The wise man is he who knows the relative value of things.

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.

Over-population is a phenomenon connected with the survival of the unfit, and it is a mechanism which has created conditions favourable to the survival of the unfit and the elimination of the fit.

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.

To become a popular religion, it is only necessary for a superstition to enslave a philosophy.

Literature flourishes best when it is half a trade and half an art.

There is no limit to the noble aspirations which the words "my country" may evoke.