I think perhaps I need to go back to basics - and, as far as possible, try to avoid any thought experiments.
First point: by "free will", I mean that what I might call a "true" decision is capable of being made. I quite happily accept that we all appear to have what we call free will, and agree that when I pause for a moment to think of the mot juste, I present every sign of utilising that "free will" in my decision. There is no possible way for anyone - including myself - to predict what word I will choose, and so in general terms it is reasonable to infer that we do, indeed, have "free will".
That, if you like, is the practical definition. I'm not trying to argue that we all seem to be able to make choices, and that at any decision point in time, we fully feel as if we really COULD make any decision at all. Please bear that in mind for everything that follows.
That's not what I am arguing against. What I am arguing is that - to ME - when you call something "free will", it ACTUALLY means that you have the ability to make a decision. That in absolutely identical circumstances, we truly could make this decision, or that - AND, that it would indeed be a "decision", and not the result of randomn quantum events.
Randomness first: if a part - or, perhaps, ANY part - of the decision-making process is random, then I can't see how that can in any way be called "will". If my "decision" as to whether to turn left, or right, is ultimately governed by a (metaphorical) toss of a coin, then I can't dignify that with the word "will". If "free will", in the sense I am now discussing, comes from absolutely random events, then that - to me - is not will.
Causality second: its my understanding that the physical laws of the universe are fixed. That for a specific set of circumstances, there is one specific outcome. That outcome may be completely beyond our capability to predict, due to the vast number of variables that need to be considered, but will nonetheless produce the same result every time, in the same circumstances. If you do A, to B, where you can account for EVERYTHING about both A and B, you will ALWAYS (in a causal universe) get outcome C. In a completely causal universe, I can't see how "free will" is possible, with the emphasis on "free". If we accept that physical laws will yield identical results in identical circumstances (and I can't see how we can assert otherwise), then there is no "free will" that can exist. The universe would run from start to finish in exactly the same way every time, if we were able to wind it back and start again. And yes - that IS an untestable assertion, but I am, I believe, basing it on the logical conclusion that physical rules will always produce the same result - that 1+1 will always be 2.
Causality PLUS randomness - which I believe is how the universe actually IS - is also a non-starter for me when we are talking about "free will". Parts of this universe exclude "free", other parts exclude "will" - and, to my mind, the exclusion of each part individually does NOT mean that, when combined, free will suddenly becomes possible. I also do not intend to inder that - in a universe of THIS type - we would indeed see the same results every time on a "wind back and re-start" experiment: of course not, if there is GENUINE randomess in the model, then like the butterfly in China we would rapidly see the universe going off on a completely different tangent. I entirely accept that....BUT, that still does not, to me, grant that we have "free will".
It comes down, to me, to this. For a specific set of variables - by which I am talking about ALL variables in the universe, with all the history leading up to that point - an entirely causal universe can ONLY move to a single, specific next point, because every interaction will be governed by specific physical laws that accumulate to give particular results. Add randomness to the mix, however, and we will indeed see one specific set of variables produce two, ten, a billion, an infinite number of "next steps". THAT is indeed, the universe we live in (although clearly the quantum randomess must have very small impacts, else we'd see a lot more people spontaneously turning into banans!).
That's the universe we live in, a universe that by combination of causality and quantum gives the strong illusion that we are - somehow - able to make genuine "choices" and "decisions".
I get that - I really do. What I don't get - and which, I'm afraid, referring to concepts like emergent complexity don't answer for me - is how it can be asserted that a "person" is able at a particular point in time to (if you like) suppress the randomness, and overrule the causal elements, and be able to say about itself "there was nothing predetermined, and nothing random about the choice I just made. No physical laws governed what I just decided, I CHOSE. I operated my Free Will and made a decision that was not the inevitable result of what came before".
I honestly, genuinely, do NOT understand how "free will", in any manner worthy of the name, actually works.
It may well be that the explanation is out there, but I've not seen it. Or if I've seen it, I've not understood it. But my position can be "easily" (heh) altered: if emergent complexity IS the answer, it just needs to explain (in words I can understand, natch!), how increased complexity caused there to come a point where physical laws can produce two (or more) outcomes from a particular set of variables, without those outcomes being random.
Not "demonstrate", I'll grant that - neither my position, nor the alternate, is possible of being proven in a real-world experiment. But what I feel extremely strongly about is that my hypothesis works, and is both internally consistent, and consistent with what we know of the universe. I genuinely and honestly do not feel that any legitimate counter has been given to my hypothesis, in that in no case has it been explained where and how it is going wrong.
Jaime, you're right - I DO keep popping into these threads and making this point, and its for that exact reason! Nobody can show me the expereiment that proves me wrong, and that's not what I am after - all I want to change my mind is the clear explanation of where and how my logic breaks down. If I've missed that, I sincerely apologise, there's an awful lot of words on these topics and quite possible I missed it!
And sorry for the length! On the positive side, if you read this far (and believe in free will) you have no-one to blame but yourself! Feel sorry for me though - I had no choice but to type every single letter - typos and all!