asleep, and as I do not believe that the ideas I seem

to perceive in my sleep proceed from objects external to me, I did not any more observe any ground for believing this of

such as I seem to perceive when awake; the second was that since I was as yet ignorant of the author of my being or at

least supposed myself to be so, I saw nothing to prevent my having been so constituted by nature as that I should be

deceived even in matters that appeared to me to possess the greatest truth. And, with respect to the grounds on which I

had before been persuaded of the existence of sensible objects, I had no great dif�culty in �nding suitable answers to

them; for as nature seemed to incline me to many things from which reason made me averse, I thought that I ought not to

con�de much in its teachings. And although the perceptions of the senses were not dependent on my will, I did not think

that I ought on that ground to conclude that they proceeded from things different from myself, since perhaps there might

be found in me some faculty, though hitherto unknown to me, which produced them.

8. But now that I begin to know myself better, and to discover more clearly the author of my being, I do not, indeed, think

that I ought rashly to admit all which the senses seem to teach, nor, on the other hand, is it my conviction that I ought to

doubt in general of their teachings.

9. And, �rstly, because I know that all which I clearly and distinctly conceive can be produced by God exactly as I conceive

it, it is suf�cient that I am able clearly and distinctly to conceive one thing apart from another, in order to be certain that

the one is different from the other, seeing they may at least be made to exist separately, by the omnipotence of God; and it

matters not by what power this separation is made, in order to be compelled to judge them different; and, therefore,

merely because I know with certitude that I exist, and because, in the meantime, I do not observe that aught necessarily

belongs to my nature or essence beyond my being a thinking thing, I rightly conclude that my essence consists only in my

being a thinking thing [or a substance whose whole essence or nature is merely thinking]. And although I may, or rather, as

I will shortly say, although I certainly do possess a body with which I am very closely conjoined; nevertheless, because, on

the one hand, I have a clear and distinct idea of myself, in as far as I am only a thinking and unextended thing, and as, on the

other hand, I possess a distinct idea of body, in as far as it is only an extended and unthinking thing, it is certain that I, [that

is, my mind, by which I am what I am], is entirely and truly distinct from my body, and may exist without it.

10. Moreover, I �nd in myself diverse faculties of thinking that have each their special mode: for example, I �nd I possess

the faculties of imagining and perceiving, without which I can indeed clearly and distinctly conceive myself as entire, but I

cannot reciprocally conceive them without conceiving myself, that is to say, without an intelligent substance in which they

reside, for [in the notion we have of them, or to use the terms of the schools] in their formal concept, they comprise some

sort of intellection; whence I perceive that they are distinct from myself as modes are from things. I remark likewise

certain other faculties, as the power of changing place, of assuming diverse �gures, and the like, that cannot be conceived

and cannot therefore exist, any more than the preceding, apart from a substance in which they inhere. It is very evident,

however, that these faculties, if they really exist, must belong to some corporeal or extended substance, since in their

clear and distinct concept there is contained some sort of extension, but no intellection at all. Further, I cannot doubt but

that there is in me a certain passive faculty of perception, that is, of receiving and taking knowledge of the ideas of

sensible things; but this would be useless to me, if there did not also exist in me, or in some other thing, another active

faculty capable of forming and producing those ideas. But this active faculty cannot be in me [in as far as I am but a

thinking thing], seeing that it does not presuppose thought, and also that those ideas are frequently produced in my mind

without my contributing to it in any way, and even frequently contrary to my will. This faculty must therefore exist in some

substance different from me, in which all the objective reality of the ideas that are produced by this faculty is contained

Check Your Answer

Descartes notes that his mind is extended and thinking, and his body is unextended and thinking.

(a) True

(b) False

The correct answer is (b) False.

I will shortly say, although I certainly do possess a body with which I am very closely conjoined; nevertheless,

because, on the one hand, I have a clear and distinct idea of myself, in as far as I am only a thinking and

unextended thing, and as, on the other hand, I possess a distinct idea of body, in as far as it is only an extended

and unthinking thing, it is certain that I, [that is, my mind, by which I am what I am], is entirely and truly distinct

from my body, and may exist without it.

