Everything factual is, in a sense, theory. The blue of the sky exhibits the basic laws of chromatics. There is no sense in looking for something behind phenomena: they are theory.

Hypotheses are the scaffolds which are erected in front of a building and removedd when the building is completed. They are indispensable to the worker; but the worker must not mistake the scaffolding for the building.

Take care of your body with steadfast fidelity. The soul must see through these eyes alone, and if they are dim, the whole world is clouded.

Method will teach you to win time.

Such is the frailty of man that even where he makes the truest and most forcible impression in the memory, in the heart of his beloved, there also he must perish.

Only by joy and sorrow does a person know anything about themselves and their destiny. They learn what to do and what to avoid.

Association with women is the basis of good manners.