The happy life is thought to be one of excellence; now an excellent life requires exertion, and does not consist in amusement.

...The entire preoccupation of the physicist is with things that contain within themselves a principle of movement and rest.

It is just that we should be grateful, not only to those with whose views we may agree, but also to those who have expressed more superficial views; for these also contributed something, by developing before us the powers of thought.

The same ideas, one must believe, recur in men's minds not once or twice but again and again.

...for all men do their acts with a view to achieving something which is, in their view, a good.

If one way be better than another, that you may be sure is nature's way.

No one loves the man whom he fears.