The tyrant, who in order to hold his power, suppresses every superiority, does away with good men, forbids education and light, controls every movement of the citizens and, keeping them under a perpetual servitude, wants them to grow accustomed to baseness and cowardice, has his spies everywhere to listen to what is said in the meetings, and spreads dissension and calumny among the citizens and impoverishes them, is obliged to make war in order to keep his subjects occupied and impose on them permanent need of a chief.

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

In a democracy the poor will have more power than the rich, because there are more of them, and the will of the majority is supreme.

Knowledge of the fact differs from knowledge of the reason for the fact.

There is no great genius without a mixture of madness.

Happiness is the reward of virtue.

Those who assert that the mathematical sciences say nothing of the beautiful or the good are in error. For these sciences say and prove a great deal about them; if they do not expressly mention them, but prove attributes which are their results or definitions, it is not true that they tell us nothing about them. The chief forms of beauty are order and symmetry and definiteness, which the mathematical sciences demonstrate in a special degree.