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.
In the world of knowledge, the essential Form of Good is the limit of our inquiries, and can barely be perceived; but, when perceived, we cannot help concluding that it is in every case the source of all that is bright and beautiful -in the visible world giving birth to light and its master, and in the intellectual world dispensing, immediately and with full authority, truth and reason -and that whosoever would act wisely, either in private or in public, must set this Form of Good before his eyes.
I would believe any religion that could prove it had existed since the beginning of the world. But when I see Socrates, Plato, Moses, and Mohammed I do not think there is such a one. All religions owe their origin to man.
Those who intend on becoming great should love neither themselves or their own things, but only what is just, whether it happens to be done by themselves or others.
We ought to esteem it of the greatest importance that the fictions which children first hear should be adapted in the most perfect manner to the promotion of virtue.
For the introduction of a new kind of music must be shunned as imperiling the whole state; since styles of music are never disturbed without affecting the most important political institutions.
[Aristotle] was the most eminent of all the pupils of Plato.... He seceded from Plato while he was still alive; so that they tell a story that [Plato] said, " Aristotle has kicked us off, just as chickens do their mother after they have been hatched.