From Modern Philosophy: Essential Selections, by James Fieser


Copyright 2015, updated 1/1/2017



THE METHOD OF INVESTIGATION (from Discourse on the Method)


Aim of the Discourse (from Part 1)

It must always be recollected that possibly I deceive myself, and that what I take to be gold and diamonds is perhaps no more than copper and glass. I know how subject we are to delusion in whatever touches ourselves, and also how much the judgments of our friends ought to be suspected when they are in our favor. But in this Discourse I will be very happy to show the paths I have followed, and to set forth my life as in a picture, so that everyone may judge of it for himself; and thus in learning from the common talk what are the opinions which are held of it, a new means of obtaining self-instruction will be reached, which I will add to those which I have been in the habit of using.

            Thus my design is not here to teach the Method which everyone should follow in order to promote the good conduct of his Reason, but only to show in what manner I have endeavored to conduct my own. Those who set about giving precepts must esteem themselves more skillful than those to whom they advance them, and if they fall short in the smallest matter they must of course take the blame for it. But regarding this Treatise simply as a history, or, if you prefer it, a fable in which, among certain things which may be imitated, there are possibly others also which it would not be right to follow, I hope that it will be of use to some without being hurtful to any, and that all will thank me for my frankness.


Replacing the Old with the New: Rebuilding Cities and Rebuilding Knowledge (from Discourse, Part 2)

One of the first of the considerations that occurred to me was that there is very often less perfection in works composed of several portions, and carried out by the hands of various masters, than in those on which one individual alone has worked. Thus we see that buildings planned and carried out by one architect alone are usually more beautiful and better proportioned than those which many have tried to put in order and improve, making use of old walls which were built with other ends in view. In the same way also, those ancient cities which, originally mere villages, have become in the process of time great towns, are usually badly constructed in comparison with those which are regularly laid out on a plain by a surveyor who is free to follow his own ideas. Even though, considering their buildings each one apart, there is often as much or more display of skill in the one case than in the other, the former have large buildings and small buildings indiscriminately placed together, thus rendering the streets crooked and irregular, so that it might be said that it was chance rather than the will of men guided by reason that led to such an arrangement. If we consider that this happens despite the fact that from all time there have been certain officials who have had the special duty of looking after the buildings of private individuals in order that they may be public ornaments, we will understand how difficult it is to bring about much that is satisfactory in operating only upon the works of others. . . .

            And similarly I thought that the sciences found in books--in those at least whose reasonings are only probable and which have no demonstrations – composed as they are of the gradually accumulated opinions of many different individuals – do not approach so near to the truth as the simple reasoning which a man of common sense can quite naturally carry out respecting the things which come immediately before him. Again I thought that since we have all been children before being men, and since it has for long fallen to us to be governed by our appetites and by our teachers (who often enough contradicted each other, and none of whom perhaps counseled us always for the best), it is almost impossible that our judgments should be so excellent or solid as they should have been had we had complete use of our reason since our birth, and had we been guided by its means alone.

            It is true that we do not find that all the houses in a town are leveled to the ground for the sole reason that the town is to be rebuilt in another fashion, with streets made more beautiful; but at the same time we see that many people cause their own houses to be knocked down in order to rebuild them, and that sometimes they are forced so to do where there is danger of the houses falling of themselves, and when the foundations are not secure. From such examples I argued to myself that there was no plausibility in the claim of any private individual to reform a state by altering everything, and by overturning it throughout, in order to set it right again. Nor is it likewise probable that the whole body of the Sciences, or the order of teaching established by the Schools, should be reformed. But as regards all the opinions which up to this time I had embraced, I thought I could not do better than try once and for all to sweep them completely away, so that they might later on be replaced, either by others which were better, or by the same, when I had made them conform to the uniformity of a rational scheme. I firmly believed that by this means I should succeed in directing my life much better than if I had only built on old foundations, and relied on principles of which I allowed myself to be in youth persuaded without having inquired into their truth.


Four Rules of Logical Method (from Discourse, Part 2)

Although in reality Logic contains many precepts which are very true and very good, there are at the same time mingled with them so many others which are hurtful or superfluous. . . . As a multiplicity of laws often furnishes excuses for evil-doing, and as a State is hence much better ruled when, having but very few laws, these are most strictly observed. So, instead of the great number of precepts of which Logic is composed, I believed that I should find the four which I will state quite sufficient, provided that I adhered to a firm and constant resolve never on any single occasion to fail in their observance.

            The first of these was to accept nothing as true which I did not clearly recognize to be so; that is to say, carefully to avoid precipitation and prejudice in judgments, and to accept in them nothing more than what was presented to my mind so clearly and distinctly that I could have no occasion to doubt it.

            The second was to divide up each of the difficulties which I examined into as many parts as possible, and as seemed requisite in order that it might be resolved in the best manner possible.

            The third was to carry on my reflections in due order, commencing with objects that were the most simple and easy to understand, in order to rise little by little, or by degrees, to knowledge of the most complex, assuming an order, even if a fictitious one, among those which do not follow a natural sequence relatively to each other.

            The last was in all cases to make enumerations so complete and reviews so general that I should be certain of having omitted nothing.


Provisional Code of Morals (from Discourse, Part 3)

And finally, as it is not sufficient, before commencing to rebuild the house which we inhabit, to pull it down and provide materials and an architect (or to act in this capacity ourselves, and make a careful drawing of its design), unless we have also provided ourselves with some other house where we can be comfortably lodged during the time of rebuilding, so in order that I should not remain irresolute in my actions while reason obliged me to be so in my judgments, and that I might not omit to carry on my life as happily as I could, I formed for myself a code of morals for the time being which did not consist of more than three or four maxims, which maxims I should like to enumerate to you.

            The first was to obey the laws and customs of my country, adhering constantly to the religion in which by God’s grace I had been instructed since my childhood, and in all other things directing my conduct by opinions the most moderate in nature, and the farthest removed from excess in all those which are commonly received and acted on by the most judicious of those with whom I might come in contact. For since I began to count my own opinions as nothing, because I desired to place all under examination, I was convinced that I could not do better than follow those held by people on whose judgment reliance could be placed. . . . Among many opinions all equally received, I chose only the most moderate, both because these are always most suited for putting into practice, and probably the best (for all excess has a tendency to be bad), and also because I should have in a less degree turned aside from the right path, supposing that I was wrong, than if, having chosen an extreme course, I found that I had chosen amiss. . . .

            My second maxim was that of being as firm and resolute in my actions as I could be, and not to follow less faithfully opinions the most doubtful, when my mind was once made up regarding them, than if these had been beyond doubt. . . . From then on, this principle was sufficient to deliver me from all the penitence and remorse which usually affect the mind and agitate the conscience of those weak and vacillating creatures who allow themselves to keep changing their procedure, and practice as good, things which they afterwards judge to be evil.

            My third maxim was to try always to conquer myself rather than fortune, and to alter my desires rather than change the order of the world, and generally to accustom myself to believe that there is nothing entirely within our power but our own thoughts: so that after we have done our best in regard to the things that are without us, our ill-success cannot possibly be failure on our part. This alone seemed to me sufficient to prevent my desiring anything in the future beyond what I could actually obtain, hence rendering me content; for since our will does not naturally induce us to desire anything but what our understanding represents to it as in some way possible of attainment, it is certain that if we consider all good things which are outside of us as equally outside of our power, we should not have more regret in resigning those goods which appear to pertain to our birth, when we are deprived of them for no fault of our own, than we have in not possessing the kingdoms of China or Mexico. ...

            And last of all, to conclude this moral code, I felt it necessary to make a review of the various occupations of men in this life in order to try to choose out the best. Without wishing to say anything of the employment of others, I thought that I could not do better than continue in the one in which I found myself engaged. That is to say, I occupy my whole life in cultivating my Reason, and in advancing myself as much as possible in the knowledge of the truth in accordance with the method which I had prescribed myself. I had experienced so much satisfaction since beginning to use this method, that I did not believe that any sweeter or more innocent could in this life be found, every day discovering by its means some truths which seemed to me sufficiently important, although commonly ignored by other men.




Need to Doubt only the Foundations of Knowledge through the Senses

It is now some years since I detected how many were the false beliefs that I had from my earliest youth admitted as true, and how doubtful was everything I had since constructed on this basis. From that time I was convinced that I must once and for all seriously undertake to rid myself of all the opinions which I had formerly accepted, and begin to build anew from the foundation, if I wanted to establish any firm and permanent structure in the sciences. But as this enterprise appeared to be a very great one, I waited until I had attained an age so mature that I could not hope that at any later date I should be better fitted to execute my design. This reason caused me to delay so long that I should feel that I was doing wrong were I to occupy in deliberation the time that yet remains to me for action. Today, then, since very opportunely for the plan I have in view I have delivered my mind from every care [and am happily agitated by no passions] and since I have procured for myself an assured leisure in a peaceable retirement, I will at last seriously and freely address myself to the general upheaval of all my former opinions.

            Now for this object it is not necessary that I should show that all of these are false; I will perhaps never arrive at this end. But reason already persuades me that I ought no less carefully to withhold my assent from matters which are not entirely certain and indubitable than from those which appear to me evidently to be false. Consequently, if I am able to find in each one some reason to doubt, this will suffice to justify my rejecting the whole. For that end it will not be necessary for me to examine each one in particular, which would be an endless task. But because the destruction of the foundations necessarily brings with it the downfall of the rest of the edifice, I will only in the first place attack those principles upon which all my former opinions rested.

            All that up to the present time I have accepted as most true and certain I have learned either from the senses or through the senses; but it is sometimes proved to me that these senses are deceptive, and it is wiser not to trust entirely to anything by which we have once been deceived.


Doubting Hypothesis 1: My Senses are Unreliable (e.g., Optical Illusions)

It may be that the senses sometimes deceive us concerning things which are hardly perceptible, or very far away. However, there are yet many others to be met with as to which we cannot reasonably have any doubt, although we recognize them by their means. For example, there is the fact that I am here, seated by the fire, wearing a dressing gown, having this paper in my hands and other similar matters. How could I deny that these hands and this body are mine? Perhaps only comparing myself to certain people who lack sense, whose cerebella are so troubled and clouded by the violent vapors of black bile, that they constantly assure us that they think they are kings when they are really quite poor, or that they are clothed in purple when they are really without covering, or who imagine that they have a head made of pottery, or are nothing but pumpkins, or are made of glass. But they are mad, and I should not be any the less insane were I to follow examples so extravagant.


