Our possibilities of happiness are already restricted by our constitution. Unhappiness is much less difficult to experience. We are threatened with suffering from three directions: from our own body, which is doomed to decay and dissolution and which cannot even do without pain and anxiety as warning signals; from the external world, which may rage against us with overwhelming and merciless forces of destruction; and finally from our relations to other men. The suffering which comes from this last source is perhaps more painful to us than any other.

Whatever fosters the growth of civilization works at the same time against war.

Just as no one can be forced into belief, so no one can be forced into unbelief.

The more the fruits of knowledge become accessible to men, the more widespread is the decline of religious belief.

The impression forces itself upon one that men measure by false standards, that everyone seeks power, success, riches for himself, and admires others who attain them, while undervaluing the truly precious thing in life.

The reproaches against science for not having yet solved the problems of the universe are exaggerated in an unjust and malicious manner; it has truly not had time enough yet for these great achievements. Science is very young--a human activity which developed late.

An intimate friend and a hated enemy have always been indispensable requirements for my emotional life; I have always been able to create them anew, and not infrequently my childish ideal has been so closely approached that friend and enemy coincided in the same person.