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formally or eminently, as I before remarked; and this substance is either a body, that is to say, a corporeal nature in which

is contained formally [and in effect] all that is objectively [and by representation] in those ideas; or it is God himself, or

some other creature, of a rank superior to body, in which the same is contained eminently. But as God is no deceiver, it is

manifest that he does not of himself and immediately communicate those ideas to me, nor even by the intervention of any

creature in which their objective reality is not formally, but only eminently, contained. For as he has given me no faculty

whereby I can discover this to be the case, but, on the contrary, a very strong inclination to believe that those ideas arise

from corporeal objects, I do not see how he could be vindicated from the charge of deceit, if in truth they proceeded from

any other source, or were produced by other causes than corporeal things: and accordingly it must be concluded, that

corporeal objects exist. Nevertheless, they are not perhaps exactly such as we perceive by the senses, for their

comprehension by the senses is, in many instances, very obscure and confused; but it is at least necessary to admit that all

which I clearly and distinctly conceive as in them, that is, generally speaking all that is comprehended in the object of

speculative geometry, really exists external to me.

11. But with respect to other things which are either only particular, as, for example, that the sun is of such a size and

�gure, etc., or are conceived with less clearness and distinctness, as light, sound, pain, and the like, although they are

highly dubious and uncertain, nevertheless on the ground alone that God is no deceiver, and that consequently he has

permitted no falsity in my opinions which he has not likewise given me a faculty of correcting, I think I may with safety

conclude that I possess in myself the means of arriving at the truth. And, in the �rst place, it cannot be doubted that in

each of the dictates of nature there is some truth: for by nature, considered in general, I now understand nothing more

than God himself, or the order and disposition established by God in created things; and by my nature in particular I

understand the assemblage of all that God has given me.

12. But there is nothing which that nature teaches me more expressly [or more sensibly] than that I have a body which is

ill affected when I feel pain, and stands in need of food and drink when I experience the sensations of hunger and thirst,

etc. And therefore I ought not to doubt but that there is some truth in these informations.

13. Nature likewise teaches me by these sensations of pain, hunger, thirst, etc., that I am not only lodged in my body as a

pilot in a vessel, but that I am besides so intimately conjoined, and as it were intermixed with it, that my mind and body

compose a certain unity. For if this were not the case, I should not feel pain when my body is hurt, seeing I am merely a

thinking thing, but should perceive the wound by the understanding alone, just as a pilot perceives by sight when any part

of his vessel is damaged; and when my body has need of food or drink, I should have a clear knowledge of this, and not be

made aware of it by the confused sensations of hunger and thirst: for, in truth, all these sensations of hunger, thirst, pain,

etc., are nothing more than certain confused modes of thinking, arising from the union and apparent fusion of mind and

body.

14. Besides this, nature teaches me that my own body is surrounded by many other bodies, some of which I have to seek

after, and others to shun. And indeed, as I perceive different sorts of colors, sounds, odors, tastes, heat, hardness, etc., I

safely conclude that there are in the bodies from which the diverse perceptions of the senses proceed, certain varieties

corresponding to them, although, perhaps, not in reality like them; and since, among these diverse perceptions of the

senses, some are agreeable, and others disagreeable, there can be no doubt that my body, or rather my entire self, in as far

as I am composed of body and mind, may be variously affected, both bene�cially and hurtfully, by surrounding bodies.

Check Your Answer

Nature has taught Descartes that he is not merely lodged in his body as a ______________ but that he is intimately

conjoined with it and that his mind and body compose a certain unity.

(a) horse in a stable

(b) pilot in a vessel

(c) chicken in a pot

(d) light in a window

The correct answer is (b) pilot in a vessel.

Nature likewise teaches me by these sensations of pain, hunger, thirst, etc., that I am not only lodged in my body

as a pilot in a vessel, but that I am besides so intimately conjoined, and as it were intermixed with it, that my mind

and body compose a certain unity. 

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15. But there are many other beliefs which though seemingly the teaching of nature, are not in reality so, but which

obtained a place in my mind through a habit of judging inconsiderately of things. It may thus easily happen that such

judgments shall contain error: thus, for example, the opinion I have that all space in which there is nothing to affect [or

make an impression on] my senses is void: that in a hot body there is something in every respect similar to the idea of heat

in my mind; that in a white or green body there is the same whiteness or greenness which I perceive; that in a bitter or

sweet body there is the same taste, and so in other instances; that the stars, towers, and all distant bodies, are of the same

size and �gure as they appear to our eyes, etc. But that I may avoid everything like indistinctness of conception, I must

accurately de�ne what I properly understand by being taught by nature. For nature is here taken in a narrower sense than

when it signi�es the sum of all the things which God has given me; seeing that in that meaning the notion comprehends

much that belongs only to the mind [to which I am not here to be understood as referring when I use the term nature]; as,

for example, the notion I have of the truth, that what is done cannot be undone, and all the other truths I discern by the

