Let no-one ignorant of geometry enter. Said to have been inscribed above the door of Plato's Academy.

For neither does wealth bring honour to the owner, if he be a coward; of such a one the wealth belongs to another, and not to himself. Nor does beauty and strength of body, when dwelling in a base and cowardly man, appear comely, but the reverse of comely, making the possessor more conspicuous, and manifesting forth his cowardice.

The Earth is like one of those balls made of twelve pieces of skin.

What the expression is intended to mean, I think, is that there is a better and a worse element in the character of each individual, and that when the naturally better element controls the worse then the man is said to be "master of himself", as a term of praise. But when - as a result of bad upbringing or bad company one s better element is overpowered by the numerical superiority of one s worse impulses, then one is criticized for not being master of oneself and for lack of self control.

The one who learns and learns and doesn't practice is like the one who plows and plows and never plants.

A state arises,as I conceive,out of the needs of mankind;no one is self-sufficing,but all of us have many wants

Tyranny naturally arises out of democracy.