As you cannot do what you want, Want what you can do

Not to anticipate is already to moan.

It vexes me greatly that having to earn my living has forced me to interrupt the work and to attend to small matters.

Here is a thing which the more it is needed the more it is rejected: and this is advice, which is unwillingly heeded by those who most need it, that is to say, by the ignorant.

Patience serves as a protection against wrongs as clothes do against cold.

Many will think they may reasonably blame me by alleging that my proofs are opposed to the authority of certain men held in the highest reverence by their inexperienced judgments; not considering that my works are the issue of pure and simple experience.

All our knowledge originates in opinion.