 In the Second Set of Objections, Mersenne poses the following problem: although Descartes has argued that our ability to know anything depends on our first knowing that God exists and is not a deceiver, it seems clear that an atheist mathematician can have the same sort of mathematical knowledge as a theist. In response, Descartes allows that the atheist does have a clear awareness (cognitio) of simple mathematical truths, but he denies that this clear awareness is “true knowledge [scientia]” (PW 2, p. 101). At first glance, it seems that Descartes draws the distinction between cognitio and scientia precisely so he can deny certainty to the atheist mathematician. But there is good reason to think that this is not what he has in mind.