We said above that what we should choose is neither too much nor too little, but “the mean,” and that “the mean” is what “right reason” prescribes. This we now have to explain.
Each of the virtues we have discussed implies (as every mental habit implies) some aim which the rational man keeps in view when he is regulating his efforts; in other words, there must be some standard for determining the several modes of moderation, which we say lie between excess and deficiency, and are in accordance with “right reason.” But though this is quite true, it is not sufficiently precise. In any kind of occupation which can be reduced to rational principles, it is quite true to say that we must brace ourselves up and relax ourselves neither too much nor too little, but “in moderation,” “as right reason orders;” but this alone would not tell one much; e.g. a man would hardly learn how to treat a case by being told to treat it as the art of medicine prescribes, and as one versed in that art would treat it.