The Frankfurt cases debunked the principle of alternate possibilities as necessary for free will. I suggest reading my other comment where I go into further details: https://news.ycombinator.com/item?id=19928438
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.
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.
This is exactly why free will evaporates. Your decision making apparatus and the factors that go into your choice are a given. Multiply yourself and the situation by a million, you will always make the same decision using the same apparatus and the same factors, unless there is a random element, but that is random, not free. You're not constrained, but you are, at a very basic level, determined.