The whole is more than the sum of its parts.

The vigorous are no better than the lazy during one half of life, for all men are alike when asleep.

I will not allow the Athenians to sin twice against philosophy.

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.

It was through the feeling of wonder that men now and at first began to philosophize.

The soul is the cause or source of the living body. The terms cause and source have many senses. But the soul is the cause of its body alike in all three senses which we explicitly recognize. It is (a) the source or origin of movement, it is (b) the end, it is (c) the essence of the whole living body.

The soul is characterized by these capacities; self-nutrition, sensation, thinking, and movement.