Free will! Saint Augustine wrote about it linking our consciousness to a direct connection to the mind of God, and discussion about whether God left us, as evidenced by Adam and Eve and the apple, with free will. Then in the Abrahamic tradition, the question of free will is intimately tied up with the omnipotence of God and the conditions of forbearance in God's use of his Will in granting us humans our own free will.
The debate changed radically in the West with Rene' Descartes and Newton. Descartes famously proposed a dualism: Res Extensa and Res Cogitans. Res Extensa is a philosophical version of his "mechanistic" philosophy in which the bodies of humans, like all animals and plants and other things in the universe are "machines". But for humans, the mind is Res Cogitans, thinkiing "stuff".
For Descartes, as I have noted in previous blogs, this raised two major questions: 1) How could mind ACT on matter? 2) How could mind have a free will, which seems to be both an uncaused cause, yet a "choice" we make, perhaps via Res Cogitans.
Matters assumed their more or less modern form with stunning Newton, the differential and integral calculus, initial and boundary conditions and thus deterministic differential equations, ordinary and partial. Given the initial conditions and boundary conditions, the future (and past) behavior of the system is entirely determined. One integrates the differential equations. I keep being amazed at the degree to which we are captives of Newton's conceptual framework.
Given that framework, the first question for Descartes seems unaswerable: 1) How can mind act on matter? If we assume, as virtually all scientists do, that the mind and brain are "identical", then the brain's dynamics is some kind of deterministic system of differential equations, thereby a Cartesian machine. (I note again that recourse to "stochastic" differential equations does not remove the underlying determinism, but only makes US ignorant of the details of the perhaps chaotic or noisy behavior, which remains deterministic in detail.) Given this determinism, the brain is fully sufficient to determine the next state of the brain. Then, critically, THERE IS NOTHING FOR MIND TO DO! Worse, there is no obvious way for mind stuff to ACT on the matter of the brain.
In past blogs, in the Czech version of my book Investigations, and in my Reinventing the Sacred, I have explored, and continue to explore, the hypothesis that the mind-brain system is a quantum cohering, decohering to classicity and recohering again to quantum behavior system in a Poised Realm interposed between fully quantum and classical for all practical purposes behaviors, FAPP. Then on this view, mind does NOT act causally on brain,but decoheres ACAUSALLY to classicity FAPP. I truly believe this is a cogent answer after 350 years to the problem Descartes set us: How can mind act on matter.
To act repeatedly on matter, I must suppose that the mind-brain system can decohere to classicity and recohere to quantum behavior repeatedly. Evidence for this reversibility in the Poised Realm is slowly mounting. We must pay it close heed, for the Poised Realm seems to be a new and profound aspect of reality, neither quantum, nor classical - something new whose physics remains largely to be explored. It is not even clear that "laws" will describe all the behaviors of the Poised Realm at this point in time.
But that brings us to the debate of the past half century about free will. If I am a determinist mind-brain system, I clearly have no free will. The Compatabilists argue that this is fine: we can train the young not to kill little old ladies and behave morally. While this view has proponents, I find it inadequate.
But we confront the horns of a dilemma when we include both classical deterministic physics and "classical" quantum mechanics of closed systems where the unitary evolution of the Schrodinger equation holds, and von Neumann's axiomatization of quantum mechanics is assumed.
If we are deterministic, no free will.
If we are "standard" quantum mechanical as above, then the Schrodinger wave propagates unitarily, meaning that the square of the amplitude of all of the propagating amplitudes, interpretable as probabilities, sum to 1.0. Then via von Neuman, in a measurement event, each amplitude has a probability of being "measured" and becoming suddenly classical, proportional to the square of its amplitude and via a magical von Neumann R process, all the probability weight is put on a SINGLE OUTCOME, which is now the measured and classical outcome. But on the Copenhagen interpretation, which I favor over the multiple worlds or Bohm interpretations, it is entirely acausal and ontological "chance" which of these amplitudes is measured and becomes "classical".
This random process per unit time is Poisson, so gives rise, when integrated, to an exponential fall off, the familiar half life of radioactive decay.
So now, in an attempt to find a free will, suppose that we imagine a standard quantum event, it might as well be a quantum random radioactive decay, bad for my brain but fine for my point. Then I walk down the street, presto the decay occurs, and I kill the old lady.
Am I responsible for this "act of free will"? No, it was quantum random. I have no responsibility.
So we are stuck: If classical, no responsible free will. If quantum no responsible free will.
These are the horns of the modern dilemma about a responsible free will.
Can the Poised Realm, where quantum becomes classical, help escape the horns of this dilemma? Yes, at least partially:
Help comes in the predicted and confirmed processes called the Quantum AntiZeno Effect. Here, as seen in supercooled sodium ions, an emergence of classical behavior happens FASTER than a Poisson process and its familiar exponential half life decay! The experimental results, first of their kind, are in, and fit theory, called a Floquet process. Then the behavior is not Poisson, as in "classical" quantum behavior for a closed quantum system. In an OPEN quantum system and it's environment, the Schrodinger equation does not propagate unitarily, for phase information is lost from the system to its environment. One result is that the behavior of the system is no longer standard quantum mechanics "random" or Markovian. The AntiZeno Effect is clearly non-Markovian.
