Psychological Doubt and the Cartesian Circle

Abstract

Suppose that in the Meditations Descartes thinks he needs to prove that his clear and distinct perceptions are true. There can be little doubt that if he does think he needs to do this, he thinks that the way to do it is to prove that ‘a non-deceiving God exists’ is true. Now suppose that Descartes does come up with such a proof. Presumably he clearly and distinctly perceives both the premisses and that ‘a non-deceiving God exists’ follows from them. But that will not suffice to prove that ‘a non-deceiving God exists’ is true. For, if there is a problem about whether clear and distinct perceptions are true, then in advance of settling it, there is a problem about whether what is proved merely on the basis of clear and distinct perceptions is true.