> These differences are - obviously, I might add - very important. And they have nothing to do with magical free will.
So why continue to use an unrelated term that has so much baggage? Why not just tackle these issues individually, on their own terms, in language that isn't laundering outmoded intuitions about some magic grounds for responsibility?
Because they _do_ have something to do with _actual_ free will. When you drill down at what "free will" could plausibly and coherently mean, you inevitably end up focusing on these important differences.
And then you can _actually_ begin to articulate why someone is culpable and another person isn't. A magical free will believer can't really make sense of that, because if free will is something indescribable and magic, there is no reason to believe a person does not have free will to do X, just because they e.g. are incapable of doing it.
Conversely, if you believe _both_ in magical free will, and have also thought about the material conditions for free will (e.g. they must be informed, and understand the consequences, and not be coerced etc.), then you already have a completely coherent materialistic belief about free will, and have just awkwardly bolted supernaturalness to its side, completely unnecessarily.
Because they _do_ have something to do with _actual_ free will.
But this is the problem right there, you call it actual free will and someone believing in magical free will will deny this and call magical free will actual free will. Sure, one can do this, overload the term, and figure out from context what kind of actual free will is meant in each instance. But would it not be much easier to give up on the term free will and use new different terms for different things?
It's similar to how both people who believe in phlogiston and people who believe in chemistry call fire "fire" - or how people who believe in the life spark and people who don't call life "life", or how people call light "light" regardless of whether they believe in the ether, the standard model or something else.
No matter the academic discussion of what free will is or isn't, we still have to address the fact that dominoes and animals and people appear to behave according to different rules. We have to consider the difference between freedom and coercion. We have to address what accountability and responsibility means, and what makes a person morally blameworthy.
This is what people talk about when they talk about free will. That's why people can claim they strongly believe in free will without being able to articulate, or even having thought much about, how free will is instantiated.
In short: Because "free will" is a name for something we concretely observe. We may be misinterpreting what we observe (maybe it _is_ an illusion), but we still only have that one name for that thing.
> the fact that dominoes and animals and people appear to behave according to different rules
The crux of the issue is that you're wrong here. Humans have this vanity that we're special, but we're really not. We behave according to the same rules, we're just relatively complex systems within those rules compared to dominoes.
When most people think of "free will", what they actually mean is "unpredictability". That's why nobody thinks dominoes have free will, some people think animals have free will, and lots of people think humans have free will. It's much harder to predict human behavior from the point of view of a human than dominoes, but to a superintelligent AI, we're just dominoes.
> accountability and responsibility ... morally blameworthy.
It's actually very simple and doesn't require any such notions. If there is a thing that is causing you or others harm, you act to prevent that thing from causing harm. There's no difference between a murderer and a deadly snake in that regard. I'm not going to ponder whether or not its morally blameworthy as I remove it from my house.
Not sure what you mean by that. If you're looking for a rigorous mathematical proof that humans obey the same laws of physics as everything else, I can't offer you one. However, the burden of proof is on someone asserting that humans are somehow special. I'll believe it when I see it.
In a theoretical vacuum, maybe. However we've done a fair amount of exploring ourselves and the way we work, and we haven't found a soul yet. Asserting that humans are somehow special requires explaining the lack of any supporting evidence.
This is a variant of the god-of-the-gaps argument, which is not turning out well for proponents of religion, as those gaps keep getting smaller and smaller. Again, I'll believe it when I see it.
So why continue to use an unrelated term that has so much baggage? Why not just tackle these issues individually, on their own terms, in language that isn't laundering outmoded intuitions about some magic grounds for responsibility?