Those who have a natural talent for calculation are generally quick-witted at every other kind of knowledge; and even the dull, if they have had an arithmetical training, although they may derive no other advantage from it, always become much quicker than they would have been.

Much sleep is not required by nature, either for our souls or bodies, or for the action in which they are concerned.

Enjoy life. There's plenty of time to be dead. Be kind, for everyone you meet is fighting a harder battle.

Wisest is he who knows what he does not know.

The science [geometry] is pursued for the sake of the knowledge of what eternally exists, and not of what comes for a moment into existence, and then perishes.

The beginning is the most important part...for that is the time character is being formed.

For the man who makes everything that leads to happiness, or near to it, to depend upon himself, and not upon other men, on whose good or evil actions his own doings are compelled to hinge,--such a one, I say, has adopted the very best plan for living happily. This is the man of moderation; this is the man of manly character and of wisdom.