In the human mind, one-sidedness has always been the rule, and many-sidedness the exception. Hence, even in revolutions of opinion, one part of the truth usually sets while another rises.

It often happens that the universal belief of one age of mankind — a belief from which no one was, nor without an extraordinary effort of genius and courage, could at that time be free — becomes to a subsequent age so palpable an absurdity, that the only difficulty then is to imagine how such a thing can ever have appeared credible.

Hardly any original thoughts on mental or social subjects ever make their way among mankind or assume their proper importance in the minds even of their inventors, until aptly selected words or phrases have as it were nailed them down and held them fast.

Every great movement must experience three stages: ridicule, discussion, adoption.

Almost all rich veins of original and striking speculation have been opened by systematic half-thinkers.

The doctrine called Philosophical Necessity is simply this: that, given the motives which are present to an individual's mind, and given likewise the character and disposition of the individual, the manner in which he will act might be unerringly inferred: that if we knew the person thoroughly, and knew all the inducements which are acting upon him, we could foretell his conduct with as much certainty as we can predict any physical event.

It is a law, that every event depends on some law.