I'm reading the Nicomachean Ethics written by Aristotle and there's this one statement (and it's motivations) that I'm really struggling with. In my version of the book it is written in rather proficient English and I'm having a hard time understanding what it says.
So, in chapter I (The Object of Life) under the 6th statement ("There cannot be a universal good such as Plato held to be in his theory of forms"), Aristotle writes this:
But things are called good both in the category of substance and in that of quality and in that of relation; and what exists in its own right, namely substance, is by nature prior to what is relative (for this is a sort of offshoot of attribute of that which exists); so that there cannot be any common idea in these cases.
I have read this over and over again and I can still not understand it. I don't have any knowledge of Plato's Theory of Forms, so that might be the reason, if Aristotle is referring to that. Aristotle then says:
Again, things are called good in as many senses as they are said to exists; for they are so called in the category of substance (e.g. god or mind) and in quality (the virtues) and in quantity (what is moderate) and in relation (what is useful) and in time (opportunity) and in place (habitat and so on).
This I understood better and it seems rather obvious, but I still cannot make up what the first sentence would mean.
What is that Aristotle means in the first sentence and how does he motivate that there is no universal good?