Mental States as Justifiers Ciara Fairley University College London Davidson once claimed that the only thing that could justify a belief was another belief. That precludes one’s perceptual experiences playing a justifying role and that seems very implausible. But how much of a justifying role might they play? Can one’s perceptual experiences justify one’s perceptual beliefs all by themselves or is it only in conjunction with other beliefs that they can do so? In this paper I examine the most important argument in favour of the partially belief-based view, and argue that such a view leads to an unpalatable scepticism about perceptual knowledge. The argument is based on the fact that perceptual justification is defeasible, so I’ll show how we can make sense of that fact without supposing that perceptual justification is always partly belief based. I’ll defend a view on which the justification for one’s perceptual beliefs may be wholly non-beliefbased and show how that view defuses the sceptical threat.