Full Idea
Things are called good in as many senses as they are said to exist (e.g. substance, quality, quantity, relation, place, time); clearly, then, there cannot be a single universal common to all cases.
Gist of Idea
Each category of existence has its own good, so one Good cannot unite them
Source
Aristotle (Nicomachean Ethics [c.334 BCE], 1096a23)
Book Reference
Aristotle: 'Ethics (Nicomachean)', ed/tr. ThomsonJ A K/TredennickH [Penguin 1976], p.70
A Reaction
It doesn't follow that because you can divide the substratum, that therefore the superstructure lacks unity. One tree has many roots. We must ask whether a good substance and a good quantity have anything in common.