This is essential reading for all students of Wittgenstein, and for those studying epistemology and philosophy of language. Wittgenstein's final work, addresses a category of "world-picture" propositions discovered by G.E. Moore. These challenge Wittgenstein's enduring commitment to a well-defined category of empirical propositions, and help to generate a critique of scepticism. Developing Wittgenstein's view that scepticism is self-undermining, the offers a combative yet therapeutic interpretation that locates between the standpoints of Kant and Hume.