Discourse on Method and Meditations on First Philosophy

“I shall say nothing about philosophy, except that, seeing that it has been cultivated by the very best minds which have ever existed over several centuries and that, nevertheless, not one of its problems is not subject to disagreement, and consequently is uncertain, I was not presumptuous enough to hope to succeed in it any better than others, and seeing how many different opinions are sustained by learned men about one item, without its being possible for more than one ever to be true, I took to be tantamount to false everything which was merely probable. As for the other sciences, in so far as they borrow their principles from philosophy, I consider that nothing solid could have been built on such shifting foundations; and neither the honour nor the material gain held out by them was sufficient to induce me to study them.”

In this passage, Descartes is describing his experience of studying philosophy at university. This experience was formative for Descartes precisely because it taught him that the history of philosophy is populated less with answers that are absolutely and irrefutably true and more with a wide variety of differing positions, even with respect to a single topic. In this regard, says Descartes, we should not look to philosophy as it is taught in the university to provide us access to a true understanding of ourselves, God, and the world, since academic philosophy itself cannot even settle upon an agreed-upon solution to key philosophical problems. 

“Among these one of the first I examined was that often there is less perfection in works composed of several separate pieces and made by different masters, than in those at which only one person has worked.”

In this passage, Descartes is outlining a commonly-held idea during this period of early Modern Rationalism: if only clear and distinct ideas are the most likely to be true, then ideas that are simplified are the best starting points in the search for truth. Additionally, Descartes’s form of argumentation here is what is sometimes referred to as the craft argument, which states that a work or idea authored by a single person is more likely to access more of the truth, rather than a work or idea authored by many, since the conflicting interests and visions of the many will sully or obscure whatever degree of truth each individual may be able to possess.

“[…] it is indeed certain that the state of the true religion, the laws of which God alone has made, must be incomparably better ordered than all others. And, to speak of human things, I believe that, if Sparta greatly flourished in times past, it was not on account of the excellence of each of its laws taken individually, seeing that many were very strange and even contrary to good morals, but because, having been invented by one man only, they all tended towards the same end.”

In this passage, Descartes is reiterating the craft argument from the passage above but with an important addition: the contrast between human laws and divine law. This is important since it will allow Descartes to posit God as a model and criteria for what is indubitably true and therefore aspire toward holding only those opinions and beliefs that could be held by the mind of God himself. 

“The first was never to accept anything as true that I did not know to be evidently so: that is to say, carefully to avoid precipitancy and prejudice, and to include in my judgments nothing more than what presented itself so clearly and so distinctly to my mind that I might have no occasion to place it in doubt. The second, to divide each of the difficulties that I was examining into as many parts as might be possible and necessary in order best to solve it. The third, to conduct my thought in an orderly way, beginning with the simplest objects and the easiest to know, in order to climb gradually, as by degrees, as far as the knowledge of the most complex […] And the last, everywhere to make such complete enumerations and such general reviews that I would be sure to have omitted nothing.”

In this passage, Descartes is outlining the four key principles that will ground his philosophical method: 1) subject every opinion to doubt; 2) breakdown every opinion into as many assumptions as possible, in order to analyze each and understand its proper place within the chain of reasoning that would lead an individual to take such an opinion as true; 3) begin with the most simple ideas and then work one’s way up to the most complex; and 4) continuously subject every conclusion one reaches to scrutiny and revision in order to avoid unjustified beliefs. These four principles are a direct extension of his philosophical predecessors, perhaps most notably the notion of Ockham's Razor, which is the idea that states the most rational means of reaching true ideas is through the simplification of the object of rational inquiry.

“[…] many do not themselves know what they believe; for the action of thought by which one believes a thing, being different from that by which one knows that one believes it, they often exist the one without the other.”

In this passage, Descartes is making a distinction between what people think they know and how people prove, or justify, how they know what they do. In other words, Descartes is making a distinction between unjustified beliefs and justified beliefs. The former is the class of beliefs that we hold to be true but cannot say why they are true. The latter is the class of beliefs that we take to be true while being able to provide the reasons for why we hold them to be true. 

