A friend's only gift is himself.

You cannot prove realism to a complete sceptic or idealist; but you can show an honest man that he is not a complete sceptic or idealist, but a realist at heart. So long as he is alive his sincere philosophy must fulfil the assumptions of his life and not destroy him.

Knowledge of what is possible is the beginning of happiness.

A soul is but the last bubble of a long fermentation in the world.

There is nothing sacred about convention; there is nothing sacred about primitive passions or whims; but the fact that a convention exists indicates that a way of living has been devised capable of maintaining itself.

To be boosted by an illusion is not to live better than to live in harmony with the truth ... these refusals to part with a decayed illusion are really an infection to the mind.

The diseases which destroy a man are no less natural than the instincts which preserve him.