Chapter 6

Descartes' teaching that thinking is essential to the human being

286. Here we can also say something in favour of Descartes. When he said, 'I think, therefore I am', he glimpsed a truth. The human soul in fact always thinks, because it has an immanent perception. Descartes deduced that the soul had always to think because the concept of human being is rooted in thinking, or rather, because thought is present in the concept of the human being. He should have spoken 1. about immanent thought, not transient acts of thought; these would prove only the existence of a subject who was as transient as the acts themselves; 2. about human thought, the kind that characterises humans and could not be the intuition of being, cut off from any nexus with the body; 3. about thought proper to the human subject, composed of soul and body. Immanent thought of this kind is simply the primal perception, the root of the nexus between the rational soul and the body. He sensed the truth therefore but did not grasp it, nor find the words to explain it.

287. Hence, when Romagnosi and others substituted Descartes' reasoning with 'I feel, therefore I am', they did not understand the possible force of their formula. Indeed 'I feel, therefore I am' does not in any way prove the existence of the human being; at most, it proves the existence of a sensitive being. To prove the existence of the human being we must have recourse to an act proper to a being composed of intelligence and animality, that is, to an act of the rational principle. Existence of such a being requires proof that his essence is subsistent, which means recourse to immanent thought because essence does not change. Explained in this way, Descartes' statement acquires light, and his reasoning, force; it proves that the essence of the human being lies in an immanent act of thought, but does not say which thought! It certainly cannot be any kind of thought; it must be the kind I described and called primal, natural perception.