A man has no reason to be ashamed of having an ape for his grandfather. If there were an ancestor whom I should feel shame in recalling it would rather be a man who plunges into scientific questions with which he has no real acquaintance, only to obscure them by an aimless rhetoric.

Science is organized common sense where many a beautiful theory was killed by an ugly fact.

The quarrels of theologians and philosophers have not been about religion, but about philosophy; and philosophers not unfrequently seem to entertain the same feeling toward theologians that sportsmen cherish toward poachers.

Irrationally held truths may be more harmful than reasoned errors.

There are savages without God in any proper sense of the word, but none without ghosts.

A world of facts lies outside and beyond the world of words.

All truth, in the long run, is only common sense clarified.