 Presumably, Descartes’ point holds whether the doubt simply never occurs to him, or is instead prevented from occurring to him by a pill. But note that the objection is telling only insofar as the requisite indubitability is understood as merely psychological. Yet clear texts indicate that Descartes regards clear and distinct perception as having epistemic import beyond mere doubt-resistance. His use of light metaphors, including the association of clarity and distinctness with the natural light, strongly convey a form of rational insight. In his view, our inability to doubt the matters we clearly and distinctly perceive is not simply a causal result of our cognitive nature; it’s also a rational result of what such perception enables us to understand.