Not only does every animal live at the expense of some other animal or plant, but the very plants are at war.... The individuals of a species are like the crew of a foundered ship, and none but good swimmers have a chance of reaching the land.

History warns us that it is the customary fate of new truths to begin as heresies and to end as superstitions.

All knowledge is good. It is impossible to say any fragment of knowledge, however insignificant or remote from one's ordinary pursuits, may not some day be turned to account.

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.

Friendship involves many things but, above all the power of going outside oneself and appreciating what is noble and loving in another.

True science and true religion are twin sisters, and the separation of either from the other is sure to prove the death of both. Science prospers exactly in proportion as it is religious; and religion flourishes in exact proportion to the scientific depth and firmness of its basis.

All truth, in the long run, is only common sense clarified.