“Then, examining attentively what I was, and seeing that I could pretend that I had no body and there was no world or place that I was in, but that I could not, for all that, pretend that I did not exist, and that, on the contrary, from the very fact that I thought of doubting the truth of other things, it followed very evidently and very certainly that I existed [...] I thereby concluded that I was a substance, of which the whole essence or nature consists in thinking, and which, in order to exist, needs no place and depends on no material thing; so that this ‘I,’ that is to say, the mind, by which I am what I am, is entirely distinct from the body, and even that it is easier to know than the body, and moreover, that even if the body were not, it would not cease to be all that it is.”

In this passage, Descartes is establishing the doctrine for which he will become most famous: mind-body dualism. This doctrine claims that the mind and the body are two qualitatively different entities and, for Descartes, while we cannot be certain of the existence of our body (since all the knowledge we gain from sensory experience can be deceptive and illusory) we can know, with certainty, the existence of our mind, since even if we doubt everything, the fact that we continue to doubt proves that we are the kind of being that doubts and therefore thinks. 

“[…] considering that all the same thoughts that we have when we are awake can also come to us when we are asleep […] I resolved to pretend that nothing which had ever entered my mind was any more true than the illusions of my dreams. But immediately afterwards I became aware that, while I decided thus to think that everything was false, it followed necessarily that I who thought thus must be something; and observing that this truth: I think, therefore I am, was so certain and so evident that all the most extravagant suppositions of the sceptics were not capable of shaking it, I judged that I could accept it without scruple as the first principle of the philosophy I was seeking.”

In this passage, Descartes is providing a general description of how he arrived at the certain truth of his existence. Descartes gives a general overview since he will provide a more detailed account in his Meditations on First Philosophy. In his Discourse on Method, the aim is to show that after utilizing doubt as a method for eliminating all previously-accepted opinions that, under closer scrutiny, were found to be dubitable to a greater or lesser degree, one can still have a certain belief in the existence of the human mind or soul. The reason for this is that even if we were to doubt everything that exists, including our own existence, the fact that there is something that doubts in the absence of everything else indicates that not only do we continue to exist but that we are the agents of this doubting. 

“[…] I decided to inquire whence I had learned to think of something more perfect than myself and I clearly recognized that this must have been from some nature which was in fact more perfect. As for the notions I had of several other things outside myself, such as the sky, the earth, light, heat and a thousand others, I had not the same concern to know their source, because, seeing nothing in them which seemed to make them superior to myself, I could believe that, if they were true, they were dependencies of my nature, in as much as it had some perfection; and, if they were not, that I held them from nothing, that is to say that they were in me because of an imperfection in my nature. But I could not make the same judgement concerning the idea of a being more perfect than myself, for to hold it from nothing was something manifestly impossible; and because it is no less contradictory that the more perfect should proceed from and depend on the less perfect, than it is that something should emerge out of nothing, I could not hold it from myself; with the result that it remained that it must have been put into me by a being whose nature was truly more perfect than mine and which even had in itself all the perfections of which I could have any idea, that is to say, in a single word, which was God.”

In this passage, Descartes is elaborating on the distinction between finite (or imperfect) things and infinite (or perfect) things. For Descartes, with respect to the ideas we have of finite things, such as sky, earth, light, and heat, we cannot distinguish with certainty between the real existence of the sky as a mind-independent phenomenon and not simply a hallucination of the mind. However, with respect to the idea we have of infinite things such as God, Descartes argues that because he (Descartes)possesses the idea of infinity, and because the existence of the idea of an infinite perfect being cannot be predicated on the existence of a finite entity, the idea of God as an infinitely-perfect being must exist independently from the existence of the finite human mind. It is in this way that Descartes proves the existence of God.

