The paper discusses Colin McGinn’s mysterianist approach to the phenomenon of consciousness. According to McGinn, consciousness is, in and of itself, a fully natural phenomenon, but we humans are just cognitively closed to it, meaning that we cannot in principle understand its nature. I argue that, on a proper conception of the relation between an intellectual problem and its solution, we may well not know what the solution is to a problem we understand, or we may not understand exactly what the problem is, but it is incoherent to suppose that we cannot understand what would count as a solution to a problem we can and do understand. The argument appeals to certain accepted assumption in the logic of questions, developed in the early sixties, mainly by Stahl. I close with a general characterization of mysterianism as such, and formulate a form of mysterianism which is in some sense more optimistic and in another more pessimistic than McGinn’s.