The ideas gained by men before they are twenty-five are practically the only ideas they shall have in their lives.

The greatest empiricists among us are only empiricists on reflection: when left to their instincts, they dogmatize like infallible popes.

Individuality is founded in feeling

Everyone knows that on any given day there are energies slumbering in him which the incitement's of that day do not call forth. Compared with what we ought to be, we are only half awake. The human individual usually lives far within his limits.

We must be careful not to confuse data with the abstractions we use to analyse them.

There is nothing so absurd that it cannot be believed as truth if repeated often enough.

In the matter of belief, we are all extreme conservatives.