This means that the Poised Realm escapes the horns of the dilemma. If our mind-brain system is quantum-Poised Realm-classical reversibly, its behavior is neither deterministic nor quantum random. The behavior is something else.
So at a minimum the Poised Realm allows us a very first step to escape the modern horns of the dilemma about a responsible free will.
How much might the Poised Realm help? This is almost entirely unknown, for the behaviors of a system of quantum degrees of freedom coupled to one another, and to the classical system that "embodies" them, and receiving quantum and classical input "information" and "acting on its world via quantum, poised realm and classical behavior,t is almost entirely unknown. Among the issues are these: When a quantum degree of freedom decoheres to classicity FAPP, and remains there for a long time, that would seem to ALTER THE HAMILTONIAN OF THE CLASSICAL SYSTEM ITSELF. Rocks that are 4 billion years old are classical very much FAPP and would be parts of the Hamiltonian any physicist would write down.
But then, the alteration in the Hamiltonian of the classical system alters its own dynamics which must ALSO OFTEN ALTER THE BOUNDARY CONDITION HAMILTONIAN OF THE REMAINING QUANTUM SYSTEM.
More, if classical degrees of freedom can recohere to quantum as begins to seem likely, then when they do, that again MODIFIES THE CLASSICAL HAMILTONIAN, AND THEREBY BOTH THE QUANTUM HAMILTONIAN AND THE VERY SET OF QUANTUM DEGREES OF FREEDOM IN THE SYSTEM.
A first point, a crucial point, becomes this: The above embodied quantum-poised realm-classical system, with quantum and classical inputs and outputs is clearly processing information and "acting on its world". But the above system is absolutely NOT algorithmic. It is not a Turing machine, the idealization of a classical Cartesian machine whose every behavior is absolutely definite. Then given the above example, even in rude form, we need never again be convinced that the human mind MUST BE ALGORITHMIC.
The universe is richer and contains what I want to call Trans-Turing quantum-Poised Realm-classical information processing and acting systems that are anything but algorithmic.
Of course quantum computers are algorithmic, but they remain fully quantum coherent, while these embodied quantum-poised realm-classical systems do not remain coherent and the Schrodinger equation does NOT propagate unitarily in them, nor does emergence of classicity via at least decoherence constitute the R process of von Neumann. We confront something deeply new.
Now comes a deeper problem. Suppose that we construct such a system or better that our mind-brain system is such a Trans-Turing system. Can it have "responsible free will"?
Here is why the problem is hard. Consider an OUTSIDE third person description by me of the behavior of such a system, eg. a device or your mind-brain system operating in the quantum-poised realm-classical worlds where the Possibles of the quantum BECOME IN THE POISED REALM the Actuals of the classical world. I am not allowed to appeal to something outside of this system at its "free will". But then, ALL I have is my third person description of the behaviors of this Trans-Turing system. What constitutes "deciding"? I want to say that a transition from a quantum to a classical behavior of a degree of freedom, from the Possible of Res Potensia via the Poised Realm, to an Actual Classical event, constitutes DECIDING. But what third person grounds do I have to say that such a transition is "a decision"?
I do find this idea attractive. But I am still trapped. Let this transition from quantum to classical via the poised realm be the becoming of a decision. Fine, but is all this wonderful quantum-poised realm-classical new behavior a "responsible free will"?
Here are at least some of the issues: 1) Agency. In physics there are only happenings, no doings. Agents "do things". But given the third person description of the Trans Turing system, there are still only happenings. Where can we get agency and doings?
In Investigations I posited doings in molecular autonomous agents, fully classical systems that reproduced and did work cycles. I still like that, but I "posited" doings, eg as a Wittgensteinian "language game".
Can we do better?
I do NOT know. It seems we need first person experience and hence qualia - my awareness of the redness of red, or my deciding, to get agency without just positing it. How do we get there? I am coming to the slow conclusion that there is no pathway from third person descriptions to agency, hence experience and qualia.
I have blogged about consciousness being participation in "the Possible", Res Potentia. But that too does not give qualia.
Perhaps we could show that consciousness IS participation in "the Possible", for example by showing that 500 Duke undergraduate students concentrating on a two slit experiment could reduce interference patterns, but not if asleep. You see, constructive and destructive interference imply that the "real possibilities" of QM interact non-causally and change the classical outcome, as in the interference pattern. So perhaps we can show that consciousness does have an acausal consequence for quantum interference by reducing it in the two slit experiment. This would support Bohr's belief that mind is somehow "constitutive of the world".
In my blog "To Be Is To Be Perceived" , I made use of a feature of the Shor theorem for correcting decohering degrees of freedom in a quantum computation, that implies that any such correction merely shifts the decoherence from the decohering quantum system to the ENVIRONMENT. To my amazement, this implication of Shor's theorem could yield a conscious observer, the quantum-poised realm-classical observing system, consciously "aware" of the two slit experiment, exporting decoherence from within that observer to the environment, hence reduce two slit interference. Shor, plus the hypothesis that consciousness participates in Res Potentia, the Possible, may yield Bohr's consciousness "constitutive of the world".
But even that amazing result would not suffice to explain qualia.
We all have experiences. Perhaps we just have to accept this as a feature of the entire universe, as A.N. Whitehead does, or perhaps limited to Res Extensa and Res Potentia interacting via the Poised Realm in mind-brain Trans-Turing systems. I know no adequate answer, along with the rest of us.