What we know is not capable of being otherwise; of things capable of being otherwise we do not know, when they have passed outsideour observation, whether they exist or not. Therefore the object of knowledge is of necessity. Therefore it is eternal; for things that are of necessity in the unqualified sense are all eternal; and things that are eternal are ungenerated and imperishable.

A friend is a second self, so that our consciousness of a friend's existence...makes us more fully conscious of our own existence.

Tragedy is an imitation not of men but of a life, an action

If men think that a ruler is religious and has a reverence for the Gods, they are less afraid of suffering injustice at his hands.

Education is the best provision for old age.

Youth should be kept strangers to all that is bad, and especially to things which suggest vice or hate. When the five years have passed away, during the two following years they must look on at the pursuits which they are hereafter to learn. There are two periods of life with reference to which education has to be divided, from seven to the age of puberty, and onwards to the age of one and twenty.

We should venture on the study of every kind of animal without distaste; for each and all will reveal to us something natural and something beautiful.