"Logic is not a body of doctrine, but a mirror-image of the world. Logic is transcendental." — Ludwig Wittgenstein

A nothing will serve just as well as a something about which nothing could be said.

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

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

A philosophical problem has the form: I don't know my way about.