The problem of dream skepticism is one of the most familiar in philosophy: the problem of how we can ever know that we are awake and not asleep and dreaming. I offer a partial solution to the problem: a solution which depends on certain background commitments and which is not applicable to all mental states (though it is applicable to many). I will suggest that, if my argument is successful, it may also open up a path for dealing with external world skepticism more generally.