Doubting Hypothesis 2: Maybe I am Dreaming

At the same time I must remember that I am a man, and that consequently I am in the habit of sleeping, and in my dreams I represent to myself the same things or sometimes even less probable things, than do those who are insane in their waking moments. How often has it happened to me that in the night I dreamt that I found myself in this particular place, that I was dressed and seated near the fire, while in reality I was lying undressed in bed! At this moment it does indeed seem to me that it is with eyes awake that I am looking at this paper; that this head which I move is not asleep, that it is deliberately and of set purpose that I extend my hand and perceive it; what happens in sleep does not appear so clear nor so distinct as does all this. But in thinking over this I remind myself that on many occasions I have in sleep been deceived by similar illusions, and in dwelling carefully on this reflection I see so evidently that there are no certain indications by which we may clearly distinguish wakefulness from sleep that I am lost in astonishment. My astonishment is such that it is almost capable of persuading me that I now dream.

            Now let us assume that we are asleep and that all these particulars, for example, that we open our eyes, shake our head, extend our hands, and so on, are but false delusions. Let us also reflect that possibly neither our hands nor our whole body are such as they appear to us to be. At the same time we must at least confess that the things which are represented to us in sleep are like painted representations which can only have been formed as the counterparts of something real and true. In this way, those general things at least (that is, eyes, a head, hands, and a whole body) are not imaginary things, but things really existent. For, as a matter of fact, painters, even when they study with the greatest skill to represent sirens and satyrs by forms the most strange and extraordinary, cannot give them natures which are entirely new, but merely make a certain medley of the members of different animals. Or if their imagination is extravagant enough to invent something so novel that nothing similar has ever before been seen, and that then their work represents a thing purely fictitious and absolutely false, it is certain all the same that the colors of which this is composed are necessarily real. For the same reason, although these general things—that is, [a body], eyes, a head, hands, and such like—may be imaginary, we are bound at the same time to confess that there are at least some other objects yet more simple and more universal, which are real and true. Of these, just in the same way as with certain real colors, all these images of things which dwell in our thoughts, whether true and real or false and fantastic, are formed.

            To such a class of things pertains corporeal nature in general, and its extension, the figure of extended things, their quantity or magnitude and number, as also the place in which they are, the time which measures their duration, and so on.

            That is possibly why our reasoning is not unjust when we conclude from this that Physics, Astronomy, Medicine and all other sciences which have as their end the consideration of composite things, are very dubious and uncertain; but that Arithmetic, Geometry and other sciences of that kind which only treat of things that are very simple and very general, without taking great trouble to determine whether they are actually existent or not, contain some measure of certainty and an element of the indubitable. For whether I am awake or asleep, two and three together always form five, and the square can never have more than four sides, and it does not seem possible that truths so clear and apparent can be suspected of any falsity [or uncertainty].


Doubting Hypothesis 3: Maybe an Evil Genius Deceives me

Nevertheless I have long had fixed in my mind the belief that an all-powerful God existed by whom I have been created such as I am. But how do I know that he has not brought it to pass that there is no earth, no heaven, no extended body, no magnitude, no place, and that nevertheless [I possess the perceptions of all these things and that] they seem to me to exist just exactly as I now see them? And, besides, as I sometimes imagine that others deceive themselves in the things which they think they know best, how do I know that I am not deceived every time that I add two and three, or count the sides of a square, or judge of things yet simpler, if anything simpler can be imagined? But possibly God has not desired that I should be thus deceived, for he is said to be supremely good. If, however, it is contrary to his goodness to have made me such that I constantly deceive myself, it would also appear to be contrary to his goodness to permit me to be sometimes deceived, and nevertheless I cannot doubt that he does permit this. . . .

            I will then suppose, not that God who is supremely good and the fountain of truth, but some evil genius not less powerful than deceitful, has employed his whole energies in deceiving me. I will consider that the heavens, the earth, colors, figures, sound, and all other external things are nothing but the illusions and dreams of which this genius has availed himself in order to lay traps for my gullibility. I will consider myself as having no hands, no eyes, no flesh, no blood, nor any senses, yet falsely believing myself to possess all these things. I will remain obstinately attached to this idea, and if by this means it is not in my power to arrive at the knowledge of any truth, I may at least do what is in my power [that is, suspend my judgment], and with firm purpose avoid giving credence to any false thing, or being imposed upon by this arch deceiver, however powerful and deceptive he may be. But this task is a laborious one, and insensibly a certain lethargy leads me into the course of my ordinary life. Just as a captive who in sleep enjoys an imaginary liberty, when he begins to suspect that his liberty is but a dream, fears to awaken, and conspires with these agreeable illusions that the deception may be prolonged, so insensibly of my own accord I fall back into my former opinions, and I dread awakening from this slumber, lest the laborious wakefulness which would follow the tranquility of this calmness should have to be spent not in daylight, but in the excessive darkness of the difficulties which have just been discussed.




Review: Extent of Doubt so Far

The Meditation of yesterday filled my mind with so many doubts that it is no longer in my power to forget them, yet I do not see in what manner I can resolve them. Just as if I had all of a sudden fallen into very deep water, I am so baffled that I can neither make certain of setting my feet on the bottom, nor can I swim and so support myself on the surface. I will nevertheless make an effort and follow anew the same path as that on which I yesterday entered, that is, I will proceed by setting aside all that in which the least doubt could be supposed to exist, just as if I had discovered that it was absolutely false. I will ever follow in this road until I have met with something which is certain, or at least, if I can do nothing else, until I have learned for certain that there is nothing in the world that is certain. Archimedes, in order that he might draw the terrestrial globe out of its place, and transport it elsewhere, demanded only that one point should be fixed and immovable. In the same way I will have the right to conceive high hopes if I am happy enough to discover one thing only which is certain and indubitable.

            I suppose, then, that all the things that I see are false; I persuade myself that nothing has ever existed of all that my fallacious memory represents to me. I consider that I possess no senses; I imagine that body, figure, extension, movement and place are but the fictions of my mind. What, then, can be distinguished as true? Perhaps nothing at all, unless that there is nothing in the world that is certain.


I Still Know that I Exist (I Think, Therefore I am)

But how can I know there is not something different from those things that I have just considered, of which one cannot have the slightest doubt? Is there not some God, or some other being by whatever name we call it, who puts these reflections into my mind? That is not necessary, for is it not possible that I am capable of producing them myself? I myself, am I not at least something? But I have already denied that I had senses and body. Yet I hesitate, for what follows from that? Am I so dependent on body and senses that I cannot exist without these? But I was persuaded that there was nothing in all the world, that there was no heaven, no earth, that there were no minds, nor any bodies: was I not then likewise persuaded that I did not exist? Not at all; of a surety I myself did exist since I persuaded myself of something [or merely because I thought of something]. But there is some deceiver or other, very powerful and very cunning, who ever employs his ingenuity in deceiving me. Then without doubt I exist also if he deceives me, and let him deceive me as much as he will, he can never cause me to be nothing so long as I think that I am something. So that after having reflected well and carefully examined all things, we must come to the definite conclusion that this proposition: I am, I exist, is necessarily true each time that I pronounce it, or that I mentally conceive it.


Perhaps my Identity consists of being a Rational Animal

But I do not yet know clearly enough what I am, I who am certain that I am. Hence I must be careful to see that I do not imprudently take some other object in place of myself, and thus that I do not go astray in respect of this knowledge that I hold to be the most certain and most evident of all that I have formerly learned. That is why I will now consider anew what I believed myself to be before I started upon these last reflections. Of my former opinions I will withdraw all that might even in a small degree be invalidated by the reasons which I have just brought forward, in order that there may be nothing at all left beyond what is absolutely certain and indubitable.

            What then did I formerly believe myself to be? Undoubtedly I believed myself to be a human. But what is a human? Should I say a rational animal? Certainly not. For then I should have to inquire what an animal is, and what is rational. Thus from a single question I should insensibly fall into an infinitude of others more difficult; and I should not wish to waste the little time and leisure remaining to me in trying to unravel subtleties like these.


Perhaps my Identity consists of being Body and Soul

But I will rather stop here to consider the thoughts which of themselves spring up in my mind, and which were not inspired by anything beyond my own nature alone when I applied myself to the consideration of my being. In the first place, then, I considered myself as having a face, hands, arms, and all that system of members composed on bones and flesh as seen in a corpse which I designated by the name of body. In addition to this I considered that I was nourished, that I walked, that I felt, and that I thought, and I referred all these actions to the soul. But I did not stop to consider what the soul was, or if I did stop, I imagined that it was something extremely rare and subtle like a wind, a flame, or an ether, which was spread throughout my grosser parts. As to body I had no manner of doubt about its nature, but thought I had a very clear knowledge of it. If I had desired to explain it according to the notions that I had then formed of it, I should have described it as follows. By the body I understand all that which can be defined by a certain figure. It is something which can be confined in a certain place, and which can fill a given space in such a way that every other body will be excluded from it. It can be perceived either by touch, or by sight, or by hearing, or by taste, or by smell. It can be moved in many ways, not, in truth, by itself, but by something which is foreign to it, by which it is touched [and from which it receives impressions]. For to have the power of self-movement, as also of feeling or of thinking, I did not consider to belonged to the nature of body. On the contrary, I was rather astonished to find that faculties similar to them existed in some bodies.

            But what am I, now that I suppose that there is a certain genius which is extremely powerful, and, if I may say so, malicious, who employs all his powers in deceiving me? Can I affirm that I possess the least of all those things which I have just said pertain to the nature of body? I pause to consider, I revolve all these things in my mind, and I find none of which I can say that it pertains to me. It would be tedious to stop to enumerate them.

