Whereof one cannot speak, thereof one must be silent. — Ludwig Wittgenstein

If I cannot say a priori what elementary propositions there are, then the attempt to do so must lead to obvious nonsense.

A tautology's truth is certain, a 's possible, a contradiction's impossible. (Certain, possible, impossible: here we have the first indication of the scale that we need in the theory of probability.)

The world and life are one.