Tyrants preserve themselves by sowing fear and mistrust among the citizens by means of spies, by distracting them with foreign wars, by eliminating men of spirit who might lead a revolution, by humbling the people, and making them incapable of decisive action.

Young men have strong passions and tend to gratify them indiscriminately. Of the bodily desires, it is the sexual by which they are most swayed and in which they show absence of control...They are changeable and fickle in their desires which are violent while they last, but quickly over: their impulses are keen but not deep rooted.

Intuition is the source of scientific knowledge.

Happiness does not consist in pastimes and amusements but in virtuous activities.

We give up leisure in order that we may have leisure, just as we go to war in order that we may have peace.

The roots of education are bitter, but the fruit is sweet.

Excellence is not an art. It is the habit of practice.