I will never be an old man. To me, old age is always 15 years older than I am.

Travel, in the younger sort, is a part of education; in the elder, a part of experience.

In mathematics I can report no deficiency, except it be that men do not sufficiently understand the excellent use of Pure Mathematics.

Discretion in speech is more than eloquence.

But I account the use that a man should seek of the publishing of his own writings before his death, to be but an untimely anticipation of that which is proper to follow a man, and not to go along with him.

Men on their side must force themselves for a while to lay their notions by and begin to familiarize themselves with facts.

Ipsa scientia potestas est. (Knowledge itself is power.)