Morally, a philosopher who uses his professional competence for anything except a disinterested search for truth is guilty of a kind of treachery.

There are still many people in America who regard depressions as acts of God. I think Keynes proved that the responsibility for these occurrences does not rest with Providence.

Science has made unrestricted national sovereignty incompatible with human survival. The only possibilities are now world government or death.

Laughter is the most inexpensive and most effective wonder drug. Laughter is a universal medicine.

It will be said that the joy of mental adventure must be rare, that there are few who can appreciate it, and that ordinary education can take no account of so aristocratic a good. I do not believe this. The joy of mental adventure is far commoner in the young than in grown men and women. ...It is rare in later life because everything is done to kill it during education.

There is exactly the same degree of possibility and likelihood of the existence of the Christian God as there is of the existence of the Homeric god. I cannot prove that either the Christian god or the Homeric gods do not exist, but I do not think that their existence is an alternative that is sufficiently probable to be worth serious consideration.

In the revolt against idealism, the ambiguities of the word experience have been perceived, with the result that realists have more and more avoided the word.