As then being is not one in all that we have just mentioned, so neither is good; nor is there one science either of being or of the good; not even things named good in the same category are the objects of a single science, eg opportunity or moderation; but one science studies one kind of opportunity or moderation, and another another: eg opportunity and moderation in regard to food are studied by medicine and gymnastics, in military matters by the art of strategy, and similarly with other sorts of action, so that it can hardly be the province of one science to study the good per se.