Abstract

The question of what Descartes did and did not doubt in the Meditations has received a significant amount of scholarly attention in recent years. The process of doubt in Meditation I gives one the impression of a rather extreme form of skepticism, while the responses Descartes offers in the Objections and Replies make it clear that there is in fact a whole background of presuppositions that are never doubted, including many that are never even entertained as possible candidates of doubt. This paper resolves the question of this undoubted background of rationality by taking seriously Descartes’ claim that he is carrying out demonstrations modeled after the great geometers. The rational order of geometrical demonstration demands that we first clear away previous demonstrations not proven with the certainty necessary for genuine science. This is accomplished by the method of doubt, which is only applied to the results of possible demonstrations. What cannot be doubted are the very concepts and principles employed in carrying out geometrical demonstration, which enable it to take place. It would be senseless to ask whether we can doubt the essential components of the structure through which questioning, doubting, and demonstration are made possible.