“Are aggregates real?”
It depends on what you mean by real and what you mean by aggregate.
Here are two definitions of “real”:
OntologicallyReal – the idea that our model directly describes the substance of reality. For example, if “heaps of sand” are ontologically real, then that means- then that means that, in the Cosmic Computer of All Existance, there’s a few bytes that say, “Oh, there is a heap of sand over there,”.
Stable – the idea works as an abstraction, that is stable for a period of time, given certain parameters, and so on.
Atoms may not be “real,” because they can be taken apart: They are electrons, protons, neutrons, …
But those arrangements of electrons, protons, and neutrons, are stable enough, that we call them “real,” and just treat them as aggregate clumps.
Further, the atoms can combine into molecules. Molecules usually have shorter lifetimes, but they are stable enough, to get the designation: “Real.”
So “Real” and “Stable” are connected words.
I believe most of us would accept that atoms are probably not ontologically real. When an atom is split apart, the universe doesn’t switch representations from, “Oh, there was an atom there, but now I’m going to replace it with a bunch of electrons, protons, and neutrons, and some radiation.”
This was inspired by conclusions from “AreGroupsReal.”
Most of us will probably agree that aggregates are not ontologically real.
But I think that most of us will agree that most aggregates we care to talk about (AreGroupsReal, AreConversationsReal) are stable enough, to persist, to be worthy of note, and even to build other aggregates out of.