            Let us pass to the attributes of soul and see if there is any one which is in me. What of nutrition or walking [the first mentioned]? But if it is so that I have no body it is also true that I can neither walk nor take nourishment. Another attribute is sensation. But one cannot feel without body, and besides I have thought I perceived many things during sleep that I recognized in my waking moments as not having been experienced at all. What of thinking? I find here that thought is an attribute that belongs to me; it alone cannot be separated from me. I am, I exist, that is certain. But how often? Just when I think; for it might possibly be the case if I ceased entirely to think, that I should likewise cease altogether to exist. I do not now admit anything which is not necessarily true. To speak accurately I am not more than a thing which thinks, that is to say a mind or a soul, or an understanding, or a reason, which are terms whose significance was formerly unknown to me. I am, however, a real thing and really exist; but what thing? I have answered: a thing which thinks.


My Identity cannot Consist of what I merely Imagine about Myself

And what more? I will exercise my imagination [in order to see if I am not something more]. I am not a collection of members which we call the human body: I am not a subtle air distributed through these members, I am not a wind, a fire, a vapor, a breath, nor anything at all which I can imagine or conceive; because I have assumed that all these were nothing. Without changing that supposition I find that I only leave myself certain of the fact that I am somewhat. But perhaps it is true that these same things which I supposed were non-existent because they are unknown to me, are really not different from the self which I know. I am not sure about this, I will not dispute about it now. I can only give judgment on things that are known to me.

            I know that I exist, and I inquire what I am, I whom I know to exist. But it is very certain that the knowledge of my existence taken in its precise significance does not depend on things whose existence is not yet known to me. Consequently it does not depend on those which I can pretend in imagination. . . .


Me as a Thinking Thing

But what then am I? A thing which thinks. What is a thing which thinks? It is a thing which doubts, understands, [conceives], affirms, denies, wills, refuses, which also imagines and feels.

            Certainly it is no small matter if all these things pertain to my nature. But why should they not so pertain? Am I not that being who now doubts nearly everything, who nevertheless understands certain things, who affirms that one only is true, who denies all the others, who desires to know more, is averse from being deceived, who imagines many things, sometimes indeed despite his will, and who perceives many likewise, as by the intervention of the bodily organs? Is there nothing in all this which is as true as it is certain that I exist, even though I should always sleep and though he who has given me being employed all his ingenuity in deceiving me? Is there likewise any one of these attributes which can be distinguished from my thought, or which might be said to be separated from myself? For it is so evident of itself that it is I who doubts, who understands, and who desires, that there is no reason here to add anything to explain it. I have certainly the power of imagining likewise; for although it may happen (as I formerly supposed) that none of the things which I imagine are true, nevertheless this power of imagining does not cease to be really in use, and it forms part of my thought. Finally, I am the same who feels, that is to say, who perceives certain things, as by the organs of sense, since in truth I see light, I hear noise, I feel heat. But it will be said that these phenomena are false and that I am dreaming. Let it be so; still it is at least quite certain that it seems to me that I see light, that I hear noise and that I feel heat. That cannot be false; properly speaking it is what is in me called feeling; and used in this precise sense that is no other thing than thinking.




Maybe Physical Objects are more Clearly Known to me than is my Self

From this time I begin to know what I am with a little more clearness and distinction than before. But nevertheless it still seems to me, and I cannot prevent myself from thinking, that corporeal things, whose images are framed by thought, which are tested by the senses, are much more distinctly known than that obscure part of me which does not come under the imagination. Although really it is very strange to say that I know and understand more distinctly these things whose existence seems to me dubious, which are unknown to me, and which do not belong to me, than others of the truth of which I am convinced, which are known to me and which pertain to my real nature, in a word, than myself. But I see clearly how the case stands: my mind loves to wander, and cannot yet tolerate itself to be retained within the just limits of truth. Very good, let us once more give it the freest rein, so that, when afterwards we seize the proper occasion for pulling up, it may the more easily be regulated and controlled.


Example: Differing Attributes of Wax when Solid vs. Liquid

Let us begin by considering the most common matters, those which we believe to be the most distinctly comprehended, namely, the bodies which we touch and see; not indeed bodies in general, for these general ideas are usually a little more confused, but let us consider one body in particular. Let us take, for example, this piece of wax: it has been taken quite freshly from the hive, and it has not yet lost the sweetness of the honey which it contains; it still retains somewhat of the odor of the flowers from which it has been culled; its color, its figure, its size are apparent; it is hard, cold, easily handled, and if you strike it with the finger, it will emit a sound. Finally all the things which are required to cause us distinctly to recognize a body, are met with in it. But notice that while I speak and approach the fire what remained of the taste is exhaled, the smell evaporates, the color alters, the figure is destroyed, the size increases, it becomes liquid, it heats, scarcely can one handle it, and when one strikes it, now sound is emitted. Does the same wax remain after this change? We must confess that it remains; none would judge otherwise.


Sameness of Wax not Determined by the Senses or Imagination

What then did I know so distinctly in this piece of wax? It could certainly be nothing of all that the senses brought to my notice, since all these things which fall under taste, smell, sight, touch, and hearing, are found to be changed, and yet the same wax remains.

            Perhaps it was what I now think, namely, that this wax was not that sweetness of honey, nor that agreeable scent of flowers, nor that particular whiteness, nor that figure, nor that sound, but simply a body which a little while before appeared to me as perceptible under these forms, and which is now perceptible under others. But what, precisely, is it that I imagine when I form such conceptions? Let us attentively consider this, and, abstracting from all that does not belong to the wax, let us see what remains. Certainly nothing remains except a certain extended thing which is flexible and movable. But what is the meaning of flexible and movable? Is it not that I imagine that this piece of wax being round is capable of becoming square and of passing from a square to a triangular figure? No, certainly it is not that, since I imagine it admits of an infinitude of similar changes, and I nevertheless do not know how to compass the infinitude by my imagination, and consequently this conception which I have of the wax is not brought about by the faculty of imagination. What now is this extension? Is it not also unknown? For it becomes greater when the wax is melted, greater when it is boiled, and greater still when the heat increases; and I should not conceive [clearly] according to truth what wax is, if I did not think that even this piece that we are considering is capable of receiving more variations in extension than I have ever imagined.


Sameness of Wax Determined by the Mind Alone

We must then grant that I could not even understand through the imagination what this piece of wax is, and that it is my mind alone which perceives it. I say this piece of wax in particular, for as to wax in general it is yet clearer. But what is this piece of wax which cannot be understood except by the [understanding or] mind? It is certainly the same that I see, touch, imagine, and finally it is the same which I have always believed it to be from the beginning. But what must particularly be observed is that its perception is neither an act of vision, nor of touch, nor of imagination, and has never been such although it may have appeared formerly to be so. Its perception is only an intuition of the mind, which may be imperfect and confused as it was formerly, or clear and distinct as it is at present, according as my attention is more or less directed to the elements which are found in it, and of which it is composed. . . .

            But finally here I am, having insensibly reverted to the point I desired. It is now evident to me that even bodies are not properly speaking known by the senses or by the faculty of imagination, but by the understanding only. They are not known from the fact that they are seen or touched, but only because they are understood. Thus, I see clearly that there is nothing which is easier for me to know than my mind. But because it is difficult to rid oneself so promptly of an opinion to which one was accustomed for so long, it will be well that I should halt a little at this point, so that by the length of my meditation I may more deeply imprint on my memory this new knowledge.




Summary to Date

I will now close my eyes, I will stop my ears, I will call away all my senses, I will obliterate even from my thoughts all the images of corporeal things, or at least (for that is hardly possible) I will consider them as vain and false. Thus holding converse only with myself and considering my own nature, I will try little by little to reach a better knowledge of and a more familiar acquaintanceship with myself. I am a thing that thinks, that is to say, that doubts, affirms, denies, that knows a few things, that is ignorant of many [that loves, that hates], that wills, that desires, that also imagines and perceives; for as I remarked before, although the things which I perceive and imagine are perhaps nothing at all apart from me and in themselves, I am nevertheless assured that these modes of thought that I call perceptions and imaginations, inasmuch only as they are modes of thought, certainly reside [and are met with] in me.


“I Exist” Perceived Clearly and Distinctly

And in the little that I have just said, I think I have summed up all that I really know, or at least all that until now I was aware that I knew. In order to try to extend my knowledge further, I will now look around more carefully and see whether I cannot still discover in myself some other things which I have not until now perceived. I am certain that I am a thing which thinks. But do I not then likewise know what is required to render me certain of a truth? Certainly in this first knowledge there is nothing that assures me of its truth, except the clear and distinct perception of that which I state, which would not indeed suffice to assure me that what I say is true, if it could ever happen that a thing which I conceived so clearly and distinctly could be false. Accordingly it seems to me that already I can establish as a general rule that all things which I perceive very clearly and very distinctly are true.


Reliability of Clarity and Distinctness rests on God not being a Deceiver

At the same time I have before received and admitted many things to be very certain and evident, which yet I afterwards recognized as being dubious. What then were these things? They were the earth, sky, stars and all other objects which I grasped by means of the senses. But what did I clearly [and distinctly] perceive in them? Nothing more than that the ideas or thoughts of these things were presented to my mind. Not even now do I deny that these ideas are met with in me. But there was yet another thing which I affirmed, and which, owing to the habit which I had formed of believing it, I thought I perceived very clearly, although in truth I did not perceive it at all, namely, that there were objects outside of me from which these ideas proceeded, and to which they were entirely similar. It was in this that I erred, or, if perchance my judgment was correct, this was not due to any knowledge arising from my perception.

            But when I took anything very simple and easy in the sphere of arithmetic or geometry into consideration, for example, that two and three together made five, and other things of the sort, were not these present to my mind so clearly as to enable me to affirm that they were true? Certainly if I judged that since such matters could be doubted, this would not have been so for any other reason than that it came into my mind that perhaps a God might have endowed me with such a nature that I may have been deceived even concerning things which seemed to me most evident. But every time that this preconceived opinion of the sovereign power of a God presents itself to my thought, I am constrained to confess that it is easy to Him, if he wishes it, to cause me to err, even in matters in which I believe myself to have the best evidence. On the other hand, always when I direct my attention to things which I believe myself to perceive very clearly, I am so persuaded of their truth that I let myself break out into words such as these: Let who will deceive me, he can never cause me to be nothing while I think that I am, or some day cause it to be true to say that I have never been, it being true now to say that I am, or that two and three make more or less than five, or any such thing in which I see a evident contradiction.

