The race of the guardians must be kept pure.

Arithmetic has a very great and elevating effect, compelling the soul to reason about abstract number, and rebelling against the introduction of visible or tngible objects into the argument.

For when there are no words, it is very difficult to recognize the meaning of the harmony and rhythm, or to see any worldly object is imitated by them.

Those who are not schooled and practised in truth [who are not honest and upright men] can never manage aright the government, nor yet can those who spend their lives as closet philosophers; because the former have no high purpose to guide their actions, while the latter keep aloof from public life.

Man's greatest victory is over oneself.

It was Plato, according to Sosigenes, who set this as a problem for those concerned with these things, through what suppositions of uniform and ordered movements the appearances concerning the movements of the wandering heavenly bodies could be preserved.

Happiness springs from doing good and helping others.