Philosophy is like trying to open a safe with a combination lock: each little adjustment of the dials seems to achieve nothing, only when everything is in place does the door open.

One can defend common sense against the attacks of philosophers only by solving their puzzles, i.e., by curing them of the temptation to attack common sense.

I am still at Trattenbach, surrounded, as ever, by odiousness and baseness. I know that human beings on the average are not worth much anywhere, but here they are much more good-for-nothing and irresponsible than elsewhere.

It is one of the chief skills of the philosopher not to occupy himself with questions which do not concern him.

It would strike me as ridiculous to want to doubt the existence of Napoleon; but if someone doubted the existence of the earth 150years ago, perhaps I should be more willing to listen, for now he is doubting our whole system of evidence.

My attitude towards him is an attitude towards a soul. I am not of the opinion that he has a soul. . . .

That which cannot be said must not be said. That which cannot be said, one must be silent thereof.