Aristotle, Eudemian Ethics

We must consider, therefore, what the best is, and in how many senses the term is used. The answer seems to be principally contained in three views. For it is said that the best of all things is the Absolute Good, and that the Absolute Good is that which has the attributes of being the first of goods and of being by its presence the cause to the other goods of their being good; and both of these attributes, it is said, belong to the Form¹ of good (I mean both being the first of goods and being by its presence the cause to the other goods of their being good), since it is of that Form that goodness is most truly predicated (inasmuch as the other goods are good by participation in and resemblance to the Form of good) and also it is the first of goods, for the destruction of that which is participated in involves the destruction of the things participating in the Form (which get their designation by participating in it), and that is the relation existing between what is primary and what is subsequent; so that the Form of good is the Absolute Good, inasmuch as the Form of good is separable from the things that participate in it, as are the other Forms also.

Now a thorough examination of this opinion belongs to another course of study, and one that for the most part necessarily lies more in the field of Logic, for that is the only science dealing with arguments that are at the same time destructive and general. But if we are to speak about it concisely, [20] we say that in the first place to assert the existence of a Form not only of good but of anything else is an expression of logic and a mere abstraction (but this has been considered in various ways both in extraneous discourses² and in those on philosophical lines); next, even granting that Forms and the Form of good exist in the fullest sense, surely this is of no practical value for the good life or for conduct.

For 'good' has many senses, in fact as many as 'being.' For the term 'is,' as it has been analyzed in other works, signifies now substance, now quality, now quantity, now time, and in addition to these meanings it consists now in undergoing change and now in causing it; and the good is found in each of these cases³—in essence, as mind and God, in quality justice, in quantity moderation, in time opportunity, and as instances of change, the teacher and the taught. Therefore, just as being is not some one thing in respect of the categories mentioned, so neither is the good, and there is no one science either of the real or of the good. But also even the goods predicated in the same category, for example opportunity or moderation, do not fall within the province of a single science to study, but different sorts of opportunity and of moderation are studied by different sciences, for instance opportunity and moderation in respect of food are studied by medicine and gymnastics, in respect of military operations by strategics, and similarly in respect of another pursuit by another science; so that it can hardly be the case that the Absolute Good is the subject of only one science.