The Real Cartesian Distinction: Revisiting the Mind-Body Paradox (Part 1)

The ‘real distinction’ argument has its roots in arguments developed in the Second Meditation concerning knowledge of the self as a thinking thing, and knowledge of the body as something “extended, flexible, movable.” Having used the Evil Genius hypothesis in the First Meditation to bring into doubt the existence of the body, Descartes argues in the Second Meditation that this doubt does not extend to his own existence (if he deceives Descartes, Descartes exists.) He then considers what attributes with certainty to himself at this stage of his reasoning. He concludes that even certain properties, like nutrition, must be excluded as part of the doubt of body. There is only one, he finds, that is not called into question on this basis: “I am therefore, strictly only a thinking thing.”

This seems to imply that Descartes has established his argument: that he is nothing but a thinking thing, and as such distinct from anything physical: “thought alone cannot be separated from me.” But Descartes does not wish to claim on the basis of the Second Meditation reasoning alone that he knows that he is only thought and there is nothing corporeal or physical about him. He is implicitly claiming to know, not merely that he thinks, but that thought pertains to his nature or essence: it “cannot be separated from me.” Also, he maintains that reasoning concerning the indubitability of his own existence has brought him to the conclusion that he is a “truly existing thing.”

The Second Meditation contains at least one other assertion that is important to the ‘real distinction’ argument: that Descartes has a clear and distinct idea of himself as a thinking thing. He begins to hint at this point immediately after the statements already cited. And at the end of the Second Meditation, after arguing that his best knowledge of a typical physical object—a piece of wax—is derived from reason rather than sense, he concludes that his existence is more distinct and evidence than that of the wax. The claims about distinct perception are important because of Descartes’s very consciously held position that only clear and distinct perceptions or conceptions will suffice as the basis for positive affirmations about the nature of a thing.

Between the Second and Sixth Meditations Descartes validates his distinct perceptions by setting forth “proofs” of the existence of an omnipotent and benevolent creator who would not permit Descartes to be deceived in what is most evident. Descartes is, then, so far from concluding rashly from what he can conceive to what is the case, that he finds it necessary to present God as a bridge from what he can distinctly conceive to what is the case.

We may now turn to the ‘real distinction’ argument itself. The Sixth Meditation begins with the observation that God is capable of bringing about or making the case whatever I am capable of clearly and distinctly perceiving: “…And I never judged that anything could not be brought about by him, except for the reason that it was impossible for me to perceive it distinctly.” The first application of this principle is to establish the possible existence of “physical things conceived as the object of mathematics”—since previous Meditations have held these to be distinctly conceivable.