Man will never be entirely willing to give up this world for the next nor the next world for this.

The greatest obstacle to progress is not man's inherited pugnacity, but his incorrigible tendency to parasitism.

They who will live for others shall have great troubles, but they shall seem to them small. Those who will live for themselves shall have small troubles, but they shall seem to them great.

Man, as we know him, is a poor creature; he is halfway between an ape and a god and he is travelling in the right direction.

The great discovery of the nineteenth century, that we are of one blood with the lower animals, has created new ethical obligations which have not yet penetrated the public conscience. The clerical profession has been lamentably remiss in preaching this obvious duty.

A man may build himself a throne of bayonets, but he cannot sit on it.

Philosophy means thinking things out for oneself. Ultimately, there can be only one true philosophy, since reason is one and we all live in the same world.