"My propositions serve as elucidations in the following way: anyone who understands me eventually recognizes them as nonsensical, when he has used them—as steps—to climb up beyond them. (He must, so to speak, throw away the ladder after he has climbed up it.)" (6.54)

A central theme of the Tractatus is that we cannot talk about the nature of philosophy, the world, metaphysics, or anything "transcendental" without descending into nonsense. However, the propositions of the Tractatus deal with precisely these sorts of things, and on reflection, we realize that Wittgenstein could not have proscribed this kind of talk without descending into it himself. On the face of it, it would seem that his work is self-defeating. We must be careful to understand the purpose of the Tractatus, however: Wittgenstein is not trying to tell us a number of things that we did not already know; he is trying to instruct us in a way of thinking that will help us out of philosophical muddles. While the propositions of the Tractatus may themselves be nonsense, Wittgenstein hopes that they have served their instructive purpose. We are expected to put down this book not with a knowledge that the world is made up of objects and states of affairs and that propositions depict facts, but with an understanding of why it is impossible to say these sorts of things. The goal of the Tractatus, as Wittgenstein claims in his preface, is "to draw a limit … to the expression of thoughts."