Doubt and certainty › The Cogito: The First Certainty

The Second Meditation begins with Descartes still in the grip of doubt. But now he presses the question: is there anything at all that I can know with certainty? He considers whether he himself exists. But if there is a deceiver, doesn't the deceiver's deception prove that Descartes exists? You cannot deceive something that does not exist. The very act of doubting, of being deceived, presupposes a doubter who is being deceived. > "I am, I exist, is necessarily true each time it is expressed by me, or conceived in my mind." > **The Cogito** > > Often rendered as "I think, therefore I am" (*cogito ergo sum*), this is Descartes' first certainty. The statement "I exist" cannot be doubted because the very act of doubting confirms the existence of the doubter. Even if I am being deceived about everything else, I cannot be deceived about the fact that I exist while being deceived. Descartes presents this as an immediate recognition rather than a syllogism from a general premise: thinking makes his existence evident to him. Every time I think, doubt, imagine, or perceive, I must exist to have those thoughts, even if their contents are false. But what am I, this thing that thinks? Descartes cannot assume he has a body, since the body might be an illusion created by the evil demon. What he cannot doubt is that he is a thinking thing: a thing that doubts, understands, affirms, denies, wills, refuses, imagines, and perceives. Even if his perceptions are illusory, the fact that he has perceptions is certain. At this stage, Descartes knows himself as a thinking thing while the existence of his body remains in doubt. That difference in what he knows does not by itself prove that mind and body are separate substances. He reserves the argument for their real distinction for the Sixth Meditation, after his arguments about God and clear and distinct understanding. The Second Meditation includes a famous thought experiment about a piece of wax. Descartes considers a piece of wax fresh from the honeycomb: it has a particular color, shape, size, smell, and texture. But when he brings it near the fire, all these sensory qualities change. The color, shape, size, smell, and texture are completely different. Yet we say it is the same wax. What is it that persists through this change? Not any sensory quality, since all of them changed. What persists is something that the mind grasps through understanding rather than through the senses: the wax is something extended, flexible, and changeable. In this example, a particular sensory appearance does not exhaust what Descartes understands the wax to be.