There is a passage in the Nicomachean Ethics (NE) that holds out the promise of giving us a profound insight into Aristotle’s view of the good. The problem is that the passage, A.6: 1096a23-29, has proved remarkably resistant to satisfactory interpretation, defying the efforts of scholars over the last eight decades. It argues, contra Plato, that the good cannot be one thing and, according to Irwin’s translation, reads as follows:
Further, good is spoken of in as many ways as being is spoken of. For it is spoken of in [the category of] what-it-is, as god and mind; in quality, as the virtues; in quantity, as the measured amount; in relative, as the useful; in time, as the opportune moment; in place, as the [right] situation; and so on. Hence it is clear that the good cannot be some common [nature of good things] that is universal and single; for if it were, it would be spoken of in only one of the categories, not in them all.
Just what is Aristotle saying here? The main problem seems to lie in understanding what the relationship is between the good, or “good,” and the examples given: Just how are they related such that “good” turns out to be spoken of in as many ways as “being”— or, as some would put it, to have as many senses as “being”? Are they things of which “good” is predicated? Or is each itself a good which is predicated of something else? Or are they neither subjects nor predicates of sentences in which “good” occurs? If not, what is the connection between “good” and the examples?
Brakas, Jurgis, "MacDonald on Aristotle on the Good" (1997). The Society for Ancient Greek Philosophy Newsletter. 289.