People live for the morrow, because the day-after-to-morrow is doubtful.

Loneliness is one thing, solitude another.

I will believe in the Redeemer when the Christians look a little more redeemed.

If Islam despises Christianity, it has a thousandfold right to do so: Islam at least assumes that it is dealing with men.

Does not the discipline of the scientific spirit just commence when one no longer harbours any conviction?

What then is truth? A movable host of metaphors, metonymies, and anthropomorphisms: in short, a sum of human relations which have been poetically and rhetorically intensified, transferred, and embellished, and which, after long usage, seem to a people to be fixed, canonical, and binding. Truths are illusions which we have forgotten are illusions — they are metaphors that have become worn out and have been drained of sensuous force.

Whereas the man of action binds his life to reason and its concepts so that he will not be swept away and lost, the scientific investigator builds his hut right next to the tower of science so that he will be able to work on it and to find shelter for himself beneath those bulwarks which presently exist.