All propositions are of equal value.

If in life we are surrounded by death, so too in the health of our intellect by madness.

Mathematics is a logical method. . . . Mathematical propositions express no thoughts. In life it is never a mathematical proposition which we need, but we use mathematical propositions only in order to infer from propositions which do not belong to mathematics to others which equally do not belong to mathematics.

For an answer which cannot be expressed the question too cannot be expressed. The riddle does not exist. If a question can be put at all, then it can also be answered.

The philosophical I is not the human being, not the human body or the human soul with the psychological properties, but the metaphysical subject, the boundary (not a part) of the world.

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

A picture held us captive. And we could not get outside it, for it lay in our language and language seemed to repeat it to us inexorably.