“[…] for example, I very well perceived that, supposing a triangle to be given, its three angles must be equal to two right angles, but I saw nothing, for all that, which assured me that any such triangle existed in the world; whereas, reverting to the examination of the idea I had of a perfect Being, I found that existence was comprised in the idea in the same way that the equality of the three angles of a triangle to two right angles is comprised in the idea of a triangle or, as in the idea of a sphere, the fact that all its parts are equidistant from its centre, or even more obviously so; and that consequently it is at least as certain that God, who is this perfect Being is, or exists, as any geometric demonstration can be. But what persuades many people that it is difficult to know this […] is that they never lift their minds above tangible things, and that they are so accustomed not to think of anything except by imagining it, which is a mode of thinking peculiar to material objects, that everything which is not within the realm of imagination seems to them unintelligible.”

In this passage, Descartes is arguing that the nature and existence of God is akin to that of mathematical theorems and objects such as a triangle. Just as it remains true that a triangle is a three-sided shape equaling 180 degrees that can never be encountered in the natural world, God is a perfect being whose essence entails its existence. Moreover, the connection between mathematical truth and philosophical truth is seen clearest in passages such as these. For Descartes, what is true beyond all possible doubt are those principles that correspond to what is logically necessary, rather than those ideas we have which correspond to objects or describe the world. Thus, the kind of truth Descartes is after is logical and not descriptive.

“[…] I could not keep them [Descartes’ discoveries] hidden without sinning considerably against the law which obliges us to procure […] the general good of all men. For they have made me see that it is possible to arrive at knowledge which is most useful in life, and that, instead of the speculative philosophy taught in the Schools, a practical philosophy can be found by which, knowing the power and the effects of fire, water, air, the stars, the heavens and all the other bodies which surround us, as distinctly as we know the various trades of our craftsmen, we might put them in the same way to all the uses for which they are appropriate, and thereby make ourselves, as it were, masters and possessors of nature.”

In this passage, Descartes is outlining how his theoretical discoveries regarding the existence of God, the existence of the mind as a thinking thing, and the existence of the human soul can inform more practical human affairs. For Descartes, it is not a problem that the existence of God as an idea fails to correspond to any given object or experience we have of the world. Rather, these ideas are significant because they are ideas that provide the correct order to reasoning about the world and our experiences therein. Thus, God, the self as thinking substance, and the immortal soul are ways of establishing the correct use of our cognitive faculty in light of the fact that, when it comes to practical and corporeal matters such as nature, and regardless of the inevitability of the trial and error of the scientific method, we will always be able to understand the correct placement of our conclusions regarding the world because we understand that perfection precedes imperfection, infinity precedes finitude, and so forth. 

“Everything I have accepted up to now as being absolutely true and assured, I have learned from and through the senses. But I have sometimes found that these senses played me false, and it is prudent never to trust entirely those who have once deceived us. But […] there are perhaps many other things about which one cannot reasonably doubt, although we know them through the medium of the senses, for example, that I am here, sitting by the fire, wearing a dressing-gown, with this paper in my hands, and other things of this nature. And how could I deny that these hands and this body belong to me, unless perhaps I were to assimilate myself to those insane persons [...] However, I must consider that I am a man, and consequently that I am in the habit of sleeping and of representing to myself in my dreams those same things, or sometimes even less likely things […] How many times have I dreamt at night that I was in this place, dressed, by the fire, although I was quite naked in my bed?”

In this passage, Descartes is outlining the necessity to doubt all knowledge that has been acquired through lived experience (or through our senses). As he states, and as will be a recurring theme through the whole of this text, we must doubt all knowledge received from experience because the senses themselves are an unreliable means of knowing, with certainty, the nature of reality and grasping what is true. Thus, if the task is to establish those truths that are beyond all possible doubt, anything we have taken to be true that has been acquired through sense experience will be treated as uncertain and therefore false. 

“I shall suppose, therefore, that there is, not a true God, who is the sovereign source of truth, but some evil demon, no less cunning and deceiving than powerful, who has used all his artifice to deceive me.”

