He who knows that enough is enough will always have enough.

We must test our theories with the rigor of experiments.

Truth conquers slowly. There is a wondrous vitality in Error.

He who is not a good servant will not be a good master.

True knowledge exists in knowing that you know nothing.

You become what you believe, not what you think or what you want.

The small charity from the heart is better than the great charity from the head.