"Ideas are the source of all things."

"Old age has a great sense of calm and freedom. When the passions have relaxed their hold and have escaped, not from one master, but from many."

"Nothing in the affairs of men is worthy of great anxiety."

"The man who makes everything that leads to happiness, depends upon himself, and not upon other men, has adopted the very best plan for living happily. This is the man of moderation, the man of manly character and of wisdom."

"Self-conquest is the greatest of victories."

"The like is not the friend of the like in as far as he is like; still the good may be the friend of the good in as far as he is good."

"Excellence of understanding comes from something divine, whereas the other excellences are probably close to the body."

"Philosophy is the highest music."

"It behooves those who take the young to task to leave them room for excuse, lest they drive them to be hardened by too much rebuke."

"You are young, my son, and, as the years go by, time will change and even reverse many of your present opinions. Refrain therefore awhile from setting yourself up as a judge of the highest matters."