            And, certainly, since I have no reason to believe that there is a God who is a deceiver, and as I have not yet satisfied myself that there is a God at all, the reason for doubt which depends on this opinion alone is very slight, and so to speak metaphysical. But in order to be able altogether to remove it, I must inquire whether there is a God as soon as the occasion presents itself. If I find that there is a God, I must also inquire whether he may be a deceiver. For without a knowledge of these two truths I do not see that I can ever be certain of anything.



Causal Principle: More Perfect Ideas cannot be caused by Less Perfect Ideas

Now it is evident by the natural light that there must at least be as much reality in the efficient and total cause as in its effect. For, I ask, from where can the effect derive its reality, if not from its cause? And in what way can this cause communicate this reality to it, unless it possessed it in itself? And from this it follows, not only that something cannot proceed from nothing, but likewise that what is more perfect that is to say, which has more reality within itself cannot proceed from the less perfect. This is not only evidently true of those effects which possess actual or formal reality, but also of the ideas in which we consider merely what is termed objective reality. To take an example, the stone which has not yet existed not only cannot now begin to be unless it has been produced by something which possesses within itself, either formally or eminently, all that enters into the composition of the stone [that is, it must possess the same things or other more excellent things than those which exist in the stone]. Heat can only be produced in a subject in which it did not previously exist by a cause that is of an order [degree or kind] at least as perfect as heat, and so in all other cases.

            But further, the idea of heat, or of a stone, cannot exist in me unless it has been placed within me by some cause which possesses within it at least as much reality as that which I conceive to exist in the heat or the stone. For although this cause does not transmit anything of its actual or formal reality to my idea, we must not for that reason imagine that it is necessarily a less real cause; we must remember that [since every idea is a work of the mind] its nature is such that it demands of itself no other formal reality than that which it borrows from my thought, of which it is only a mode [that is, a manner or way of thinking]. But in order that an idea should contain some one certain objective reality rather than another, it must without doubt derive it from some cause in which there is at least as much formal reality as this idea contains of objective reality. For if we imagine that something is found in an idea which is not found in the cause, it must then have been derived from nothing; but however imperfect may be this mode of being by which a thing is objectively [or by representation] in the understanding by its idea, we cannot certainly say that this mode of being is nothing, nor consequently, that the idea derives its origin from nothing. . . .


I can be the Source of Less Perfect Ideas of Objects, Animals, People

And the longer and the more carefully that I investigate these matters, the more clearly and distinctly do I recognize their truth. But what am I to conclude from it all in the end? It is this, that if the objective reality of any one of my ideas is of such a nature as clearly to make me recognize that it is not in me either formally or eminently, and that consequently I cannot myself be the cause of it, it follows of necessity that I am not alone in the world, but that there is another being which exists, or which is the cause of this idea. On the other hand, had no such an idea existed in me, I should have had no sufficient argument to convince me of the existence of any being beyond myself; for I have made very careful investigation everywhere and up to the present time have been able to find no other ground.

            But of my ideas, beyond that which represents me to myself, as to which there can here be no difficulty, there is another which represents a God, and there are others representing corporeal and inanimate things, others angels, others animals, and others again which represent to me men similar to myself.

            As regards the ideas which represent to me other men or animals, or angels, I can however easily conceive that they might be formed by an admixture of the other ideas which I have of myself, of corporeal things, and of God, even although there were apart from me neither men nor animals, nor angels, in all the world. . . .


Proof of God: Idea of Infinite Perfection Arises from Outside of Me from God

Hence there remains only the idea of God, concerning which we must consider whether it is something which cannot have proceeded from me myself. By the name God I understand a substance that is infinite [eternal, immutable], independent, all-knowing, all-powerful, and by which I myself and everything else, if anything else does exist, have been created. Now all these characteristics are such that the more diligently I attend to them, the less do they appear capable of proceeding from me alone; hence, from what has been already said, we must conclude that God necessarily exists.

            For although the idea of substance is within me owing to the fact that I am substance, nevertheless I should not have the idea of an infinite substance since I am finite if it had not proceeded from some substance which was truly infinite.


Possible Criticism: Perhaps the Finite is a Negation of the Infinite

Nor should I imagine that I do not perceive the infinite by a true idea, but only by the negation of the finite, just as I perceive calmness and darkness by the negation of movement and of light; for, on the contrary, I see that there is evidently more reality in infinite substance than in finite, and therefore that in some way I have in me the notion of the infinite earlier then the finite namely, the notion of God before that of myself. For how would it be possible that I should know that I doubt and desire, that is to say, that something is lacking to me, and that I am not quite perfect, unless I had within me some idea of a Being more perfect than myself, in comparison with which I should recognize the deficiencies of my nature? . . .


Possible Criticism: Perhaps I am Potentially Infinitely Perfect

But possibly I am something more than I suppose myself to be, and perhaps all those perfections which I attribute to God are in some way potentially in me, although they do not yet reveal themselves, or issue in action. As a matter of fact I am already sensible that my knowledge increases [and perfects itself] little by little, and I see nothing which can prevent it from increasing more and more into infinitude; nor do I see, after it has thus been increased [or perfected], anything to prevent my being able to acquire by its means all the other perfections of the Divine nature; nor finally why the power I have of acquiring these perfections, if it really exists in me, will not suffice to produce the ideas of them.

            At the same time I recognize that this cannot be. It is true that every day my knowledge acquired new degrees of perfection, and that there were in my nature many things potentially which are not yet there actually. Nevertheless these excellences do not pertain to [or make the smallest approach to] the idea which I have of God in whom there is nothing merely potential [but in whom all is present really and actually]. For it is an infallible token of imperfection in my knowledge that it increases little by little. Further, although my knowledge grows more and more, nevertheless I do not for that reason believe that it can ever be actually infinite, since it can never reach a point so high that it will be unable to attain to any greater increase. But I understand God to be actually infinite, so that he can add nothing to his supreme perfection. Finally I perceive that the objective being of an idea cannot be produced by a being that exists potentially only, which properly speaking is nothing, but only by a being which is formal or actual.


God is Not a Deceiver

And one certainly ought not to find it strange that God, in creating me, placed this idea within me to be like the mark of the workman imprinted on his work; and it is likewise not essential that the mark will be something different from the work itself. For from the sole fact that God created me it is most probable that in some way he has placed his image and likeness upon me, and that I perceive this likeness (in which the idea of God is contained) by means of the same faculty by which I perceive myself. That is to say, when I reflect on myself I not only know that I am something [imperfect], incomplete and dependent on another, which incessantly aspires after something which is better and greater than myself, but I also know that he on whom I depend possesses in Himself all the great things towards which I aspire [and the ideas of which I find within myself]. He possesses this not indefinitely or potentially alone, but really, actually and infinitely; and that thus he is God. The whole strength of the argument which I have here made use of to prove the existence of God consists in this, that I recognize that it is not possible that my nature should be what it is, and indeed that I should have in myself the idea of a God, if God did not truly exist. Such a God, I say, whose idea is in me, that is, who possesses all those supreme perfections of which our mind may indeed have some idea (but without understanding them all), who is liable to no errors or defect [and who has none of all those marks which denote imperfection]. From this it is evident that he cannot be a deceiver, since the light of nature teaches us that fraud and deception necessarily proceed from some defect.




The Understanding is Sufficient and not the Source of Error

In the next place I experienced in myself a certain capacity for judging which I have doubtless received from God, like all the other things that I possess; and as he could not desire to deceive me, it is clear that he has not given me a faculty that will lead me to err if I use it correctly. . . .

            Whereupon, regarding myself more closely, and considering what are my errors (for they alone testify to there being any imperfection in me), I answer that they depend on a combination of two causes, namely, on the faculty of knowledge that rests in me, and on the power of choice or of free will -- that is to say, of the understanding and at the same time of the will.

            For by the understanding alone I [neither assert nor deny anything, but] mean the ideas of things as to which I can form a judgment. But no error is properly speaking found in it, provided the word error is taken in its proper meaning. Though there is possibly an infinitude of things in the world of which I have no idea in my understanding, we cannot for all that say that it is deprived of these ideas [as we might say of something which is required by its nature], but simply it does not possess these. For in truth there is no reason to prove that God should have given me a greater faculty of knowledge than he has given me. However skillful a workman I represent him to be, I should not for all that consider that he was bound to have placed in each of his works all the perfections which he may have been able to place in some.


The Will is Limitless and not the Source of Error

No doubt respecting this matter could remain if it were not that the consequence would seem to follow that I can thus never be deceived. For if I hold all that I possess from God, and if he has not placed in me the capacity for error, it seems as though I could never fall into error. It is true that when I think only of God [and direct my mind wholly to Him], I discover [in myself] no cause of error, or falsity; yet directly afterwards, when recurring to myself, experience shows me that I am nevertheless subject to an infinitude of errors. . . .

            I likewise cannot complain that God has not given me a free choice or a will which is sufficient, ample and perfect, since as a matter of fact I am conscious of a will so extended as to be subject to no limits. What seems to me very remarkable in this regard is that of all the qualities which I possess there is no one so perfect and so comprehensive that I do not very clearly recognize that it might be yet greater and more perfect. For, to take an example, if I consider the faculty of comprehension which I possess, I find that it is of very small extent and extremely limited, and at the same time I find the idea of another faculty much more ample and even infinite, and seeing that I can form the idea of it, I recognize from this very fact that it pertains to the nature of God. If in the same way I examine the memory, the imagination, or some other faculty, I do not find any which is not small and circumscribed, while in God it is immense [or infinite]. It is free-will alone or liberty of choice which I find to be so great in me that I can conceive no other idea to be greater. It is indeed the case that it is for the most part this will that causes me to know that in some manner I bear the image and likeness of God. For although the power of will is incomparably greater in God than in me, both by reason of the knowledge and the power which, conjoined with it, render it stronger and more effective, and by reason of its object, inasmuch as in God it extends to a great many things; it nevertheless does not seem to me greater if I consider it formally and precisely in itself. For the faculty of will consists alone in our having the power of choosing to do a thing or choosing not to do it (that is, to affirm or deny, to pursue or to shun it), or rather it consists alone in the fact that in order to affirm or deny, pursue or shun those things placed before us by the understanding, we act so that we are unconscious that any outside force constrains us in doing so.


