Free Will vs. Quantum Indeterminism

Many scientists are determinists; they don't believe in free will. I do. Not only that, but I believe it is impossible to consistently deny it. If your thoughts and beliefs are determined by outside forces, then so is your belief in determinism. How do you know you believe in determinism because it is true? The outside forces clearly force a lot of people to believe false ideas, and not only that, but it is the forces themselves that determine whether people will ever be permitted to uncover the falsity of these ideas -- if the forces say no, then too bad, you're stuck with the mistakes forever, and you will have no way to know! Is determinism one of these mistakes? You will never know. This is Ayn Rand's argument against determinism.

A belief in determinism is an epistemic virus that infects any other beliefs you might hold. It is a one-way ticket to radical skepticism and thus equally self-defeating.

It might seem tempting to retort that with the advent of quantum mechanics determinism isn't really on the table anymore. Bohr giveth just as Newton tooketh away, on this view. Here are some problems with it:

1. Quantum mechanics isn't really about indeterminism.

It is true that Bohr and his students were radical indeterminists. What is not so well known is that Bohr held this view prior to even the discovery of matrix mechanics or the Schrodinger equation, much less any kind of semi-coherent formulation of the Copenhagen interpretation. That indeterminism was grafted onto quantum theory was an historical accident due primarily to Bohr's pre-existing philosophical committments, in particular his thoroughgoing rejection of causality. Apart from that accident it seems likely that Louis de Broglie's discovery of what David Bohm later developed into a fully consistent, realist (and also deterministic) interpretation of quantum theory would have prevailed. (The question of how this determinism is circumscribed by man's volition would remain.)

2. Epistemic nature of probability.

There has never been any basis whatsoever to transform what had been the purely epistemic concept of probability into something whose referents are out there in the external world. This transformation requires a kind of conspiracy theory about the meaning of quantum mechanics. Laplace & co. come up with the nice concept of mathematical probability that at the time everyone concedes was purely epistemic, describing our lack of complete knowledge in a given context. Then quantum mechanics comes along and we discover this amazing new phenomenon in nature, and fortuitously the exact concept we need to describe it already exists, with the slight difference that previously the concept had just been referring to stuff in our heads. It's as if a new discovery in electrical engineering brings about a revolution in our understanding of nano-electronics if we just accept the proposition that currents exhibit the emotions of happiness and sadness.

The idea that such a semantic maneuver is permitted by the open-ended nature of concepts misses the point. The question is not whether one is permitted to include these new referents under the concept of probability, the question is what new facts could possibly give us a reason to include them. Paraphrasing John Bell, both the observer-created-reality and indeterministic aspects of quantum mechanics are the result of premeditated theoretical preference, and are not in any way necessitated by experimental discoveries. The whole QM101 attitude of having to transform one's basic philosophy only grudgingly in recognition of new data is an affectation and a canard. (Zeilinger and Wheeler are perhaps the loudest living advocates of this canard.)

3. The actual meaning of quantum indeterminism.

Let's suppose for a moment that quantum indeterminism were the basis of free will. What would this mean exactly? Because the indeterministic interpretations of quantum mechanics are all terribly vague. The seat of indeterminism is supposed to be the wavefunction collapse event. And what causes this event? The "observer," answers quantum indeterminism. So there is no real physical foundation for free will provided here, there is only a vague, misplaced reference to some sort of consciousness. Yes, consciousness is an axiomatic concept that, logically, is irreducible. It is not, however, a concept that belongs in the axioms of a theory of physics, unless you want to posit mind as a new physical substance. Do not however presume that quantum mechanics provides some new, technical, empirical justification for this maneuver. There is not a single experiment that reveals anything unique about the physical matter of the brain in this regard. There is only an old theoretical preference that can be dressed up in modern clothes, and smeared with some gaudy quantum lipstick.

But another kind of interpretation of quantum mechanics exists (Bohm's), one that explains every experimental result in terms of, and situates every mathematical formulation within, a conventional kind of physical account -- an account that does not vaguely posit some new substance (mind-icles) for which no evidence exists. Only a desire to instantiate premeditated metaphysical beliefs could motivate the rejection of such a theory in favor of quantum free will.

Where does this leave us? Free will exists. Quantum mechanics doesn't tell us anything about it. Looks probable that free will and the mind are emergent phenomena -- emerging from a sufficiently complicated brain. We have barely even begun to understand the brain enough to have a clue as to how this works.