  A different tack is pursued by Williamson, who argues at length that we should not accept the idea that one has the same evidence in the good case and the bad case. Central to his argument is the contention that, even if one were to adopt the phenomenal conception of evidence, this would not allow one to vindicate the underlying intuitions that seemed to make its adoption attractive in the first place; hence, the phenomenal conception of evidence is ultimately not well-motivated. As we have seen, it is the desire to preserve the intuition that a sufficiently scrupulous thinker in the bad case can be reasonable in his beliefs (indeed, no less reasonable than a similarly scrupulous thinker in the good case) which seems to rule out any conception of evidence according to which one's evidence might consist of (say) true propositions or facts about the external world. For a thinker in the bad case is not in a position to recognize facts about the external world; he is, however, in a position to recognize facts about his own experiences. The view that one's evidence is limited to one's experiences thus seems to be motivated by the idea that one's evidence, no matter what else is true of it, must be the sort of thing that one is always in a position to correctly take into account, at least in principle. But (it is claimed) one's experiences are the things that one is always in a position to correctly take into account. Williamson argues that this last thought is a mistake: in fact, one is not always in a position to correctly take into account one's experiences, even in principle. Indeed, Williamson argues that there is no non-trivial condition which is such that one is always in a position to know that it obtains.  Thus, the thought that evidence might be such that one is always in a position to know what one's evidence is is a chimerical one. To insist that in order for x to be among one's evidence, x must be such that one is always in a position to know whether one's evidence includes x is thus to impose a misguided and unrealizable desideratum on the theory of evidence. In short: ‘Whatever evidence is, one is not always in a position to know what one has of it’ (2000: 178, emphasis added).