Excess and Defect

In everything that is continuous and divisible it is possible to take more, less, or an equal amount, and that either in terms of the thing itself or relatively to us; and the equal is an intermediate between excess and defect.

By the intermediate in the object I mean that which is equidistant from each of the extremes, which is one and the same for all men; by the intermediate relatively to us that which is neither too much nor too little -- and this is not one, nor the same for all.

For instance, if ten is many and two is few, six is the intermediate, taken in terms of the object; for it exceeds and is exceeded by an equal amount; this is intermediate according to arithmetical proportion. But the intermediate relatively to us is not to be taken so; if ten pounds are too much for a particular person to eat and two too little, it does not follow that the trainer will order six pounds; for this also is perhaps too much for the person who is to take it, or too little -- too little for Milo, too much for the beginner in athletic exercises. The same is true of running and wrestling.

Thus a master of any art avoids excess and defect, but seeks the intermediate and chooses this -- the intermediate not in the object but relatively to us.

(c) Aristotle, Nicomachean Ethics, Book II, Chapter 6