Wittgenstein's Remarks on the Foundations of Mathematics was poorly received by the critics when it was first published, and only a few sympathetic commentators have made much of it since then. The book has not had a great success, because the majority of people interested in the philosophy of mathematics these days have a quite different approach to the subject from Wittgenstein. But not only that, they have a quite different logic from Wittgenstein. I believe one of the main sources of the antipathy felt towards the Remarks lies in the foreignness of the logic Wittgenstein develops there. I hope, in what follows, to make that logic more understandable, and with it the philosophy of mathematics it supports.