In trying to make clear whether understanding is a mental state Wittgenstein asks a series of questions about the timing and duration of understanding. These questions are awkward, and they have posed a great challenge for commentators. In this paper I review the interpretations by Mole and by Baker and Hacker, and point out their problems. I then offer a new interpretation which shows (1) that a “mental state” in this context means a state of consciousness, (2) that Wittgenstein's questions (...) are intended to elicit the grammars of the words “understand” and a “state of consciousness”, (3) that, in this way, he clearly shows that understanding is not a state of consciousness and (4) that he also provides a therapy to dissolve the problem. (shrink)