This, in turn, calls into question her basic rationality, if not in general, then at least with respect to this corner of human life. Wittgenstein puts the matter this way in On Certainty:154. There are cases such that, if someone gives signs of doubts where we do not doubt, we cannot confidently understand his signs as signs of doubt. I.e., if we are to understand his signs of doubt as such, he may give them in particular cases and may not give them in others.