Most of what I've said in this connection has to do with God's freedom to act in the world within the limits of the (true) laws of physics, not with the question of human free will. If classical determinism were true and God chose to act kenotically then God would have no freedom in what he did in the world. Petitionary prayer would be pointless because whether or not it would rain tomorrow or a tumor would shrink would have been determined at the beginning of the world. Of course this is quite consistent with Enlightenment deism. But because of quantum & chaos theories (whose relationship I won't go into now), classical determinisn isn't true of the real world. God therefore has some (though not unlimited) freedom to decide what the outcome of various events will be without "violating the laws of physics". (& a fortiori, God has such freedom if the laws of physics are violated.)
Whether or not the same considerations apply to human free will depends to a large extent on how one thinks of the mind-body problem. If there is a mind in some sense separate from the body then one might make the same sort of argument as above for humans: The non-physical mind has some choice about what to do. It's harder to make that argument for the type of non-reductive physicalism for which N. Murphy et al have argued, partly for the types of reasons Dave S. suggests. I find non-reductive physicalism to some extent appealing but also see problems with it, this being one of them.
The difference is that God is not limited to the physical world, while the question of whether or not human minds are so limited is debated. OTOH the fact that we speak of a non-physical "mind of God" challenges physicalists' claims that material brains are a necessary condition for the existence of minds.
Then to your 2d paragraph. The standard description is as follows. The wave function - which represents the quantum mechanical state - of any system (e.g., an atom) at a given time is a sum of functions which correspond to different values of a dynamical quantity, such as energy. (What these values are depends on the nature of the system.) This initial state in general has no definite energy but the square of its absolute value is a probability distribution for different possible energies. When the energy of the system is measured, the state "collapses" (or is "reduced" or "projected") onto one of those states with a definite energy. The relative probability of collapsing to a particular state with a particular energy depends on how heavily that state contributes to the sum that made up the initial state. Unlike the change with time of the state of an undisturbed system, which is described in a deterministic way by the Schrodinger equation, the change that is produced by the measurement process is not predictable according to traditional QM and is not deterministic. From the initial state we can only predict the probability of any given allowed energy being the result of the measurement.
The cause of this "collapse" is the measurement. It is often said that it happens because any measurement must involve some physical interaction with the system, such as scattering a photon off it. But while this can give people the comforting feeling that there is some intuitive reason for the change, it's too simplistic. The collapse can also be caused by an "experiment with negative result." E.g., let the system be a electron in a magnetic field, so that there will be 2 possible states with different energies, spin up and spin down (relative to the magnetic field). The state of a single electron will be a linear combination of states with spins up and down. If that electron is fired at the traditional double slit apparatus, it will go through slit A if its spin is up and slit B if its spin is down. Now suppose we send a photon toward slit A and see nothing. We then know that the electron has gone through slit B, and the state has collapsed to spin down even though there was no physical interaction between the measuring apparatus and the electron.
That, however, is not the most serious aspect of the causality problem. Granted that the state collapses because of a measurement, standard quantum theory gives no reason why it collapses to any particular state with a particular energy in a given measurement. In the previous example, there is no reason why, in that specific measurement, the state collapsed to spin down and the electron went through slit B. Hence the apparent failure of the principle of sufficient reason.
Those knowledgable about QM will realize, and I trust excuse, my glossing over potential technical complications - complete sets of commuting observables, continuous spectra, degeneracy &c.
Shalom
George
http://home.roadrunner.com/~scitheologyglm
----- Original Message -----
From: Cameron Wybrow
To: asa
Sent: Tuesday, July 07, 2009 4:56 PM
Subject: free will and indeterminacy (was Re: [asa] observational vs. theoretical differences)
For what it's worth, and not out of any disagreement with anything George Murphy said, I agree with Dave Siemens about randomness. Random acts aren't free. And I've always had a problem, for that reason, with arguments that try to ground free will in quantum indeterminacy. If an electron in my brain suddenly "blips" and makes an arbitrary and utterly unpredictable "quantum leap" of some kind, how does that enable me to will good rather than evil? Either the blip necessitates my choice for the good, in which case my choice is not free (hence not praiseworthy), or it merely enables my choice for the good (by somehow cancelling out, momentarily, the mechanical side of my nature), in which case my choice to do good rather than evil still rests ultimately on something in me other than quantum physics. Sooner or later, if we really believe in freedom, we have to come back to traditional (Platonic and Christian) language about the soul, language which has been quite unfashionable now for quite a long time, even among Christians (I might almost say especially among Christians).
P.S. I find George's ruminations about quantum indeterminism and divine action helpful, because he acknowledges that QI isn't a "magic bullet" in relation to evolution, but is only a possibility that requires more pondering. I like his question "what collapses all the others?" This is an aspect of quantum theory that I've never understood. Are the changes dealt with under "indeterminacy" understood by physicists to be literally causeless? If not -- if there is a cause for each "quantum event" -- then how can such a cause not be law-abiding? And if the cause is law-abiding, why are all changes not (in principle, anyway) predictable? I find it impossible to separate the notion of "cause" from the notion of "regularity" or "law-abiding behaviour". Is that a macroscopic prejudice? Does "cause" mean something different in the quantum world than in the macroscopic world? If so, should the word "cause" even be used? My popular science reading in this area is doubtless out of date. Is there a good, currently valid book or article, written in layman's language, that discusses causality, law, determinism, indeterminism, etc. in relation to quantum theory?
Cameron.
----- Original Message -----
From: dfsiemensjr
To: GMURPHY10@neo.rr.com
Cc: dfsiemensjr@juno.com ; wybrowc@sympatico.ca ; asa@calvin.edu
Sent: Friday, July 03, 2009 5:43 PM
Subject: Re: [asa] observational vs. theoretical differences in scenarios; a direct question
George,
I wasn't accusing you of trying to fit God's activity into QM. But you did clarify the matter of causation. My question involved God's control beyond anything that science could detect. What I recognize is that QM cannot be the basis of free will, which demands the individual's control of their action. A random act is no more free than a strictly determined one.
As to the principle of sufficient reason, perhaps it requires supplementation with the principles of unrecognized reason and imperceptible reason.
Dave (ASA)
On Fri, 3 Jul 2009 08:28:55 -0400 "George Murphy" <GMURPHY10@neo.rr.com> writes:
Dave -
I didn't mean to suggest that QM would function as a "mask of God" any more than any other aspect of the world does. In fact, the idea that God collapses wave packets directly would mean that at a fundamental level there is no 2dary causality. That's why, even though I think the idea of God's action at the quantum level needs further exploration, I'm uneasy about it. If God collapses all wave packets - i.e., if God is directly responsible for the "condensation" of all probability distributions into certainties - then we've simply resintroduced what Barbour calls the "classical" model of divine action in which God acts as the dictator of the world to do everything directly. Creatures have no causal role at all. OTOH, if God acts directly to collapse only some wave packets - in order to direct evolution in particular ways, e.g. - then we have to ask what collapses all the others. I may be able to abandon the peinciple of sufficient reason, but a principle of "some but not all sufficient reason" seems quite unsatisfactory.
Shalom
George
http://home.roadrunner.com/~scitheologyglm
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Received on Tue, 7 Jul 2009 21:55:58 -0400
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