In Aristotelian terms, is the "good" of Socrates a secondary substance (a universal) or, in Parmenides's terms, is it a being?
Which definition (interpretation) of the Socratic "good" describes it best?
I would guess that Socrates' definition of the good would be more like "being" than a secondary substance. However, I also think it would exceed the limits of "being"; to me, it seems like Socrates' definition of the good would have been something that could also become an attribution of process. On plato.stanford.edu, Aristotle is supposed to have thought that the definition of the good is particular to the object you are describing, so "the good" is not stable in its definition (https://plato.stanford.edu/entries/aristotle/#EssHom). I do not think Socrates would have subscribed to this version of defining goodness. Parmenides seems to have defined being as something completely stable; what is, can be known by definition (https://plato.stanford.edu/entries/presocratics/#ParEle). I think Socrates would have defined the good as something that really is, in a stable way - but would not necessarily have connected this with its automatic know-ability. Rather, perhaps Socrates would have connected the know-ability of goodness with adherence to a sincere process of inquiry. One of Socrates' target I think was men believing they had privileged access to a definition of virtue, and yet because they would not adhere to a sincere process of inquiry, they necessarily missed out on understanding the nature of goodness, as it is independently of men's vanity