Learning acquired in youth arrests the evil of old age; and if you understand that old age has wisdom for its food, you will so conduct yourself in youth that your old age will not lack for nourishment.

Intellectual passion dries out sensuality.

A bird is an instrument working according to mathematical law, which instrument it is within the capacity of man to reproduce with all its movements.

If you throw a stone in a pond... the waves which strike against the shores are thrown back towards the spot where the stone struck; and on meeting other waves they never intercept each other's course... In a small pond one and the same stroke gives birth to many motions of advance and recoil.

My body is not a tomb for animals.

I say that the power of vision extends through the visual rays to the surface of non-transparent bodies, while the power possessed by these bodies extends to the power of vision.

Whatever you do in life, if you want to be creative and intelligent, and develop your brain, you must do everything with the awareness that everything, in some way, connects to everything else.