Besides building up an argument from fundamental philosophical principles to prove the existence of God, Descartes’s other stated goal in the Meditations is to demonstrate that the human soul (or mind) exists and is distinct from the body. He does this by combining two arguments, one at the beginning of the book and one at the end. At the beginning, when he tries to doubt everything he possibly can, the Meditator argues that he can know one thing for certain: he definitely exists and is definitely thinking. This leads him to the conclusion that his essence is to be “a thinking thing”—a mind or soul. At the end of the book, the Meditator concludes that he can trust his clear and distinct perceptions of physical objects, which means he can say with certainty that his body is real, too. As he considers senses and sensations like sight, pain, and thirst, he argues that the mind and body are obviously connected, since the mind can control the body and bodily sensations can affect the mind. Descartes even speculates that the body and mind come into contact in a particular region of the brain (the pineal gland). Thus, in the Meditations, Descartes makes the case for the kind of mind-body distinction that he is famously associated with today, which is often called the “ghost in the machine”—he argues that humans are made of the fusion between an immaterial soul (a conscious, thinking essence that represents the true self) and a physical body (which is like a machine for the soul to control).
Descartes was by no means the first philosopher to argue that humans are made of a body and a mind, but his version of this dualism has arguably become the most influential—and the most controversial—in Western science and culture over the last several centuries. On the one hand, Descartes’s ideas have become an accepted foundation for contemporary math and science, which view themselves as disciplines in which minds study the physical world in the abstract to produce purely rational theories. On the other, contemporary philosophers and cognitive scientists frequently challenge the way Descartes presents the mind as superior to the body: he sees the mind as the true source of individual identity and humans’ distinctiveness as a species, and he presents the body as little more than a fleshy vessel for the mind to occupy.
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Mind and Body Quotes in Meditations on First Philosophy
As to the body, however, I had no doubts about it, but thought I knew its nature distinctly. If I had tried to describe the mental conception I had of it, I would have expressed it as follows: by a body I understand whatever has a determinable shape and a definable location and can occupy a space in such a way as to exclude any other body; it can be perceived by touch, sight, hearing, taste or smell, and can be moved in various ways, not by itself but by whatever else comes into contact with it. For, according to my judgement, the power of self-movement, like the power of sensation or of thought, was quite foreign to the nature of a body; indeed, it was a source of wonder to me that certain bodies were found to contain faculties of this kind.
Thinking? At last I have discovered it—thought; this alone is inseparable from me. I am, I exist—that is certain. But for how long? For as long as I am thinking. For it could be that were I totally to cease from thinking, I should totally cease to exist. At present I am not admitting anything except what is necessarily true. I am, then, in the strict sense only a thing that thinks; that is, I am a mind, or intelligence, or intellect, or reason—words whose meaning I have been ignorant of until now. But for all that I am a thing which is real and which truly exists. But what kind of a thing? As I have just said—a thinking thing.
But what then am I? A thing that thinks. What is that? A thing that doubts, understands, affirms, denies, is willing, is unwilling, and also imagines and has sensory perceptions.
The difference between this mode of thinking and pure understanding may simply be this: when the mind understands, it in some way turns towards itself and inspects one of the ideas which are within it; but when it imagines, it turns towards the body and looks at something in the body which conforms to an idea understood by the mind or perceived by the senses.
I know that everything which I clearly and distinctly understand is capable of being created by God so as to correspond exactly with my understanding of it. Hence the fact that I can clearly and distinctly understand one thing apart from another is enough to make me certain that the two things are distinct, since they are capable of being separated, at least by God. […] It is true that I may have […] a body that is very closely joined to me. But nevertheless, on the one hand I have a clear and distinct idea of myself, in so far as I am simply a thinking, non-extended thing; and on the other hand I have a distinct idea of body, in so far as this is simply an extended, non-thinking thing. And accordingly, it is certain that I am really distinct from my body, and can exist without it.
Indeed, there is no doubt that everything that I am taught by nature contains some truth. For if nature is considered in its general aspect, then I understand by the term nothing other than God himself, or the ordered system of created things established by God. And by my own nature in particular I understand nothing other than the totality of things bestowed on me by God.
In these cases and many others I see that I have been in the habit of misusing the order of nature. For the proper purpose of the sensory perceptions given me by nature is simply to inform the mind of what is beneficial or harmful for the composite of which the mind is a part; and to this extent they are sufficiently clear and distinct. But I misuse them by treating them as reliable touchstones for immediate judgements about the essential nature of the bodies located outside us; yet this is an area where they provide only very obscure information.
My final observation is that any given movement occurring in the part of the brain that immediately affects the mind produces just one corresponding sensation; and hence the best system that could be devised is that it should produce the one sensation which, of all possible sensations, is most especially and most frequently conducive to the preservation of the healthy man. And experience shows that the sensations which nature has given us are all of this kind; and so there is absolutely nothing to be found in them that does not bear witness to the power and goodness of God.
