The brightest flashes in the world of thought are incomplete until they have been proved to have their counterparts in the world of fact.

The mind of man may be compared to a musical instrument with a certain range of notes, beyond which in both directions we have an infinitude of silence.

It is as fatal as it is cowardly to blink facts because they are not to our taste.

Life is a wave, which in no two consecutive moments of its existence is composed of the same particles.