There was never a genius without a tincture of madness.
Aristotle (384 - 322 BC)
Contributed by: Zaady
Happiness depends upon ourselves.
Happiness is a state of activity.
Source: Politics
All human actions have one or more of these seven causes: Chance, nature, compulsions, habit, reason, passion, desire.
Source: Rhetoric 1
Humor is the only test of gravity, and gravity of humor; for a subject which will not bear raillery is suspicious, and a jest which will not bear serious examination is false wit.
Those that know, do. Those that understand, teach.
I have gained this from philosophy: that I do without being commanded what others do only from fear of the law.
Source: Diogenes Laeritius, Lives of Eminent Philosophers, book V
It is the mark of an educated mind to be able to entertain a thought without accepting it.
In educating the young we steer them by the rudders of pleasure and pain
Source: Nichomachean Ethics, Book X
The educated differ from the uneducated as much as the living from the dead.