It is not what the man of science believes that distinguishes him, but how and why he believes it. His beliefs are tentative, not dogmatic; they are based on evidence, not on authority or intuition.

An Honest politician will not be tolerated by a democracy unless he is very stupid ... because only a very stupid man can honestly share the prejudices of more than half the nation.

Broadly speaking, we are in the middle of a race between human skill as a means and human folly as an end.

I believe that when I die I shall rot, and nothing of my ego will survive.

The significance of a fact is relative to [the general body of scientific] knowledge. To say that a fact is significant in science, is to say that it helps to establish or refute some general law; for science, though it starts from observation of the particular, is not concerned essentially with the particular, but with the general. A fact, in science, is not a mere fact, but an instance. In this the scientist differs from the artist, who, if he deigns to notice facts at all, is likely to notice them in all their particularity.

Power is sweet; it is a drug, the desire for which increases with a habit.

None but a coward dares to boast that he has never known fear.