If you do not rest on the good foundation of nature, you will labour with little honor and less profit.

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.

O time! swift devourer of all created things!

Everything comes from everything, and everything is made out of everything, and everything returns into everything.

Those who are enamoured of practice without science are like a pilot who goes into a ship without rudder or compass and never has any certainty of where he is going. Practice should always be based upon a sound knowledge of theory.

Oysters open completely when the moon is full; and when the crab sees one it throws a piece of stone or seaweed into it and the oyster cannot close again so that it serves the crab for meat. Such is the fate of him who opens his mouth too much and thereby puts himself at the mercy of the listener.

I have been impressed with the urgency of doing. Knowing is not enough; we must apply. Being willing is not enough; we must do.