natural light [ without the aid of the body]; and seeing that it comprehends likewise much besides that belongs only to

body, and is not here any more contained under the name nature, as the quality of heaviness, and the like, of which I do not

speak, the term being reserved exclusively to designate the things which God has given to me as a being composed of

mind and body. But nature, taking the term in the sense explained, teaches me to shun what causes in me the sensation of

pain, and to pursue what affords me the sensation of pleasure, and other things of this sort; but I do not discover that it

teaches me, in addition to this, from these diverse perceptions of the senses, to draw any conclusions respecting external

objects without a previous [ careful and mature ] consideration of them by the mind: for it is, as appears to me, the of�ce

of the mind alone, and not of the composite whole of mind and body, to discern the truth in those matters. Thus, although

the impression a star makes on my eye is not larger than that from the �ame of a candle, I do not, nevertheless, experience

any real or positive impulse determining me to believe that the star is not greater than the �ame; the true account of the

matter being merely that I have so judged from my youth without any rational ground. And, though on approaching the

�re I feel heat, and even pain on approaching it too closely, I have, however, from this no ground for holding that

something resembling the heat I feel is in the �re, any more than that there is something similar to the pain; all that I have

ground for believing is, that there is something in it, whatever it may be, which excites in me those sensations of heat or

pain. So also, although there are spaces in which I �nd nothing to excite and affect my senses, I must not therefore

conclude that those spaces contain in them no body; for I see that in this, as in many other similar matters, I have been

accustomed to pervert the order of nature, because these perceptions of the senses, although given me by nature merely

to signify to my mind what things are bene�cial and hurtful to the composite whole of which it is a part, and being

suf�ciently clear and distinct for that purpose, are nevertheless used by me as infallible rules by which to determine

immediately the essence of the bodies that exist out of me, of which they can of course afford me only the most obscure

and confused knowledge.

16. But I have already suf�ciently considered how it happens that, notwithstanding the supreme goodness of God, there is

falsity in my judgments. A dif�culty, however, here presents itself, respecting the things which I am taught by nature must

be pursued or avoided, and also respecting the internal sensations in which I seem to have occasionally detected error,

[and thus to be directly deceived by nature]: thus, for example, I may be so deceived by the agreeable taste of some viand

with which poison has been mixed, as to be induced to take the poison. In this case, however, nature may be excused, for it

simply leads me to desire the viand for its agreeable taste, and not the poison, which is unknown to it; and thus we can

infer nothing from this circumstance beyond that our nature is not omniscient; at which there is assuredly no ground for

surprise, since, man being of a �nite nature, his knowledge must likewise be of a limited perfection.

17. But we also not unfrequently err in that to which we are directly impelled by nature, as is the case with invalids who

desire drink or food that would be hurtful to them. It will here, perhaps, be alleged that the reason why such persons are

deceived is that their nature is corrupted; but this leaves the dif�culty untouched, for a sick man is not less really the

creature of God than a man who is in full health; and therefore it is as repugnant to the goodness of God that the nature of

the former should be deceitful as it is for that of the latter to be so. And as a clock, composed of wheels and counter

weights, observes not the less accurately all the laws of nature when it is ill made, and points out the hours incorrectly,

than when it satis�es the desire of the maker in every respect; so likewise if the body of man be considered as a kind of

machine, so made up and composed of bones, nerves, muscles, veins, blood, and skin, that although there were in it no

mind, it would still exhibit the same motions which it at present manifests involuntarily, and therefore without the aid of

the mind, [and simply by the dispositions of its organs], I easily discern that it would also be as natural for such a body,

supposing it dropsical, for example, to experience the parchedness of the throat that is usually accompanied in the mind

by the sensation of thirst, and to be disposed by this parchedness to move its nerves and its other parts in the way

required for drinking, and thus increase its malady and do itself harm, as it is natural for it, when it is not indisposed to be

stimulated to drink for its good by a similar cause; and although looking to the use for which a clock was destined by its

maker, I may say that it is de�ected from its proper nature when it incorrectly indicates the hours, and on the same

principle, considering the machine of the human body as having been formed by God for the sake of the motions which it

usually manifests, although I may likewise have ground for thinking that it does not follow the order of its nature when the

throat is parched and drink does not tend to its preservation, nevertheless I yet plainly discern that this latter acceptation

of the term nature is very different from the other: for this is nothing more than a certain denomination, depending

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entirely on my thought, and hence called extrinsic, by which I compare a sick man and an imperfectly constructed clock

with the idea I have of a man in good health and a well made clock; while by the other acceptation of nature is understood

something which is truly found in things, and therefore possessed of some truth.

