The sense of the world must lie outside the world... What we cannot speak about we must remain silent about... What can be described can happen too, and what is excluded by the laws of causality cannot be described.

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

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

Philosophy hasn't made any progress? - If somebody scratches the spot where he has an itch, do we have to see some progress? Isn't genuine scratching otherwise, or genuine itching itching? And can't this reaction to an irritation continue in the same way for a long time before a cure for the itching is discovered?

One cannot guess how a word functions. One has to look at its use and learn from that. But the difficulty is to remove the prejudice which stands in the way of doing this. It is not a stupid prejudice.

One can mistrust one's own senses, but not one's own belief.

Philosophy can be said to consist of three activities: to see the commonsense answer, to get yourself so deeply into the problem that the common sense answer is unbearable, and to get from that situation back to the commonsense answer.