>And cannot an abstract have a physical existence with a very specific nature?
I suppose that is really what all of your questions above turn on. Well, let's think it through step by step and see what happens:
"Hmmm. Can I say that an abstraction can also be physical ie: concrete? If I did, I could take things we normally call "abstract" and simply say they have a *'very specific' type of physicality*. I could then draw a distinction as follows - say certain things - buses, rocks, the Eiffel Tower - are perhaps *physical* physicalities, and certain other things - ideas, free will, concepts - are *abstract* physicalities. Now, as a very important part of their "very specific nature", these 'abstract physicalities' also DO NOT have to obey the formulas of the laws of physics the way that *physical* physicalities like rocks or the Eiffel Tower do. I mean, the thought that a future physicist with the right formula could, in principle, predict every word I write in this post, and every other future thought in my head, just as they predict the movement of very distant stars to 1/500,000 of a mm obviously destroys the idea that I have any free will at all - a position clearly incompatible with Objectivism. So obviously this get-out clause from the usual laws of physics is essential. Excellent! Now with this special differentiation of 'abstract physicalities' and 'physical physicalities' firmly established, and the proper exclusions allowed for, I have now achieved the main aim, which is to preserve the word 'physical' in my system at all times. Now, when I debate the subject of determinism and free will with Daniel, I will remind him that he really should refer to "abstract physicalities" and 'physical physicalities' instead of just 'abstractions' and 'physicalities'."
Seriously: that is how it shakes out as far as I can see - a lot of heavy lifting to create a purely *verbal* distinction. In my view, this sort of thing doesn't really increase one's understanding of the actual problem one iota, it just adds a layer of confusion. However, as I don't argue over terms, I am happy to adopt this kind of usage and declare that consciousness is an *abstract physicality*, in sharp distinction a *physical physicality*, or "physicality 1" and 'physicality 2', or however *you'd* like to describe it.
And if *this* is physicalism, then I happily declare that I AM NOW A PHYSICALIST! Problem solved!
> Not all physical entities have the same physical properties. These vary widely. Many are yet unknown. So why on earth make up something like "non-physical"?
I certainly didn't "make up" the idea that something can be non-physical. It is what the word 'abstract' means! Do you disagree?
1. Considered apart from concrete existence: an abstract concept.