A thing chosen always as an end and never as a means we call absolutely final. Now happiness above all else appears to be absolutely final in this sense, since we always choose it for its own sake and never as a means to something else.
AristotleFor nature by the same cause, provided it remain in the same condition, always produces the same effect, so that either coming-to-be or passing-away will always result.
AristotleThere are, then, these three means of effecting persuasion. The man who is to be in command of them must, it is clear, be able (1) to reason logically, (2) to understand human character and goodness in their various forms, and (3) to understand the emotions--that is, to name them and describe them, to know their causes and the way in which they are excited.
Aristotle