When you have thrown a stone, you cannot afterwards bring it back again, but nevertheless you are responsible for having taken up the stone and flung it, for the origin of the act was within you. Similarly the unjust and profligate might at the outset have avoided becoming so, and therefore they are so voluntarily, although when they have become unjust and profligate it is no longer open to them not to be so.

In general, what is written must be easy to read and easy to speak; which is the same.

Virtue is the golden mean between two vices, the one of excess and the other of deficiency.

A great city is not to be confounded with a populous one.

...The entire preoccupation of the physicist is with things that contain within themselves a principle of movement and rest.

Youth is easily deceived because it is quick to hope.

Excellence is never an accident. It is always the result of high intention, sincere effort, and intelligent execution; it represents the wise choice of many alternatives - choice, not chance, determines your destiny.