The scientific imagination always restrains itself within the limits of probability.

I am too much of a sceptic to deny the possibility of anything...

My fundamental axiom of speculative philosophy is that materialism and spiritualism are opposite poles of the same absurdity-the absurdity of imagining that we know anything about either spirit or matter.

Every living creature commences its existence under a form different from, and simpler than, that which it eventually attains.

The foundation of all morality is to have done, once and for all, with lying; to give up pretending to believe that for which there is no evidence, and repeating unintelligible propositions about things beyond the possibilities of knowledge.

Only one absolute certainty is possible to man, namely that at any given moment the feeling which he has exists.

The Bible account of the creation of Eve is a preposterous fable.