Heaven and earth are teaching materials, and the sun and moon are firelight.

Thought does not come when you want it to come, but it determines its own coming and going. ——Schopenhauer

I know nothing except the fact of my ignorance. ——Socrates

Water is the origin of all things, and all things ultimately return to water. ——Thales

To make all irrational things subject to oneself and to freely control all irrational things according to one's own inherent laws, this is the ultimate goal of man. ——Fichte