Error Arises from Extending the Will Beyond our Knowledge

From all this I recognize that the power of will which I have received from God is not of itself the source of my errors -- for it is very ample and very perfect of its kind -- any more than is the power of understanding. For since I understand nothing but by the power which God has given me for understanding, there is no doubt that all that I understand, I understand as I ought, and it is not possible that I err in this. From where, then, come my errors? They come from the sole fact that since the will is much wider in its range and compass than the understanding, I do not restrain it within the same bounds, but extend it also to things which I do not understand. As the will is of itself indifferent to these, it easily falls into error and sin, and chooses the evil for the good, or the false for the true. . . .

            If I abstain from giving my judgment on anything when I do not perceive it with sufficient clearness and distinctness, it is plain that I act rightly and am not deceived. But if I determine to deny or affirm, I no longer make use as I should of my free will. If I affirm what is not true, it is evident that I deceive myself; even though I judge according to truth, this comes about only by chance, and I do not escape the blame of misusing my freedom. For the light of nature teaches us that the knowledge of the understanding should always precede the determination of the will. It is in the misuse of the free will that the privation which constitutes the characteristic nature of error is met with. Privation, I say, is found in the act, in so far as it proceeds from me, but it is not found in the faculty which I have received from God, nor even in the act in so far as it depends on him. . . .


Cannot Blame God for giving us Limited Knowledge or a Boundless Will

I have certainly no cause to complain that God has not given me an intelligence which is more powerful, or a natural light which is stronger than that which I have received from him. For, it is proper to the finite understanding not to comprehend a multitude of things, and it is proper to a created understanding to be finite. On the contrary, I have every reason to give thanks to God who owes me nothing and who has given me all the perfections I possess, and I should be far from charging him with injustice, and with having deprived me of, or wrongfully withheld from me, these perfections which he has not bestowed upon me.

            I have further no reason to complain that he has given me a will more ample than my understanding, for since the will consists only of one single element, and is so to speak indivisible, it appears that its nature is such that nothing can be abstracted from it [without destroying it]. Certainly the more comprehensive it is found to be, the more reason I have to express gratitude to the giver. . . .


Clarity and Distinctness is a Reliable Indicator of Truth

Inasmuch as it is in this that the greatest and principal perfection of man consists, it seems to me that I have gained much by this day’s Meditation, since I have discovered the source of falsity and error. Certainly there can be no other source than that which I have explained. For as often as I so restrain my will within the limits of my knowledge that it forms no judgment except on matters which are clearly and distinctly represented to it by the understanding, I can never be deceived. For every clear and distinct conception is without doubt something, and hence cannot derive its origin from what is nothing, but must of necessity have God as its author -- God, I say, who being supremely perfect, cannot be the cause of any error; and consequently we must conclude that such a conception [or such a judgment] is true. Nor have I only learned today what I should avoid in order that I may not err, but also how I should act in order to arrive at a knowledge of the truth; for without doubt I will arrive at this end if I devote my attention sufficiently to those things which I perfectly understand; and if I separate from these that which I only understand confusedly and with obscurity. To these I will henceforth diligently give heed.




Continued Confidence in Long Proofs when each Step is Clear and Distinct

I am of such a nature that as long as I understand anything very clearly and distinctly, I am naturally impelled to believe it to be true. However, I am also of such a nature that I cannot have my mind constantly fixed on the same object in order to perceive it clearly. As I often recollect having formed a past judgment without at the same time properly recollecting the reasons that led me to make it, it may happen at the moment that other reasons present themselves to me, which would easily cause me to change my opinion. In these cases if I were ignorant of the facts of the existence of God, I should have no true and certain knowledge, but only vague and vacillating opinions. Thus, for example, when I consider the nature of a [rectilinear] triangle, I who have some little knowledge of the principles of geometry recognize quite clearly that the three angles are equal to two right angles. It is not possible for me not to believe this so long as I apply my mind to its demonstration. But as soon as I abstain from attending to the proof, although I still recollect having clearly comprehended it, it may easily occur that I come to doubt its truth, if I am ignorant of there being a God. For I can persuade myself of having been so constituted by nature that I can easily deceive myself even in those matters which I believe myself to grasp with the greatest evidence and certainty, especially when I recollect that I have frequently judged matters to be true and certain which other reasons have afterwards impelled me to judge to be altogether false.

            I have recognized that all things depend upon God, and that he is not a deceiver, and from that have inferred that what I perceive clearly and distinctly cannot fail to be true. But after I have recognized that there is a God, although I no longer pay attention to the reasons for which I have judged this to be true, provided that I recollect having clearly and distinctly perceived it no contrary reason can be brought forward which could ever cause me to doubt of its truth. Thus I have a true and certain knowledge of it. This same knowledge extends likewise to all other things which I recollect having formerly demonstrated, such as the truths of geometry and the like. For what can be alleged against them to cause me to place them in doubt? Will it be said that my nature is such as to cause me to be frequently deceived? But I already know that I cannot be deceived in the judgment whose grounds I know clearly. Will it be said that I formerly held many things to be true and certain which I have afterwards recognized to be false? But I had not had any clear and distinct knowledge of these things, and not as yet knowing the rule whereby I assure myself of the truth, I had been impelled to give my assent from reasons which I have since recognized to be less strong than I had at the time imagined them to be. What further objection can then be raised? That possibly I am dreaming (an objection I myself made a little while ago), or that all the thoughts which I now have are no truer than the fantasies of my dreams? But even though I slept the case would be the same, for all that is clearly present to my mind is absolutely true.




Conception is Part of my Thinking Nature, but Imagination is Not

Nothing further now remains but to inquire whether material things exist. Certainly I at least know that these may exist in so far as they are considered as the objects of pure mathematics, since in this aspect I perceive them clearly and distinctly. . . . Further, the faculty of imagination which I possess, and of which, experience tells me, I make use when I apply myself to the consideration of material things, is capable of persuading me of their existence. For when I attentively consider what imagination is, I find that it is nothing but a certain application of the faculty of knowledge to the body which is immediately present to it, and which therefore exists.

            To make this quite clear, I remark in the first place the difference that exists between the imagination and pure intellection [or conception]. For example, when I imagine a triangle, I do not conceive it only as a figure comprehended by three lines, but I also see these three lines as present by the power and inward vision of my mind, and this is what I call imagining. But if I desire to think of a chiliagon, I certainly conceive truly that it is a figure composed of a thousand sides, just as easily as I conceive of a triangle that it is a figure of three sides only. But I cannot in any way imagine the thousand sides of a chiliagon [as I do the three sides of a triangle], nor do I, so to speak, regard them as present [with the eyes of my mind]. Although in accordance with the habit I have formed of always employing the aid of my imagination when I think of corporeal things, it may happen that in imagining a chiliagon I confusedly represent to myself some figure, yet it is very evident that this figure is not a chiliagon, since it in no way differs from that which I represent to myself when I think of a myriagon or any other many-sided figure. . . .

            I remark besides that this power of imagination which is in one, inasmuch as it differs from the power of understanding, is in no wise a necessary element in my nature, or in [my essence, that is to say, in] the essence of my mind. For although I did not possess it I should doubtless ever remain the same as I now am, from which it appears that we might conclude that it depends on something which differs from me. . . .


My Essence as a Thinking Thing

Now that I begin to know myself better, and to discover more clearly the author of my being, I do not in truth think that I should rashly admit all the matters which the senses seem to teach us, but, on the other hand, I do not think that I should doubt them all universally.

            First of all, because I know that all things which I perceive clearly and distinctly can be created by God as I understand them, it suffices that I am able to perceive one thing apart from another clearly and distinctly in order to be certain that the one is different from the other, since they may be made to exist in separation at least by the omnipotence of God. It does not signify by what power this separation is made in order to compel me to judge them to be different. Therefore, just because I know certainly that I exist, and that at the same time I do not note that any other thing necessarily pertains to my nature or essence, except that I am a thinking thing, I rightly conclude that my essence consists solely in the fact that I am a thinking thing [or a substance whose whole essence or nature is to think]. Although possibly (or rather certainly, as I will say in a moment) I possess a body with which I am very intimately conjoined, it is certain that this I [that is to say, my soul by which I am what I am], is entirely and absolutely distinct from my body, and can exist without it. This is because, on the one hand, I have a clear and distinct idea of myself inasmuch as I am only a thinking and unextended thing, and as, on the other, I possess a distinct idea of body, inasmuch as it is only an extended and unthinking thing.


Proof of External Objects: An External Active Faculty influences my Passive Faculty of Perception

I further find in myself faculties employing modes of thinking peculiar to themselves, namely, the faculties of imagination and feeling, without which I can easily conceive myself clearly and distinctly as a complete being. While, on the other hand, they cannot be so conceived apart from me, that is without an intelligent substance in which they reside, for [in the notion we have of these faculties, or, to use the language of the Schools] in their formal concept, some kind of intellection is comprised, from which I infer that they are distinct from me as its modes are from a thing. I observe also in me some other faculties such as that of change of position, the assumption of different figures and such like, which cannot be conceived, any more than can the preceding, apart from some substance to which they are attached, and consequently cannot exist without it. But it is very clear that these faculties, if it be true that they exist, must be attached to some corporeal or extended substance, and not to an intelligent substance, since in the clear and distinct conception of these there is some sort of extension found to be present, but no intellection at all. There is certainly further in me a certain passive faculty of perception, that is, of receiving and recognizing the ideas of sensible things. But this would be useless to me [and I could in no way benefit from it], if there were not either in me or in some other thing another active faculty capable of forming and producing these ideas.

