“If you find yourself in a hole, the first thing to do is stop digging.”

He that is giddy thinks the world turns round.

Who sows virtue reaps honour.

The purpose of learning is growth, and our minds, unlike our bodies, can continue growing as we continue to live.

Short words are best and the old words when short are best of all.

Facts are the air of scientists. Without them you never can fly.

Science, my lad, is made up of mistakes, but they are mistakes which it is useful to make, because they lead little by little to the truth.

Trusting our intuition often saves us from disaster.

We must not say every mistake is a foolish one.