Darkness is absence of light. Shadow is diminution of light.

All our knowledge originates in opinion.

A man was desired to rise from bed because the sun was already up. He replied: "If I had as far to go and as much to do as he has, I should be up by now; but having but a little way to go, I shall not get up yet."

Being engulfed in practice without delicate knowledge related to it, is in many ways like entering a ship without knowing where it is headed.

... we might say that the earth has a spirit of growth; that its flesh is the soil, its bones the arrangement and connection of the rocks of which the mountains are composed, its cartilage the tufa, and its blood the springs of water.

Savage is he who saves himself.

To such an extent does nature delight and abound in variety that among her trees there is not one plant to be found which is exactly like another; and not only among the plants, but among the boughs, the leaves and the fruits, you will not find one which is exactly similar to another.