Al-Khalili seems to be a compatibilist — that is, he seems to find physical determinism compatible with free will, though he sees quantum mechanics as throwing a wrench into the determinism. I agree: if we reran the tape of the universe, or even the tape of life, I think things would come out differently, for in the origins of the universe, and probably in the origins of new species, true quantum indeterminism plays a role. In the case of life, for instance, it may have a hand in the production of mutations, which are the very fuel of evolution.Coyne's argument is essentially that whether the laws of physics are deterministic, chaotic, or random, there cannot be free because all possibilities are contrary to free will.
But Al-Khalili, unlike some other compatibilists, doesn’t see quantum indeterminacy as rescuing free will. And I don’t think others, do, either—even if that indeterminacy plays out in our brains so that at any given moment we could equally well make either of two decisions. That kind of “quantum” free will is based on pure physical randomness and, to paraphrase Dan Dennett, “is not the kind of free will worth wanting.”
No, Al-Khalili finds free will elsewhere: in unpredictability. That is, our brains are incredibly intricate—they contain roughly ten billion nerve cells, each cell connected to others through about 10,000 synapses (cell-to-cell connections made via chemical or electrical stimuli) — so predicting how a series of environmental inputs will result in a given behavioral output — a decision — can often be impossible. ...
Chaos theory, of course, is deterministic: it’s a theory that simply says that very slight alterations in the initial conditions of a complex system (say, weather patterns) can lead to very different outcomes (whether you get a hurricane). It’s all deterministic, playing out through the non-quantum laws of physics. It’s just that, like the three-body problem, we don’t know enough to work out such systems from first principles.
What baffles me is how you can derive “free will”, if that term has any meaning, from unpredictability. Yes, we can’t predict our decisions, but they still are, according to Al-Khalili, determined by the laws of physics. How does that add up to “freedom” in any meaningful sense? His statement that the choices are “real” choices is ambiguous.
Ignoring his politics, philosophy, and theology, his physics is wrong. Quantum mechanics teaches that electrons have free will. Physics do not agree on the Interpretations of quantum mechanics, as different philosophies are possible. But there is certain no scientific evidence for ruling out free will.