Propositions show what they say: tautologies and contradictions show that they say nothing.

In order to draw a limit to thinking, we should have to think both sides of this limit.

A tautology's truth is certain, a proposition's possible, a contradiction's impossible.

The fact that we can describe the motions of the world using Newtonian mechanics tell us nothing about the world. The fact that we do, does tell us something about the world.

Logic must look after itself. In a certain sense, we cannot make mistakes in logic.

Someone who knows too much finds it hard not to lie.

And to imagine a language means to imagine a form of life.