By far the most striking feature of Wittgenstein’s moral or ethical thought is his insistence, in various places in his early philosophy, that there can be no such thing. There can be no ethical propositions for the early Wittgenstein, and therefore no ethical thoughts too. Instead, ethics is, in his view, transcendental. This chapter aims to do three things: first, to explain why there can be no ethical propositions for the early Wittgenstein (and so why ethics is, in his view, both inexpressible and unthinkable); second, to explain what the early Wittgenstein’s alternative vision of the ethical consists in (and so what he means in describing ethics as transcendental); and third, to explain what happens both to the claim that there can be no ethical propositions and to the accompanying vision of ethics in Wittgenstein’s later work, where they seem, to many, simply to drop out of the picture. Overall, this chapter aims to show what is both original and important about Wittgenstein’s moral or ethical thought, and so why it deserves to be taken seriously, in spite of the outlandishness of his claims.