Keep silence for the most part, and speak only when you must, and then briefly.

Silence is the most perfect expression of scorn.

Always hungry, but never thirsty.

Just living is not enough... one must have sunshine, freedom, and a little flower.

Learn everything that is good from others, but bring it in, and in your own way absorb it; do not become others.

Liberty is the soul's right to breathe.

Science is the only basis of hope for human future.