And when you cannot prove that people are wrong, but only that they are absurd, the best course is to let them alone.

Irrationally held truths may be more harmful than reasoned errors.

Every philosophical thinker hails it [The Origin of Species] as a veritable Whitworth gun in the armoury of liberalism.

It may be well to remember that the highest level of moral aspiration recorded in history was reached by a few ancient Jews--Micah, Isaiah, and the rest--who took no count whatever of what might not happen to them after death. It is not obvious to me why the same point should not by and by be reached by the Gentiles.

I would rather be the offspring of two apes than be a man and afraid to face the truth.

The mathematician starts with a few propositions, the proof of which is so obvious that they are called self-evident, and the rest of his work consists of subtle deductions from them. The teaching of languages, at any rate as ordinarily practiced, is of the same general nature authority and tradition furnish the data, and the mental operations are deductive.

Common sense is science exactly in so far as it fulfills the ideal of common sense; that is, sees facts as they are, or at any rate, without the distortion of prejudice, and reasons from them in accordance with the dictates of sound judgment. And science is simply common sense at its best, that is, rigidly accurate in observation, and merciless to fallacy in logic.