            But this active faculty cannot exist in me [inasmuch as I am a thing that thinks] seeing that it does not presuppose thought, and also that those ideas are often produced in me without my contributing in any way to the same, and often even against my will. It is thus necessarily the case that the faculty resides in some substance different from me in which all the reality which is objectively in the ideas that are produced by this faculty is formally or eminently contained, as I remarked before. This substance is either a body, that is, a corporeal nature in which there is contained formally [and really] all that which is objectively [and by representation] in those ideas, or it is God himself, or some other creature more noble than body in which that same is contained eminently. But, since God is no deceiver, it is very evident that he does not communicate to me these ideas immediately and by himself, nor yet by the intervention of some creature in which their reality is not formally, but only eminently, contained. For since he has given me no faculty to recognize that this is the case, but, on the other hand, a very great inclination to believe [that they are sent to me or] that they are conveyed to me by corporeal objects, I do not see how he could be defended from the accusation of deceit if these ideas were produced by causes other than corporeal objects. Hence we must allow that corporeal things exist. However, they are perhaps not exactly what we perceive by the senses, since this comprehension by the senses is in many instances very obscure and confused. But we must at least admit that all things which I conceive in them clearly and distinctly, that is to say, all things which, speaking generally, are comprehended in the object of pure mathematics, are truly to be recognized as external objects. . . .


How to Explain Errors that result from Mechanical Causes of the Body

But we frequently deceive ourselves even in those things to which we are directly impelled by nature, as happens with those who when they are sick desire to drink or eat things hurtful to them. It will perhaps be said here that the cause of their deceptiveness is that their nature is corrupt. But that does not remove the difficulty, because a sick man is none the less truly God’s creature as he who is in health. It is therefore as repugnant to God’s goodness for the one to have a deceitful nature as it is for the other. As a clock composed of wheels and counter-weights no less exactly observes the laws of nature when it is badly made, and does not show the time properly, than when it entirely satisfies the wishes of its maker. I consider the body of a man as being a sort of machine so built up and composed of nerves, muscles, veins, blood and skin, that though there were no mind in it at all, it would not cease to have the same motions as at present. Exception are made for those movements which are due to the direction of the will, and in consequence depend upon the mind [as opposed to those which operate by the disposition of its organs]. I easily recognize that it would be as natural to this body, supposing it to be, for example, dropsical, to suffer the parchedness of the throat which usually signifies to the mind the feeling of thirst. It would be disposed by this parched feeling to move the nerves and other parts in the way required for drinking, and thus to augment its malady and do harm to itself, as it is natural to it, when it has no indisposition, to be impelled to drink for its good by a similar cause. Although, considering the use to which the clock has been destined by its maker, I may say that it deflects from the order of its nature when it does not indicate the hours correctly. As, in the same way, considering the machine of the human body as having been formed by God in order to have in itself all the movements usually manifested there, I have reason for thinking that it does not follow the order of nature when, if the throat is dry, drinking does harm to the conservation of health.

            Nevertheless I recognize at the same time that this last way of explaining nature is very different from the other. For this is but a purely verbal characterization depending entirely on my thought, which compares a sick man and a badly constructed clock with the idea which I have of a healthy man and a well-made clock, and it is hence extrinsic to the things to which it is applied. But according to the other interpretation of the term “nature” I understand something which is truly found in things and which is therefore not without some truth.

            But certainly although in regard to the dropsical body it is only so to speak to apply an extrinsic term when we say that its nature is corrupted, inasmuch as apart from the need to drink, the throat is parched. Yet in regard to the composite whole, that is to say, to the mind or soul united to this body, it is not a purely verbal predicate, but a real error of nature, for it to have thirst when drinking would be hurtful to it. Thus it still remains to inquire how the goodness of God does not prevent the nature of man so regarded from being fallacious.




Mind has no Parts, but Body has No Parts

To begin this examination, then, I say, in the first place, that there is a great difference between mind and body, inasmuch as body is by nature always divisible, and the mind is entirely indivisible. For, as a matter of fact, when I consider the mind, that is to say, myself inasmuch as I am only a thinking thing, I cannot distinguish in myself any parts, but understand myself to be clearly one and entire. Although the whole mind seems to be united to the whole body, yet if a foot, or an arm, or some other part, is separated from my body, I am aware that nothing has been taken away from my mind. The faculties of willing, feeling, conceiving, etc. cannot be properly speaking said to be its parts, for it is one and the same mind which employs itself in willing and in feeling and understanding. But it is quite otherwise with corporeal or extended objects, for there is not one of these imaginable by me which my mind cannot easily divide into parts, and which consequently I do not recognize as being divisible; this would be sufficient to teach me that the mind or soul of man is entirely different from the body, if I had not already learned it from other sources.


Mind receives Impressions Only from the Brain, Not Directly from Body Parts

I further notice that the mind does not receive the impressions from all parts of the body immediately, but only from the brain. Or perhaps it does this even from one of its smallest parts, namely, from that in which the common sense is said to reside, which, whenever it is disposed in the same particular way, conveys the same thing to the mind, although meanwhile the other portions of the body may be differently disposed, as is testified by innumerable experiments which it is unnecessary here to recount.


Long Nerves to the Brain Trigger Sensations at Any Spot

I notice, also, that the nature of body is such that none of its parts can be moved by another part a little way off which cannot also be moved in the same way by each one of the parts which are between the two, although this more remote part does not act at all. As, for example, in the cord ABCD [which is in tension] if we pull the last part D, the first part A will not be moved in any way differently from what would be the case if one of the intervening parts B or C were pulled, and the last part D were to remain unmoved. In the same way, when I feel pain in my foot, my knowledge of physics teaches me that this sensation is communicated by means of nerves dispersed through the foot, which, being extended like cords from there to the brain, when they are contracted in the foot, at the same time contract the inmost portions of the brain which is their extremity and place of origin, and then excite a certain movement which nature has established in order to cause the mind to be affected by a sensation of pain represented as existing in the foot. But because these nerves must pass through the tibia, the thigh, the loins, the back and the neck, in order to reach from the leg to the brain, it may happen that although their extremities which are in the foot are not affected, but only certain ones of their intervening parts [which pass by the loins or the neck], this action will excite the same movement in the brain that might have been excited there by a hurt received in the foot, in consequence of which the mind will necessarily feel in the foot the same pain as if it had received a hurt. The same holds good of all the other perceptions of our senses.


Some Misleading Perceptions Advance our Survival

I notice finally that each of the movements which are in the portion of the brain by which the mind is immediately affected brings about one particular sensation only. Consequently, we cannot under the circumstances imagine anything more likely than that this movement (among all the sensations which it is capable of impressing on it) causes the mind to be affected by that one which is best fitted and most generally useful for the conservation of the human body when it is in health. But experience makes us aware that all the feelings with which nature inspires us are such as I have just spoken of. There is therefore nothing in them which does not give testimony to the power and goodness of the God [who has produced them]. Thus, for example, when the nerves which are in the feet are violently or more than usually moved, their movement, passing through the medulla of the spine to the inmost parts of the brain, gives a sign to the mind which makes it feel somewhat, namely, pain, as though in the foot, by which the mind is excited to do its utmost to remove the cause of the evil as dangerous and hurtful to the foot. It is true that God could have constituted the nature of man in such a way that this same movement in the brain would have conveyed something quite different to the mind. For example, it might have produced consciousness of itself either in so far as it is in the brain, or as it is in the foot, or as it is in some other place between the foot and the brain, or it might finally have produced consciousness of anything else whatsoever. But none of all this would have contributed so well to the conservation of the body. Similarly, when we desire to drink, a certain dryness of the throat is produced which moves its nerves, and by their means the internal portions of the brain. This movement causes in the mind the sensation of thirst, because in this case there is nothing more useful to us than to become aware that we have need to drink for the conservation of our health. The same holds good in other instances. . . .


Solution: We Learn to Adjust to Misleading Perceptions

Certainly this consideration is of great service to me, not only in enabling me to recognize all the errors to which my nature is subject, but also in enabling me to avoid them or to correct them more easily. For, I know that all my senses more frequently indicate to me truth than falsehood respecting the things which concern that which is beneficial to the body. I am also almost always able to benefit from many of them in order to examine one particular thing. Besides that, I am able to make use of my memory in order to connect the present with the past, and of my understanding which already has discovered all the causes of my errors. Thus, I ought no longer to fear that falsity may be found in matters every day presented to me by my senses.


OBJECTIONS AND REPLIES (from Meditations, 1641, Objections and Replies)


Nothing New in the Skeptical Arguments of Meditation 1 (from Third Set of Objections)

            Objection [Hobbes]: It is sufficiently obvious from what is said in this Meditation, that we have no criterion for distinguishing dreaming from waking mid from what the senses truly tell us; and that hence the images present to us when we are awake and using our senses are not accidents inhering in external objects, and fail to prove that such external objects do as a fact exist. Therefore, if we follow our senses without using any train of reasoning, we will be justified in doubting whether or not anything exists. Hence we acknowledge the truth of this Meditation. But, since Plato and other ancient Philosophers have talked about this want of certitude in the matters of sense, and since the difficulty in distinguishing the waking state from dreams is a matter of common observation, I should had been glad if our author, so distinguished in the handling of modern speculations, had refrained from publishing those matters of ancient lore.

            Reply [Descartes]: The reasons for doubt here admitted as true by this Philosopher were propounded by me only as possessing verisimilitude, and my reason for employing them was not that I might retail them as new, but partly that I might prepare my readers' minds for the study of intellectual matters and for distinguishing them from matters corporeal, a purpose for which such arguments seem wholly necessary ; in part also because I intended to reply to these very arguments in the subsequent Meditations ; and partly in order to show the strength of the truths I afterwards propound, by the fact that such metaphysical doubts cannot shake them. Hence, while I have sought no praise from their rehearsal, I believe that it was impossible for me to omit them, as impossible as it would be for a medical writer to omit the description of a disease when trying to teach the method of curing it.


Whether “I Am” is Logically Deduced (from Second Set of Objections)

            Objection [Mersenne]: [At the outset of Meditation 2] you are not yet certain of the aforesaid existence of God. Yet, according to your statement, you cannot be certain of anything or know anything clearly and distinctly unless previously you know certainly and clearly that God exists. Thus, you cannot clearly and distinctly know that you are a thinking thing. For, according to you, that knowledge depends on the clear knowledge of the existence of God, the proof of which you have not yet reached at that point where you draw the conclusion that you have a clear knowledge of what you are.

