 This passage is usually cited for the point that it makes about memory, but the picture that Descartes is here outlining is also one in which attention has an important epistemic role to play: clarity and distinctness realize their epistemic potential only when attention is being paid to the ideas that have them. Those ideas can be doubted, as, in accordance with the policy of the First Meditation they must be, but that doubt cannot be maintained by a properly attentive thinker. The crucial first move in Descartes’ epistemology—the move from radical doubt to certainty about the truth of particular clear and distinct ideas—is, therefore, a transition that is mediated by attention.