Here, we see Descartes doubt the nature of God’s existence. Typically, and within the Judeo-Christian cosmology, God’s nature has always been understood as all-powerful, all-knowing, and all-benevolent, infinite and eternal in nature. However, because Descartes’s method of doubt is employed as his means of eliminating all unjustified beliefs from his mind, he must not only question the existence of God but his nature as well. Hence, as seen here, if God exists, says Descartes, we still do not know his essence, and thus must entertain the possibility of his being an evil demon as opposed to a benevolent shepherd of humanity.

“But there is some deceiver both very powerful and very cunning, who constantly uses all his wiles to deceive me. There is therefore no doubt that I exist, if he deceives me; and let him deceive me as much as he likes, he can never cause me to be nothing, so long as I think I am something. So that, after having thought carefully about it, and having scrupulously examined everything, one must then, in conclusion, take as assured that the proposition: I am, I exist, is necessarily true, every time I express it or conceive of it in my mind.”

This is a rather famous passage from Descartes’s Meditations known as the “evil genius” argument. This argument proposes the idea that while Descartes has in fact doubted everything, even the existence of a benevolent God (and therefore a malevolent divine being who deceives him), Descartes can still be certain of the fact of his existence. Why? Precisely because to be perpetually deceived presupposes the existence of a being who can be deceived (i.e. finite imperfect beings such as the human mind). Hence, says Descartes, even without the certainty of a benevolent creator, we can still be certain of the fact of our existence beyond any possible doubt.

“But as to myself, who am I, now that I suppose there is someone who is extremely powerful and, if I may so say, malicious and cunning, who employs all his efforts and industry to deceive me? Can I be sure of having the least of all the characteristics that I have attributed above to the nature of bodies? I pause to think about it carefully […] and I cannot find one of which I can say that it is in me […] Let us pass, then, to the attributes of the soul, and see if there are any of these in me. The first are eating and walking; but if it is true that I have no body, it is true also that I cannot walk or eat. Sensing is another attribute, but again this is impossible without the body; besides, I have frequently believed that I perceived in my sleep many things which I observed, on awakening, I had not in reality perceived. Another attribute is thinking, and I here discover an attribute which does belong to me; this alone cannot be detached from me. I am, I exist: this is certain; but for how long? For as long as I think, for it might perhaps happen, if I ceased to think, that I would at the same time cease to be or to exist. I now admit nothing which is not necessarily true: I am therefore, precisely speaking, only a thing which thinks, that is to say, a mind, understanding, or reason, terms whose significance was hitherto unknown to me.”

In this passage, Descartes clarifies the implications of his statement “I think, therefore I am.” According to Descartes, a question necessarily follows from this idea: namely, if it is beyond doubt that he (Descartes) exists, then what must be clarified is the nature of his existence—what kind of being is he? For Descartes, one cannot be certain in saying that one is an embodied being since knowledge acquired from the body can still deceive us and lead us to error. Moreover, because thinking is an attribute or characteristic of the mind and not the body, Descartes concludes that he is a thinking thing. In other words, while one may not be certain of the existence of one’s body, one can be absolutely certain as to the existence of one’s mind, since the mind (or soul) is the seat of our cognitive capacities.

“But to speak precisely, what is it that I imagine when I conceive it in this way? Let us consider it attentively, and setting aside everything that does not belong to the wax, let us see what remains. Indeed nothing remains, except something extended, flexible and malleable. Now, what does that mean: flexible and malleable? Is it not that I imagine that this wax, being round, is capable of becoming square, and of passing from a square to a triangular figure? No indeed, it is not that, for I conceive of it as capable of undergoing an infinity of similar changes, and as I could not embrace this infinity by my imagination, consequently this conception I have of the wax is not the product of the faculty of imagination.”

