Abstract

Some philosophers think that a person can justifi ably believe that p is possible even though she has no theory according to which p is possible. They think, for example, that she can justifiably believe that there could be naturally purple elephants even though she lacks (inter alia) a theory about the factors germane to elephant pigmentation. There is a certain optimism about this view: it seems to assume that people are fairly good at ferreting out problems with proposed modal claims; so, if a person doesn’t detect one, then she’s within her rights to assume that there is no problem to be found. I am suspicious of this optimism, but I do not have space to challenge it here. Instead, I want to outline the more pessimistic alternative. Suppose that a person is not justified in believing that p is possible unless she has a theory according to which p is possible. How might such an account be developed? My aim is to map out this neglected option.