It's not obvious to me where your other comment addresses my thought experiment.

The Frankfurt cases addresses your thought experiment. My comment fills in the blanks of how we can define free will without relying on the principle of alternate possibilities which the Frankfurt cases debunked (and also explains the difference between the various conceptions of "free will" that typically cause this confusion).

A lot of this is about moral philosophy, which doesn't interest me. I'm more interested in causality. But I don't see why determinism would mean you can't be held morally responsible, or "free will" would be necessary for morality to work. Sunni Muslims don't believe in free will, and certainly believe in moral responsibility.

> A lot of this is about moral philosophy, which doesn't interest me

That's what the free will debate in philosophy is about: whether there's a coherent conception of free volition that can justify holding an actor morally responsible for their choices.

The philosophical question is the context of "free will" discussed by the article. Other notions of free will may or may not overlap, as I described in my other comment.

> Sunni Muslims don't believe in free will, and certainly believe in moral responsibility.

Interesting claim, but from what I've just read they do believe in free will, but they also believe that God knows all outcomes, ie. determinism/predestination. In other words, they are Compatibilists.

>That's what the free will debate in philosophy is about: whether there's a coherent conception of free volition that can justify holding an actor morally responsible for their choices.

Well, I don't care about that question. I'm interested in whether free will exists as a matter of [meta]physics, prior to questions of morality.