Error is multiform (for evil is a form of the unlimited, as in the old Pythagorean imagery, and good of the limited), whereas success is possible in one way only (which is why it is easy to fail and difficult to succeed - easy to miss the target and difficult to hit it); so this is another reason why excess and deficiency are a mark of vice, and observance of the mean a mark of virtue: Goodness is simple, badness is manifold.
We are what we repeatedly do... excellence, therefore, isn't just an act, but a habit and life isn't just a series of events, but an ongoing process of self-definition.
The so-called Pythagoreans, who were the first to take up mathematics, not only advanced this subject, but saturated with it, they fancied that the principles of mathematics were the principles of all things.
Of means of persuading by speaking there are three species: some consist in the character of the speaker; others in the disposing the hearer a certain way; others in the thing itself which is said, by reason of its proving, or appearing to prove the point.
Since we think we understand when we know the explanation, and there are four types of explanation (one, what it is to be a thing; one, that if certain things hold it is necessary that this does; another, what initiated the change; and fourth, the aim), all these are proved through the middle term.
For just as for a flute-player, a sculptor, or an artist, and, in general, for all things that have a function or activity, the good and the well is thought to reside in the function, so would it seem to be for man, if he has a function.
The line has magnitude in one way, the plane in two ways, and the solid in three ways, and beyond these there is no other magnitude because the three are all.