To think that you are not following a rule is to follow a rule.

Believers who have formulated such proofs [for God's existence] ... would never have come to believe as a result of such proofs

We could present spatially an atomic fact which contradicted the laws of physics, but not one which contradicted the laws of geometry.

If you tried to doubt everything you would not get as far as doubting anything. The game of doubting itself presupposes certainty.

Almost in the same way as earlier physicists are said to have found suddenly that they had too little mathematical understanding to be able to master physics; we may say that young people today are suddenly in the position that ordinary common sense no longer suffices to meet the strange demands life makes. Everything has become so intricate that for its mastery an exceptional degree of understanding is required. For it is not enough any longer to be able to play the game well; but the question is again and again: what sort of game is to be played now anyway?

For life in the present there is no death. Death is not an event in life. It is not a fact in the world.

Everything that can be thought at all can be thought clearly. Everything that can be said can be said clearly. Ludwig Wittgenstein