 Further issues about the cogito are worth clarifying – let’s cover a few points in summary fashion. First, a first-person formulation is essential to the certainty of the cogito. Third-person claims, such as “Icarus thinks,” or “Descartes thinks,” are not unshakably certain – not for me, at any rate; only the occurrence of my thought has a chance of resisting hyperbolic doubt. There are a number of passages in which Descartes refers to a third-person version of the cogito. But none of these occurs in the context of establishing the actual existence of a particular thinker (in contrast with the conditional, general result that whatever thinks exists).