 Still, some philosophers might object that the meditator has no business using principles that he does not know to be true. Descartes would not be sympathetic to this objection. As he says in his conversation with Burman, so long as the meditator is using the causal principles, “he is actually paying attention to them. And for as long as he does pay attention to them, he is certain that he is not being deceived, and he is compelled to give his assent to them” (PW 3, p. 334; see also PW 2, pp. 25, 48; see also Cottingham 1986, p. 67). So, the doubt that Descartes raises with respect to clear and distinct perceptions does not extend to the moments at which one is actually enjoying them. Rather, it is a doubt that, in general, clear and distinct perception may not be a reliable source of beliefs (Kenny 1968, p. 194). When Descartes introduces the evil demon hypothesis in the First Meditation, it is meant to encapsulate his ignorance of his own origin—and, in particular, ignorance of the construction of his own mind. Without knowing that a non-deceiving God exists, it is possible for the meditator that his mind works in such a way that it falls into error even when it is contemplating the simplest questions. This doubt is chased away when he actually does contemplate such a question, but it can easily return at a later time when his thoughts are turned elsewhere. This is the sense in which the atheist mathematician’s cognitio, or clear awareness, is imperfect. Although it is certain at the time the atheist has the perception, it can always be rendered doubtful at another time. The theist has no advantage over the atheist at the time each enjoys a clear and distinct perception. Rather, the theist’s advantage lies in the fact that, armed with the certainty that a non-deceiving God exists, she will always remain free from doubt (Descartes PW 2, p. 48; see also Kenny 1968, p. 193; Reed 2012). Consequently, she will be able to construct her scientific theories without ever falling prey to worries about whether her work has value, and—perhaps even more importantly—she will be in a position to definitively put an end to theoretical disagreements with others. (The Stoics make a similar distinction; see Cicero On Academic Scepticism, p. 84.)