            Reply [Descartes]: When I said that “we could know nothing with certainty unless we were first aware that God existed,” I announced in express terms that I referred only to the science of understanding such conclusions “as can recur in memory without attending further to the proofs which led me to make them.” Further, knowledge of the first principles is not usually called “science” by dialecticians. But when we become aware that we are thinking beings, this is a primitive act of knowledge derived from no syllogistic reasoning. He who says, “I think, hence I am, or exist,” does not deduce existence from thought by a syllogism. But by a simple act of mental vision, he recognizes it as if it were a thing that is known per se. This is evident from the fact that if it were syllogistically deduced, the major premise, “that everything that thinks is, or exists” would have to be known previously. But yet that has rather been learned from the experience of the individual, that unless he exists he cannot think. For our mind is so constituted by nature that general propositions are formed out of the knowledge of particulars.


Circular Reasoning regarding Claritity-Distinctness and Proof of God (from Fourth Set of Objections)

            Objection [Arnauld]: The only remaining scruple I have is an uncertainty as to how a circular reasoning is to be avoided in saying: "the only secure reason we have for believing that what we clearly and distinctly perceive is true, is the fact that God exists." But we can be sure that God exists, only because we dearly and evidently perceive that; therefore prior to being certain that God exists, we should be certain that whatever we clearly and evidently perceive is true.

            Reply [Descartes]: I may cite the explanations that I have already given at sufficient length in my reply to the second set of Objections, numbers 3 and 4. There I distinguished those matters that in actual truth we clearly perceive from those we remember to have formerly perceived. For first, we are sure that God exists because we have attended to the proofs that established this fact; but afterwards it is enough for us to remember that we have perceived something clearly, in order to be sure that it is true; but this would not suffice, unless we knew that God existed and that he did not deceive us.


Whether I am Not a Body (from Fourth Set of Objections)

            Objection [Arnauld]: Let us discover how, from this principle, we can demonstrate the fact that our mind is [distinct and] separate from our body. I am able to doubt whether I have a body, nay, whether any body exists at all; yet I have no right to doubt whether I am, or exist, so long as I doubt or think. Hence I, who doubt and think, am not a body; otherwise in entertaining doubt concerning body, I should doubt about myself. Nay, even though I obstinately maintain that no body at all exists, the position taken up is unshaken; I am something, hence I am not a body. This is really very acute, but someone could bring up the objection which our author urges against himself; the fact that I doubt about body or deny that body exists, does not bring it about that no body exists.

            Reply [Descartes]: Hence perhaps it happens that these very things which I suppose to be nothing, because they are unknown to me, yet do not in truth differ from that self which I do know. I know nothing about it, he says, I do not dispute this matter. [I can judge only about things that are known to me.] I know that I exist. I enquire who I, the known self, am. It is quite certain that the knowledge of this self thus precisely taken, does not depend on those things of the existence of which I am not yet acquainted.


How an Incorporeal Mind can Interact with a Corporeal Body (from Fifth Set of Objections)

            Objection [Gassendi]: It still remains to be explained, how that union and apparent intermingling, or confusion [[between mind and body]], can be found in you, if you are incorporeal, unextended and indivisible. For if you are not greater than a point, how can you be united with the entire body, which is of such great magnitude? How, at least, can you be united with the brain, or some minute part in it, which (as has been said) must yet have some magnitude or extension, however small it be? If you are wholly without parts, how can you mix or appear to mix with its minute subdivisions? For there is no mixture unless each of the things to be mixed has parts that can mix with each other. Further, if you are discrete, how could you be involved with and form one thing along with matter itself? Again since conjunction or union exists between certain parts, ought there not to be a relation of similarity between parts of this sort? But what must the union of the corporeal with the incorporeal be thought to be?. . . But, in a word, the general difficulty always remains, viz. how the corporeal can have anything in common with the incorporeal, or what relationship may be established between the one and the other.

            Reply [Descartes]: At no place do you bring an objection to my arguments; you only set forth the doubts which you think follow from my conclusions, though they arise merely from your wishing to subject to the scrutiny of the imagination matters which, by their own nature, do not fall under it. Thus when you wish to compare the union of mind and body with the mixture of two bodies, it is enough for me to reply that no such comparison ought to be set up, because the two things are wholly diverse, and we must not imagine that there are parts in mind because it is aware of parts in body. From where do you derive the conclusion that everything which mind knows must exist in mind? If that were so, then, when it was aware of the magnitude of the earth, it would be obliged to have that object within it, and consequently would not only be extended but greater in extent than the whole world.




I Think, Therefore I Am (from Discourse on the Method, 1637)

For a long time I had remarked that it is sometimes required in common life to follow opinions which one knows to be most uncertain, exactly as though they were indisputable, as has been said above. But because in this case I wished to give myself entirely to the search after Truth, I thought that it was necessary for me to take an apparently opposite course, and to reject as absolutely false everything as to which I could imagine the least ground of doubt, in order to see if afterwards there remained anything in my belief that was entirely certain. Thus, because our senses sometimes deceive us, I wished to suppose that nothing is just as they cause us to imagine it to be; and because there are men who deceive themselves in their reasoning and fall into paralogisms, even concerning the simplest matters of geometry, and judging that I was as subject to error as was any other, I rejected as false all the reasons formerly accepted by me as demonstrations. Since all the same thoughts and conceptions which we have while awake may also come to us in sleep, without any of them being at that time true, I resolved to assume that everything that ever entered into my mind was no truer than the illusions of my dreams. But immediately afterwards I noticed that while I thus wished to think all things false, it was absolutely essential that the "I" who thought this should be somewhat. Remarking that this truth "I think, therefore I am" was so certain and so assured that all the most extravagant suppositions brought forward by the skeptics were incapable of shaking it, I came to the conclusion that I could receive it without scruple as the first principle of the Philosophy for which I was seeking.


I Think, Therefore I Am (from Principles of Philosophy, 1644)

Principle 7. That we cannot doubt our existence without existing while we doubt; and this is the first knowledge that we obtain when we philosophize in an orderly way. While we thus reject all that of which we can possibly doubt, and assume that it is false, it is easy to suppose that there is no God, nor heaven, nor bodies, and that we possess neither hands, nor feet, nor indeed any body. But we cannot in the same way conceive that we who doubt these things are not. For there is a contradiction in conceiving that what thinks does not at the same time as it thinks, exist. Hence this conclusion I think, therefore I am, is the first and most certain of all that occurs to one who philosophizes in an orderly way.




31. That there is a small gland in the brain in which the soul exercises its function more particularly than in the other parts. It is likewise necessary to know that although the soul is joined to the whole body, there is yet in that a certain part in which it exercises its functions more particularly than in all the others. It is usually believed that this part is the brain, or possibly the heart. It is believed to be the brain because it is with it that the organs of sense are connected. It is believed to be the heart because it is apparently in it that we experience the passions. But, in examining the matter with care, it seems as though I had clearly ascertained that the part of the body in which the soul exercises its functions immediately is neither in the heart, nor the whole of the brain. Instead, it is merely the most inward of all its parts, namely, a certain very small gland which is situated in the middle of its substance and so suspended above the duct whereby the animal spirits in its anterior cavities have communication with those in the posterior. It is such that the slightest movements which take place in it may alter very greatly the course of these spirits. Reciprocally, the smallest changes which occur in the course of the spirits may do much to change the movements of this gland.

            32. How we know that this gland is the main seat of the soul. The soul cannot have any other seat in all the body than this gland wherein to exercise its functions immediately. The reason I am persuaded of this is that I reflect that the other parts of our brain are all of them double, just as we have two eyes two hands, two ears, and finally all the organs of our outside senses are double. We have but one solitary and simple thought of one particular thing at one and the same moment. Thus, there must somewhere be a place where the two images which come to us by the two eyes, where the two other impressions which proceed from a single object by means of the double organs of the other senses, can unite before arriving at the soul, in order that they may not represent to it two objects instead of one. It is easy to see how these images or other impressions might unite in this gland by the intermission of the spirits which fill the cavities of the brain. But there is no other place in the body where they can be thus united unless they are so in this gland.

            34. How the soul and the body act on each other. Let us then conceive here that the soul has its principal seat in the little gland which exists in the middle of the brain. For, from this spot it radiates forth through all the remainder of the body by means of the animal spirits, nerves, and even the blood, which, participating in the impressions of the spirits, can carry them by the arteries into all the members. Recall what has been said above about the machine of our body, that is, that the little filaments of our nerves are so distributed in all its parts, that on the occasion of the diverse movements which are there excited by sensible objects, they open in different ways the pores of the brain. This, in turn, causes the animal spirit contained in these cavities to enter in different ways into the muscles, by which means they can move the members in all the different ways in which they are capable of being moved. Also, recall all the other causes which are capable of moving the spirits in different ways and which suffice to conduct them into different muscles. Let us here add that the small gland which is the main seat of the soul is so suspended between the cavities which contain the spirits that it can be moved by them in as many different ways as there are sensible differences in the object.

            Further, it may also be moved in different ways by the soul, whose nature is such that it receives in itself as many different impressions, that is to say, that it possesses as many different perceptions as there are different movements in this gland. Reciprocally, likewise, the machine of the body is so formed that from the simple fact that this gland is differently moved by the soul (or by such other cause, whatever it is) it thrusts the spirits which surround it towards the pores of the brain, which conduct them by the nerves into the muscles, by which means it causes them to move the limbs.


THE AUTOMATISM OF ANIMALS (Letter, Descartes to Henry More, 1649)

The greatest of all prejudices we have retained from infancy is that of believing that animals think. The source of our error comes from having observed that many of the bodily members of animals are not very different from our own in shape and movements. The mistake also comes from the belief that our mind is the principle of motions that occur in us, and that it imparts motion to the body and is the cause of our thoughts. Assuming this, we find no difficulty in believing that there is in animals a mind similar to our own. But, after thinking well upon it, I have made the discovery that two different principles of our movements are to be distinguished. The one is entirely mechanical and corporeal, and depends solely on the force of the animal spirits and the configuration of the bodily parts; this may be called corporeal soul. The other is incorporeal, that is to say, mind or soul, which you may define as a substance which thinks. I have inquired with great care whether the motions of animals proceed from these two principles or from one alone. Now, having clearly perceived that they can proceed from one only, I have held it demonstrated that we are not able in any manner to prove that there is in animals a soul that thinks.

