I wrote this for my introduction to philosophy class.
According to dualism, the mind can exist separately of the body and is not dependent upon the body to exist. The body is a physical entity that exists wholly in the material world. The mind, though, is analogous to the soul or the conscious and, unlike eating or breathing, is not considered a function of the physical form.
Descartes’ believed that our idea of perfection, which he assumed does not exist in the real world, could not have come from experience. In what I believe to be a confounding leap of judgment, he uses this ides to justify the existence of a perfect being, namely God. Like the empiricist, Descartes acknowledged the error implicit in our senses. However, Descartes did not believe that a perfect God would deceive humanity. Moreover, he used the existence of a perfect God to justify the position that our senses are at least reliable enough and that they are a function of the physical body.
Descartes’ basic premise is that if two things are not identical in every possible way, then they are not identical. As an example, consider two identical stoned whose compositions are identical down to the very last atom. Their positions in space would still differ and they would thus not be completely identical. Descartes’ argument from doubt is flawed, in my opinion. He correctly claims that he can not doubt his own mind exist even though he can doubt everything else, including his body. In other words, his mind and body have differing properties and can thus be distinguished from one another. However, Descartes goes on further to claim that said discernible qualities imply that the mind and body can exist separately. Suppose, hypothetically, that the conscious is an emergent property of the body. The mind would still be beyond all doubt, and it would still be discernible from the body, but it would be unable to exist without it. Though hypothetical, it simply shows that multiple conditions can still satisfy the premise Descartes uses in his argument from doubt. This means Descartes’ conclusion that the mind and body can exist completely separate is a non sequitur because numerous other assumptions are at least equally compatible. That the mind and body are discernible only implies that they differ in at least one quality, but it does not imply that they differ in all qualities.
Water, in bulk, has differing properties from molecular water. A single molecule of water is not wet, nor is it a good solvent. Only by combining more than a single molecule do emergent properties like wetness or surface tension begin to appear. If Descartes’ argument is sound, it would imply that if molecular water ceased to exist wetness would not cease to be. An emergent property, however discernible, is still dependent on something.