The practical effect of a belief is the real test of its soundness.

Science rests on reason and experiment, and can meet an opponent with calmness; but a belief is always sensitive.

You cannot dream yourself into a character; you must hammer and forge yourself one.

Age does not make us childish, as some say; it finds us true children.

A person possessed with an idea cannot be reasoned with.

Philosophy goes no further than probabilities, and in every assertion keeps a doubt in reserve.