As regards the number of ways in which a term is used, we must not only treat of those terms which are used in different ways, but we must also try to render their definitions; eg we must not merely say that justice and courage are called good in one way, and that what conduces to vigour and what conduces to health are called so in another, but also that the former are so called because of a certain intrinsic quality they themselves have, the latter because they are productive of a certain result and not because of any intrinsic quality in themselves.