The mother is the child's supreme parent.

Every man of genius sees the world at a different angle from his fellows, and there is his tragedy.

The greatest task before civilization at present is to make machines what they ought to be, the slaves, instead of the masters of men.

Sexual pleasure, wisely used and not abused, may prove the stimulus and liberator of our finest and most exalted activities.

For every fresh stage in our lives we need a fresh education, and there is no stage for which so little educational preparation is made as that which follows the reproductive period.

Still, whether we like it or not, the task of speeding up the decrease of the human population becomes increasingly urgent.

It is only the great men who are truly obscene. If they had not dared to be obscene, they could never have dared to be great.