"The secret of change is to focus all of your energy, not on fighting the old, but on building the new."

"Our youth now love luxury. They have bad manners, contempt for authority; they show disrespect for their elders and love chatter in place of exercise; they no longer rise when elders enter the room; they contradict their parents, chatter before company; gobble up their food and tyrannize their teachers."

"I cannot teach anybody anything. I can only make them think."

"The beginning of wisdom is the definition of terms."

"The greatest blessing granted to mankind come by way of madness, which is a divine gift."

"Wealth does not bring about excellence, but excellence makes wealth and everything else good for men, both individually and collectively."

"Is there not one true coin for which all things ought to exchange?- and that is wisdom; and only in exchange for this, and in company with this, is anything truly bought or sold, whether courage, temperance or justice. And is not all true virtue the companion of wisdom, no matter what fears or pleasures or other similar goods or evils may or may not attend her? But the virtue which is made up of these goods, when they are severed from wisdom and exchanged with one another, is a shadow of virtue only, nor is there any freedom or health or truth in her; but in the true exchange there is a purging away of all these things, and temperance, and justice, and courage, and wisdom herself, are a purgation of them."

"He who is unable to live in society, or who has no need because he is sufficient for himself, must be either a beast or a god."

"Envy is the ulcer of the soul."

"If all our misfortunes were laid in one common heap whence everyone must take an equal portion, most people would be content to take their own and depart."

"May the inward and outward man be as one."

"If a man comes to the door of poetry untouched by the madness of the Muses, believing that technique alone will make him a good poet, he and his sane compositions never reach perfection, but are utterly eclipsed by the performances of the inspired madman."

"Employ your time in improving yourself by other men's writings so that you shall come easily by what others have labored hard for."

"Is there not one true coin for which all things ought to exchange?- and that is wisdom; and only in exchange for this, and in company with this, is anything truly bought or sold, whether courage, temperance or justice. And is not all true virtue the companion of wisdom, no matter what fears or pleasures or other similar goods or evils may or may not attend her? But the virtue which is made up of these goods, when they are severed from wisdom and exchanged with one another, is a shadow of virtue only, nor is there any freedom or health or truth in her; but in the true exchange there is a purging away of all these things, and temperance, and justice, and courage, and wisdom herself, are a purgation of them."

"He who is not contended with what he has would not be contended with what he would like to have."

"Nobody is qualified to become a statesman who is entirely ignorant of the problem of wheat."

"I desire only to know the truth and to live as well as I can... And, to the utmost of my power, I exhort all other men to do the same... I exhort you also to take part in the great combat, which is the combat of life, and greater than every other earthly conflict."

"An unconsidered life is not one worth living."

"Is there anyone to whom you entrust a greater number of serious matters than your wife? And is there anyone with whom you have fewer conversations?"

"To be is to do."