If ... we state the function of man to be a certain kind of life, and this to be an activity or actions of the soul implying a rational principle, and the function of a good man to be the good and noble performance of these, and if any action is well performed when it is performed in accordance with the appropriate excellence ... human good turns out to be activity of the soul in accordance with virtue, and if there are more than one virtue, in accordance with the best and most complete

Aristotle
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