Sextus Empiricus offers an underappreciated and under-discussed version of dream-based skepticism. Most philosophers interested in dreams and skepticism focus on the question of how you know you are not currently dreaming. Sextus points out that our waking experiences and dreams often conflict. And, the challenge goes, what reason do you have to trust the one over the other? This question presupposes that dreams and waking experiences are distinguishable. Thus the kinds of responses typically offered against dream-based skepticism do not apply. (...) And if we accept an idea upheld by one camp in the contemporary debate over the epistemology of disagreement, Sextus’ challenge is difficult to answer. A G.E. Moore-inspired response to the problem is also proposed and explored. It is argued that Sextus’ version of the problem reveals a certain limitation in that sort of approach to skeptical problems. (shrink)