This is a famous passage from Descartes’s Second Meditation, where the reader encounters him subjecting all of the knowledge he has acquired through sense experience to doubt. This passage is significant when read in light of his conclusion that all he can say for certain is that he is a thinking, as opposed to corporeal, thing. The reason for this is that, for Descartes, corporeal things, such as the ball of wax, are of an indeterminate nature—corporeal things can change in shape, size, color, and form. Thus, concludes Descartes, we cannot be certain of the nature of corporeal things since they are always subject to change or slight modification. 

“I have often noticed in many cases, that there was a great difference between the object and its idea. Thus, for example, I find in my mind two quite different ideas of the sun: the one by which it appears to me extremely small, derives from the senses, and must be placed in the category of those which I said above come from outside; the other, by which it appears to me to be several times larger than the whole earth, is based upon the reasons of astronomy, is drawn, that is to say, from certain notions born with me, or formed by me in some way or other. Certainly these two ideas which I conceive of the sun cannot both resemble the same sun, and reason makes me believe that the idea which derives immediately from its appearance is the one which is most dissimilar.”

In this passage, Descartes is making a key distinction between ideas and the objects to which they correspond. For Descartes, the idea of the sun and the actual sun are two qualitatively different phenomena. While the idea of the sun as small is relative to our perspective on earth and therefore an inaccurate description, the latter, being the actual object, contains the reality and truth of the sun’s actual size and mass. Therefore, says Descartes, the ideas we have about objects only correspond to those ideas themselves.

“From all this I perceive that neither the power of willing which I have received from God is in itself the cause of my errors, for it is very ample and perfect of its kind; nor is the power of understanding or conceiving, for, conceiving nothing except by means of the faculty which God has given me, without doubt all that I conceive I conceive correctly, and it is impossible for me to be deceived in it. Whence, then, arise my errors? From this fact alone, that the will being much more ample and extended than the understanding, I do not contain it within the same limits, but extend it also to things I do not understand, and the will being of itself indifferent to such things, very easily goes astray and chooses the bad instead of good, or the false instead of the true, which results in my falling into error or sinning.”

In this key passage, Descartes ascribes the source of our errors to a misuse of our faculty of willing, which he defines as our ability to assent to something as being true. Thus, it is not God but the improper use of our powers of judging our own experiences that give rise to errors in our thinking. 

“But if I abstain from giving my judgement on a thing when I do not conceive it clearly and distinctly enough, it is evident that I act rightly and am not deceived; but if I decide to deny or affirm it, then I no longer make use as I should of my free will; and if I affirm what is false, it is evident that I am deceived, and even though I judge according to the truth, it is only by chance, and I am none the less at fault and misuse my free will’ for the natural light teaches us that the knowledge of the understanding must always precede the determination of the will.”

In this passage, Descartes is outlining the correct use of our intellect in moments when we cannot be sure as to the nature of our experiences. Error arises from the misuse of our will. Thus, as seen in this passage above, in moments when certainty is not present in our mind regarding the nature of experience, the correct action to take is to withhold our judgment.

“As for privation, in which alone consists the formal reason of error and sin, it has need of the concurrence of God, since it is not a thing or a being, and if it is referred back to God as to its cause, it should not be called privation, but only negation […] For, in truth, it is not an imperfection in God, that he has given me the freedom to give my judgement, or to withhold it, concerning things of which he has not put a clear and distinct knowledge into my understand; but undoubtedly it is an imperfection in me that I do not use it well, and give my judgment rashly on things which I perceive only obscurely and confusedly.”

In this passage, Descartes is relating his understanding of the source of errors to the existence of God. For Descartes, it is necessary to inquire into the possibility that it is God, and not our mind, that is the cause of our errors in how we come to know the world. However, as Descartes argues, to attribute error and deception to God would be to claim that the essence of God is both perfection and imperfection. Moreover, it would mean that God has not in fact granted human beings freewill. Thus, to imagine God as the source of our error and wrongdoing contradicts the very nature and existence of God, thereby showing that it must be the human mind that is the cause for its own errors.