            I am not at all disturbed in my opinion by those deceitful and cunning tricks of dogs and foxes, nor by all those things which animals do, either from fear, or to get something to eat, or just for sport. I maintain to explain all that very easily, merely by the conformation of the parts of the animals. Nevertheless, although I regard it as a thing demonstrated that it cannot be proved that animals have thought, I do not think that it can be demonstrated that the contrary is not true [i.e., we cannot prove that animals lack thought], because the human mind cannot penetrate into the heart to know what goes on there. But on examining into the probabilities of the case, I see no reason whatever to prove that animals think. One possible reason is that by having eyes, ears, a tongue, and other organs of sense like ours, it is likely that they have sensations as we do; and as thought is involved in the sensations which we have, a similar faculty of thought must be attributed to them. Now, since this argument is within the reach of everyone’s capacity, it has held possession of all minds from infancy. But there are other stronger and more numerous arguments for the opposite opinion, which do not so readily present themselves to everybody’s mind. For example, it is more reasonable to make earthworms, flies, caterpillars, and the rest of the animals move as machines do, than to give them immortal souls.

            It is certain that in the body of animals, as in ours, there are bones, nerves, muscles, blood, animal spirits, and other organs which are given in such a manner that they can produce themselves without the aid of any thought. All the movements which we observe in animals are as appears in convulsive movements, as when in spite of the mind itself, the machine of the body moves often with greater violence, and in more various ways than it is accustomed to do with the aid of the will. Further, humans are able to construct different automata in which there is movement without any thought. In as much as it is agreeable to reason that art should imitate nature, nature, on her part, might produce these automata, and far more excellent ones as the animals are, than those which come from the hands of people. Thus, there is no reason anywhere why thought is to be found wherever we perceive a conformity of bodily members like that of the animals. It is more surprising that there should be a soul in every human body than that there should be none at all in the animals.

            But the principal argument to my mind, which may convince us that animals are devoid of reason is this. Among animals of the same species, some are more perfect than others, as among people. This is particularly noticeable in horses and dogs, some of which have more capacity than others to retain what is taught them. All of them make us clearly understand their natural movements of anger, of fear, of hunger, and others of like kind, either by the voice or by other bodily motions. However, it has never yet been observed that any animal has arrived at such a degree of perfection as to make use of a true language. That is to say, they have not been able to indicate to us by the voice, or by other signs anything which could be referred to thought alone, rather than to a movement of mere nature. For the word is the sole sign and the only certain mark of the presence of thought hidden and wrapped up in the body. Now, all people, the most stupid and the most foolish, those even who are deprived of the organs of speech, make use of signs, whereas the animals never do anything of the kind. This may be taken as the true distinction between humans and animals.

            . . . It must, however, be observed that I speak of the thought of animals, not of their life, nor of their sensation. For I do not deny the life of any animal when making it consist solely in the warmth of the heart. I do not refuse to them feeling even, in so far as it depends only on the bodily organs. Thus, my opinion is not so cruel to animals as it is favorable to humans. I speak to those who are not committed to the extravagant position of Pythagoras, who held people under suspicion of a crime if they ate or killed animals.


Questions for Review

1. In Descartes' Discourse on the Method, what the Four Rules of logical method?

2. In the Discourse on the Method, what are the four principles in the provisional code of morals?

3. In Meditation 1, what are the three doubting hypotheses?

4. In Meditation 2, why can't Descartes say that his identity is that of a rational animal or a union of body and soul?

5. In Meditation 2, what is the list of features of that are involved in being a thinking thing?

6. In Meditation 2, why is the sameness of the wax not determined by the senses or imagination?

7. In Meditation 3, what is Descartes' causal principle and what are the two consequences that follow from it?

8. In Meditation 3, what is the proof for God's existence?

9. In Meditation 3, what is the reason that God is not a deceiver?

10. In Meditation 4, in what way is the human will is like God's?

11. In Meditation 4, what is Descartes' explanation for how error arises?

12. In Meditation 4, why can't we blame God for giving us limited knowledge or a boundless will?

13. In Meditation 5, what is the reason why we can maintain confidence in long proofs even after we forget the details?

14. In Meditation 6, what how do conception (intellection) and imagination differ?

15. In Meditation 6, what is the proof of external objects?

16. In Meditation 6, what are the four sources of error that come from the body?

17. In the Objections and Replies, what is Descartes' reply to the objection about whether "I am" is logically deduced?

18. In the Objections and Replies, what is Descartes' reply to the objection concerning circular reasoning regarding clarity-distinctness and proof of God?

19. In the Objections and Replies, what is Descartes' reply to the objection concerning whether one's identity is not that of a body?

20. In Passions of the Soul, what are Descartes' reasons for believing that the pineal gland is the gateway between ones' brain and soul?

21. In his letter to Henry More, what reasons does Descartes give for denying a thinking soul to animals?


Questions for Analysis

1. Leibniz criticizes Descartes' method in the following: "Regarding the four Cartesian rules of method. . . . I do not see why they are unique to Descartes. I am close to saying that they are similar to the precepts of some sort of chemist: take what you need, and do what you should, and you will get what you want. . . . . The Cartesians are mistaken when they think they find the method or the art of discovery in Descartes' writings. As he himself said somewhere in his letters, he suppressed it and did not publish either a method or the method, but declared that he only wished to give an example. Even if Descartes had not stated this, the situation would speak for itself since there is no other explanation for why so many [Cartesian] men made no discovery of importance" (Leibniz's Works, Gerhardt, 1880, v. 4, 323 ff). Is Leibniz correct that Descartes' four rules say nothing of value? Explain.

2. In the "Objections to the Meditations," Hobbes criticized that the discussions of skepticism in Meditation 1 were sufficiently proposed and answered by ancient philosophers. Descartes replied that "my reason for employing them was not that I might retail them as new, but partly that I might prepare my readers' minds for the study of intellectual matters and for distinguishing them from matters corporeal." That is, even in the three doubting hypotheses there lurks a distinction between body and mind. Discuss this point in relation to the three doubting hypotheses.

3. The Ancient Greek Academic skeptics suggested the idea that God might be deceiving us, as indicated in the following passage from Cicero: "The skeptics try to show that many things can appear to exist, which in reality have no existence; when minds are moved to no purpose by things which do not exist, in the same manner as by things that do. For when you say (they say) that some visions are sent by God . . . they ask how God can make those things probable which appear to be false; and how it is that he cannot make those appear so which plainly come as near as possible to truth? Or if he can likewise make those appear probable, why he cannot make the others appear so too, which are only with great difficulty distinguished from them? And if he can make these appear so, then why he cannot also make those things appear so which are absolutely different in no respect whatever?" (Cicero, Academic Questions, 1.18). Compare and contrast Descartes' evil genius hypotheses to this view in the Academic skeptics.

4. The readings above contain several versions of Descartes' famous statement "I think therefore I am" from the Discourse on the Method (1637), The Meditations (1641), the "Objections" to the Meditations (1641), and The Principles of Philosophy (1644). Discuss the differences between them, especially in light of his comments in the "Objections".

5. Descartes' reasoning behind "I think therefore I am" was borrowed from Augustine who stated the following "Without any delusive representation of images or phantasms, I am most certain that I am, and that I know and delight in this. In respect of these truths, I am not at all afraid of the arguments of the Academicians, who say, What if you are deceived? For if I am deceived, I am. For he who is not, cannot be deceived; and if I am deceived, by this same token I am. Since I am if I am deceived, how am I deceived in believing that I am? for it is certain that I am if I am deceived. Since, therefore, I, the person deceived, should be, even if I were deceived, certainly I am not deceived in this knowledge that I am. Consequently, neither am I deceived in knowing that I know. For, as I know that I am, so I know this also, that I know" (City of God, 11:26). Contemporary Descartes scholar Catherine Wilson states the following: "Although Augustine took himself to be demonstrating that he was alive rather than that he simply existed, the argumentation is similar [to Descartes']" ("Descartes and Augustine," 2008). Is Wilson correct? Discuss the similarities and differences between Descartes and Augustine on this issue.

6. A key premise in Descartes' proof for God's existence in Meditation 3 is that there must be at least as much objective reality in the cause of an idea as in the idea itself. In his reply to the second set of objections (not included above), Descartes defines "objective reality" as follows: "By the objective reality of an idea I mean that in respect of which the thing represented in the idea is an entity, insofar as that exists in the idea; and in the same way we can talk of objective perfection, objective device, etc. For whatever we perceive as being as it were in the objects of our ideas, exists in the ideas themselves objectively." Explain Descartes' definition and how that concept factors into his proof for God.

7. John Stuart Mill makes the following criticism of Descartes' principle of causality in Meditation 3: "Descartes, in like manner, whose works are a rich mine of almost every description of a priori fallacy, says that the Efficient Cause must at least have all the perfections of the effect, and for this singular reason: 'if we imagine that something is found in an idea which is not found in the cause, it must then have been derived from nothing' of which it is scarcely a parody to say, that if there be pepper in the soup there must be pepper in the cook who made it, since otherwise the pepper would be without a cause" (System of Logic, 1843, 5.3.8). Explain Mill’s criticism and how Descartes might reply.

8. John Stuart Mill makes the following criticism of Descartes’ proof for God in Meditation 3. “The conception, says he, of an infinite Being proves the real existence of such a being. For if there is not really any such being, I must have made the conception; but if I could make it, I can also unmake it; which evidently is not true; therefore there must be, externally to myself, an archetype, from which the conception was derived. In this argument (which, it may be observed, would equally prove the real existence of ghosts and of witches) the ambiguity is in the pronoun I, by which, in one place, is to be understood my will, in another the laws of my nature. If the conception, existing as it does in my mind, had no original without, the conclusion would unquestionably follow that I made it; that is, the laws of my nature must have somehow evolved it: but that my will made it, would not follow” (System of Logic, 1843, 5.7.1). Explain Mill’s criticism and how Descartes might reply.

9. In Meditation 6, Descartes argues that his essence and identity is that of a thinking thing. The objection by Arnauld in the fourth set of objections discusses this point. Discuss Descartes' reasoning and Arnauld's objection.

10. Descartes argues that the pineal gland within the brain is the interactive gateway between the brain and the soul. Discus the criticism of this in the Objections and Replies, and whether Descartes's reply is adequate.