The Real Cartesian Distinction: Revisiting the Mind-Body Paradox (Part 2)

The second application is the real distinction:“…I am a thinking thing. And although probably (or rather, as afterward I will say, certainly) I have a body, which is very closely conjoined to me, because nevertheless on the one hand I have a clear and distinct idea of myself, insofar as I am only a thinking thing, not extended, and on the other hand I have a distinct idea of body, in so far as it is only an extended thing, not thinking, it is certain that I am really distinct from my body, and can exist apart from it.”I will provide a provisional reading of this argument, which to me seems natural:

(1) If A can exist apart from B, and vice versa, A is really distinct from B, and B from A.

(2) Whatever I can clearly and distinctly understand can be brought about by God.

(3) If I clearly and distinctly understand A apart from B, and vice versa, then God can bring it about that A and B are apart.

(4) If God can bring about A and B apart, then A and B exist apart.

(5) I am clearly and distinctly able to understand A apart from B if there are attributes Y and X, where I understand Y to belong to A only and X to belong to B only.

(6) Where A is my mind and B is my body, thought extension satisfy the conditions and Y and X respectively.

(7) Hence I am really distinct from my body and can exist apart from it.


What, if anything, is wrong with this argument? Whatever may be the connection in Descartes’s mind between his inability to doubt his own existence while doubting the existence of body it is perhaps not sufficiently captured by his real distinction, we may say. But it appears that if the mind and body are separate, that one may indeed be more certain than the other, which Descartes take to be the mind. Another objection may be that Descartes shows that mind and body are possibly distinct—and would be distinct if God chose to separate them—not that they are distinct. But Descartes holds that two things are really distinct if it is possible that they exist in separation. Therefore distinctness does not entail separation. It seems the objections are difficult to come by, so the next thing to ask is how one recognizes clear and distinct perceptions.

The Sixth Meditation concludes Descartes’s argument by means of the senses for the existence of body. Sensory perceptions must either be created by the Meditator himself, by someone or something else, or by God. The Meditator can rule himself out since he is not aware of creating these perceptions, and they come upon him so forcefully and involuntarily that it would be inconceivable that he could be the creative force behind them. This is proof enough that sensory perceptions have some outside cause. He is naturally inclined to think his sensory perceptions are caused by things that resemble those perceptions. Since God is not a deceiver, he must not be fooling him in giving him this natural inclination. Therefore, he concludes, bodies must be something like what they seem to be.

The discussion of sensory perceptions as being “caused” by some outside source marks an important turning point. The mind is sharply distinguished from the world of bodies around it. The Meditator argues that mind and body have nothing in common, so they must be two totally distinct substances. We could point out that Clark Kent and Superman are very dissimilar and are yet the same thing, and so argue by analogy that mind and body might be two very different ways of looking at the same thing. However, even the primary attributes of mind and body are different. Body is essentially extended, whereas mind is non-extended and essentially thinking. Since the two are totally different, the Meditator concludes that he is only mind, and not body. This is a step beyond what is stated by the sum res cogitans in the Second Meditation, as there the Meditator asserts that he only knows that he is a thinking thing. Now he knows that he is only a thinking thing.

This sharp distinction between mind and body has profound implications. If sensory experience is in the mind and the bodies that cause our sensations are in the world, the question arises as to how the two can causally interact. What is the connection between mind and world? When the mind and the world are held as totally distinct, the mind is then conceived of as being trapped within the body, unable to know about the world except through a “causal interface” at the sensory surfaces.