“For being accustomed in all other matters to distinguish between existence and essence, I am easily persuaded that the existence of God can be separated from his essence and that, thus, God may be conceived as not actually existing. But, nevertheless, when I think about it more attentively, it becomes manifest that existence can no more be separated from the essence of God than the fact that the sum of its three angles is equal to two right-angles can be separated from the essence of a triangle or than the idea of a mountain can be separated from the idea of a valley; so that there is no less contradiction in conceiving a God, that is to say, a supremely perfect being, who lacks existence, that is to say, who lacks some particular perfection, than in conceiving a mountain without a valley.”

This passage is a key development in Descartes’s argument for the proof of the existence of God. As first seen in the Third Meditation, God was said to exist merely based on the inference that imperfect beings could not be the cause of or the reason for the existence of the idea of a perfect being. Here, in the Fifth Meditation, Descartes provides the reader with an argument for the self-evidence of God’s existence and does so by utilizing the distinction between existence and essence. So, for example, we can say that the essence of a human being is to be rational, capable of language, and to be social. Not included in this definition is the particular quantity or number of human beings that exist. In other words, particularity and quantity are irrelevant to the essence of human beings. Therefore, the essence of human beings is distinct from their concrete existence. By contrast, says Descartes, the idea of God, defined as a perfect being, necessarily entails God’s existence, since to not exist would be an imperfection or degradation of God’s perfection. Therefore, the essence of God is inseparable from the existence of God.

“[...] if I wish to think of a chiliagon, I indeed rightly conceive that it is a figure composed of a thousand sides, as easily as I conceive that a triangle is a figure composed of only three sides; but I cannot imagine the thousand sides of a chiliagon, as I do the three of a triangle, neither, so to speak, can I look upon them as present with the eyes of my mind.”

This passage is a variation on the distinction used by Descartes between essence and existence. In this passage, Descartes is using the example of a chiliagon, a thousand-sided polygon, as a way of analogously demonstrating how the truth of a given idea, such as a chiliagon, does not depend on whether or not such an object can be verified by our experiences. Similarly, and due to Descartes’s background in mathematics, geometrical proofs and mathematical theorems remain true regardless of the fact that one will never find a perfect triangle in nature. Moreover, the fact that a thousand-sided figure exceeds our capacity of imagination is proof, for Descartes, of the fact that knowing the essence of something is not equivalent or dependent upon being able to imagine its existence. 

“[...] outside myself, besides the extension, figure and movements of bodies, I noticed in them hardness, heat and all the other qualities which come under the sense of touch. Moreover, I observed in them light, colours, smells, tastes and sounds, the variety of which gave me the means of distinguishing the sky, the earth, the sea and, generally, all the other bodies, from one another [...] I was conscious that these ideas were presented to my mind, without my consent being required, so that I could perceive no object, however much I wished to, if it were not present to the organ of one of my senses; and it was in no way in my power not to perceive it, when it was so present.”

In this passage, Descartes is giving the reasons for why he thinks he is justified in believing in the existence of the material world. As seen here, what is crucial for Descartes is the fact that we are subject to certain experiences (heat, cold, light) over which we have no control—that is to say, involuntary experiences. It is because we have these involuntary experiences that Descartes concludes that the causes of these sensations are outside ourselves. Therefore, there must be a world of external and material causes that brings about certain impressions we have of the world.

“[...] because the ideas I received through the senses were much more vivid, more express and even, in their own way, more distinct than any of those which I could form for myself by meditation, or which I found imprinted in my memory, it seemed that they could not proceed from my mind, but that they had, of necessity, been caused in me by some other objects. Having no knowledge of these objects [...] I could form no other conclusion than that these objects resembled the ideas which they caused.”

In this passage, Descartes is restating his argument for the existence of material objects and the material world in general. According to Descartes, the reason we can be certain of the existence of the material world is due to the fact that we have involuntary experiences and sensations. Thus, the feeling of heat or cold is not something we can simply conjure and feel on command. Therefore, this involuntary characteristic of lived experience is proof for Descartes that the material world and its objects do indeed exist.