olve representation of physical things, the argument proceeds in three distinct stages. (Med. VI) First, since the understanding conceives of extended things through its comprehension of geometrical form, it must at least be possible for things of this sort to exist. Second, since the imagination is directed exclusively toward the ideas of bodies and of the ways in which they might be purposefully altered, it is probable that there really are such things. Finally, since the faculty of sense perception is an entirely passive ability to receive ideas of physical objects produced in me by some external source outside my control, it is certain that such objects must truly exist. The only alternative explanation for perception, Descartes noted, is that god directly puts the ideas of bodies into my mind without there acutally being anything real that corresponds to them. (This is precisely the possibility that Malebranche would later accept as the correct account of the material world.) But Descartes supposed that a non-deceiving god would never maliciously give me so complete a set of ideas without also causing their natural objects to exist in fact. Hence, the bodies I perceive do really exist.Among the physical objects I perceive are the organic bodies of animals, other human beings, and myself. So it is finally appropriate to consider human nature as a whole: how am I, considered as a thinking thing, concerned with the organism I see in the mirror? What is the true relation between the mind and the body of any human being? According to Descartes, the two are utterly distinct. The Sixth Meditation contains two arguments in defence of Cartesian dualism: First, since the mind and the body can each be conceived clearly and distinctly apart from each other, it follows that god could cause either to exist independently of the other, and this satisfies the traditional criteria for a metaphysical real distinction. (Med. VI) Second, the essence of...
