Virtue is a state of war, and to live in it we have always to combat with ourselves.

He who has the base necessities of life should pay nothing; taxation on him who has a surplus may, if need be; extend to everything beyond necessities.

Remorse sleeps during a prosperous period but wakes up in adversity.

The world of reality has its limits; the world of imagination is boundless.

The abuse of books kills science. Believing that we know what we have read, we believe that we can dispense with learning it.

Women, in general, are not attracted to art at all, nor knowledge, and not at all to genius.

Teach your scholar to observe the phenomena of nature; you will soon rouse his curiosity, but if you would have it grow, do not be in too great a hurry to satisfy this curiosity. Put the problems before him and let him solve them himself. Let him know nothing because you have told him, but because he has learnt it for himself. Let him not be taught science, let him discover it. If ever you substitute authority for reason he will cease to reason; he will be a mere plaything of other people's thoughts.