Descartes assures himself of his own existence by his modes of thought, he remains uncertain of the reality of an external world. He doubts whether there is anything of material substance that provokes thought within him rather than it being conceived in his mind completely independent of anything else. Descartes then considers those reasons that have inclined him to believe these material things exist in the past. "I know by experience that these ideas do not depend upon my will, nor consequently upon myself, for often I notice them against my will... I feel heat, and therefore I believe that this feeling or idea of heat comes to me from something other than myself, namely from the fire I am near. Nothing is more obvious than the judgment that this object (rather than something else) grafts its likeness on to me." He disputes that he is a "rational animal" for this idea is difficult to understand. He scrutinizes whether perhaps he is a body infused with a soul but this idea is dismissed since he cannot be certain of concepts that are of the material world. Eventually he focuses on the act of thinking and from this he posits: "I am a thing that thinks" A thing that doubts, understands, affirms, denies, wills, refuses, and that also imagines and senses. To prove that perception on the part of the mind is more real than that of the senses Descartes asks us to consider a piece of wax. The mind takes up no space. It consists of the senses and all modes of thought. Matter, however, takes up space. It can be divided into smaller and smaller components, but it, unlike the mind, has no consciousness. Both, he infers have God as their source because God, alone, exists independent of anything else. But, the substances do not have any contact with each other. Thought is independent of matter just as matter is independent of thought. But, although the two are indeed completely independent of each other, there is constant interaction between the...