18. But certainly, although in respect of a dropsical body, it is only by way of exterior denomination that we say its nature

is corrupted, when, without requiring drink, the throat is parched; yet, in respect of the composite whole, that is, of the

mind in its union with the body, it is not a pure denomination, but really an error of nature, for it to feel thirst when drink

would be hurtful to it: and, accordingly, it still remains to be considered why it is that the goodness of God does not

prevent the nature of man thus taken from being fallacious.

19. To commence this examination accordingly, I here remark, in the �rst place, that there is a vast difference between

mind and body, in respect that body, from its nature, is always divisible, and that mind is entirely indivisible. For in truth,

when I consider the mind, that is, when I consider myself in so far only as I am a thinking thing, I can distinguish in myself

no parts, but I very clearly discern that I am somewhat absolutely one and entire; and although the whole mind seems to

be united to the whole body, yet, when a foot, an arm, or any other part is cut off, I am conscious that nothing has been

taken from my mind; nor can the faculties of willing, perceiving, conceiving, etc., properly be called its parts, for it is the

same mind that is exercised [all entire] in willing, in perceiving, and in conceiving, etc. But quite the opposite holds in

corporeal or extended things; for I cannot imagine any one of them [how small soever it may be], which I cannot easily

sunder in thought, and which, therefore, I do not know to be divisible. This would be suf�cient to teach me that the mind

or soul of man is entirely different from the body, if I had not already been apprised of it on other grounds.

20. I remark, in the next place, that the mind does not immediately receive the impression from all the parts of the body,

but only from the brain, or perhaps even from one small part of it, viz, that in which the common sense (senses communis)

is said to be, which as often as it is affected in the same way gives rise to the same perception in the mind, although

meanwhile the other parts of the body may be diversely disposed, as is proved by innumerable experiments, which it is

unnecessary here to enumerate.

21. I remark, besides, that the nature of body is such that none of its parts can be moved by another part a little removed

from the other, which cannot likewise be moved in the same way by any one of the parts that lie between those two,

although the most remote part does not act at all. As, for example, in the cord A, B, C, D, [which is in tension], if its last part

D, be pulled, the �rst part A, will not be moved in a different way than it would be were one of the intermediate parts B or

C to be pulled, and the last part D meanwhile to remain �xed. And in the same way, when I feel pain in the foot, the science

of physics teaches me that this sensation is experienced by means of the nerves dispersed over the foot, which, extending

like cords from it to the brain, when they are contracted in the foot, contract at the same time the inmost parts of the

brain in which they have their origin, and excite in these parts a certain motion appointed by nature to cause in the mind a

sensation of pain, as if existing in the foot; but as these nerves must pass through the tibia, the leg, the loins, the back, and

neck, in order to reach the brain, it may happen that although their extremities in the foot are not affected, but only

certain of their parts that pass through the loins or neck, the same movements, nevertheless, are excited in the brain by

this motion as would have been caused there by a hurt received in the foot, and hence the mind will necessarily feel pain in

the foot, just as if it had been hurt; and the same is true of all the other perceptions of our senses.

22. I remark, �nally, that as each of the movements that are made in the part of the brain by which the mind is immediately

affected, impresses it with but a single sensation, the most likely supposition in the circumstances is, that this movement

causes the mind to experience, among all the sensations which it is capable of impressing upon it; that one which is the

best �tted, and generally the most useful for the preservation of the human body when it is in full health. But experience

shows us that all the perceptions which nature has given us are of such a kind as I have mentioned; and accordingly, there

Check Your Answer

Although nature teaches Descartes that there is a unity between the mind and body, he does remark that there

is a vast difference between the mind and the body.

(a) True

(b) False

The correct answer is (a) True.

To commence this examination accordingly, I here remark, in the �rst place, that there is a vast difference

between mind and body, in respect that body, from its nature, is always divisible, and that mind is entirely

indivisible

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is nothing found in them that does not manifest the power and goodness of God. Thus, for example, when the nerves of

the foot are violently or more than usually shaken, the motion passing through the medulla of the spine to the innermost

parts of the brain affords a sign to the mind on which it experiences a sensation, viz, of pain, as if it were in the foot, by

which the mind is admonished and excited to do its utmost to remove the cause of it as dangerous and hurtful to the foot.

It is true that God could have so constituted the nature of man as that the same motion in the brain would have informed

the mind of something altogether different: the motion might, for example, have been the occasion on which the mind

became conscious of itself, in so far as it is in the brain, or in so far as it is in some place intermediate between the foot and

the brain, or, �nally, the occasion on which it perceived some other object quite different, whatever that might be; but

nothing of all this would have so well contributed to the preservation of the body as that which the mind actually feels. In

the same way, when we stand in need of drink, there arises from this want a certain parchedness in the throat that moves

its nerves, and by means of them the internal parts of the brain; and this movement affects the mind with the sensation of

thirst, because there is nothing on that occasion which is more useful for us than to be made aware that we have need of

drink for the preservation of our health; and so in other instances.

23. Whence it is quite manifest that, notwithstanding the sovereign goodness of God, the nature of man, in so far as it is

composed of mind and body, cannot but be sometimes fallacious. For, if there is any cause which excites, not in the foot,

but in some one of the parts of the nerves that stretch from the foot to the brain, or even in the brain itself, the same

movement that is ordinarily created when the foot is ill affected, pain will be felt, as it were, in the foot, and the sense will

thus be naturally deceived; for as the same movement in the brain can but impress the mind with the same sensation, and

as this sensation is much more frequently excited by a cause which hurts the foot than by one acting in a different quarter,

it is reasonable that it should lead the mind to feel pain in the foot rather than in any other part of the body. And if it

sometimes happens that the parchedness of the throat does not arise, as is usual, from drink being necessary for the

health of the body, but from quite the opposite cause, as is the case with the dropsical, yet it is much better that it should

be deceitful in that instance, than if, on the contrary, it were continually fallacious when the body is well-disposed; and the

same holds true in other cases.

24. And certainly this consideration is of great service, not only in enabling me to recognize the errors to which my nature

is liable, but likewise in rendering it more easy to avoid or correct them: for, knowing that all my senses more usually

indicate to me what is true than what is false, in matters relating to the advantage of the body, and being able almost

always to make use of more than a single sense in examining the same object, and besides this, being able to use my

memory in connecting present with past knowledge, and my understanding which has already discovered all the causes of

my errors, I ought no longer to fear that falsity may be met with in what is daily presented to me by the senses. And I

ought to reject all the doubts of those bygone days, as hyperbolical and ridiculous, especially the general uncertainty

respecting sleep, which I could not distinguish from the waking state: for I now �nd a very marked difference between the

two states, in respect that our memory can never connect our dreams with each other and with the course of life, in the

way it is in the habit of doing with events that occur when we are awake. And, in truth, if some one, when I am awake,

appeared to me all of a sudden and as suddenly disappeared, as do the images I see in sleep, so that I could not observe

either whence he came or whither he went, I should not without reason esteem it either a specter or phantom formed in

my brain, rather than a real man. But when I perceive objects with regard to which I can distinctly determine both the

place whence they come, and that in which they are, and the time at which they appear to me, and when, without

interruption, I can connect the perception I have of them with the whole of the other parts of my life, I am perfectly sure

that what I thus perceive occurs while I am awake and not during sleep. And I ought not in the least degree to doubt of the

truth of these presentations, if, after having called together all my senses, my memory, and my understanding for the

purpose of examining them, no deliverance is given by any one of these faculties which is repugnant to that of any other:

for since God is no deceiver, it necessarily follows that I am not herein deceived. But because the necessities of action

frequently oblige us to come to a determination before we have had leisure for so careful an examination, it must be

confessed that the life of man is frequently obnoxious to error with respect to individual objects; and we must, in

conclusion, ac. knowledge the weakness of our nature.

Check Your Answer

Descartes argues that since we can connect the perceptions we have of objects with the whole of the other parts

of our lives, then we have a coherence between our senses, memory, and understanding. Therefore, we are not:

(a) weak

(b) in error

(c) deceived

(d) awake

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The correct answer is (c) deceived. 

But when I perceive objects with regard to which I can distinctly determine both the place whence they come,

and that in which they are, and the time at which they appear to me, and when, without interruption, I can

connect the perception I have of them with the whole of the other parts of my life, I am perfectly sure that what I

thus perceive occurs while I am awake and not during sleep. And I ought not in the least degree to doubt of the

truth of these presentations, if, after having called together all my senses, my memory, and my understanding for

the purpose of examining them, no deliverance is given by any one of these faculties which is repugnant to that

of any other: for since God is no deceiver, it necessarily follows that I am not herein deceived.

For additional information and review, feel free to complete the Unit 2 Self

Assessment - Descartes (not graded) self-assessment.