You might be interested in what physicist Sabine Hossenfelder has written on the subject of free will. For my part, I believe Edwards’ attempt to rescue free will from scientific objections is unsuccessful, and that Professor Coyne’s criticisms of his arguments are valid ones, but I have a proposal of my own, which I’ll outline below.
First, here’s a sample of what Dr. Hossenfelder has written on the subject, on her blog.
In an article titled, How to live without free will (Thursday, May 02, 2019), Hossenfelder writes:
"Physics deals with the most fundamental laws of nature, those from which everything else derives. These laws are, to our best current knowledge, differential equations . Given those equations and the configuration of a system at one particular time, you can calculate what happens at all other times.
"That is for what the universe without quantum mechanics is concerned. Add quantum mechanics, and you introduce a random element into some events. Importantly, this randomness in quantum mechanics is irreducible. It is not due to lack of information. In quantum mechanics, some things that happen are just not determined, and nothing you or I or anyone can do will determine them.
“Taken together, this means that the part of your future which is not already determined is due to random chance. It therefore makes no sense to say that humans have free will.”
Hossenfelder also mentions that Schrodinger’s equation implies determinism in her comments. See here.
She also discusses the causal exclusion problem in her comments, as an argument against free will. See here.
Finally, Hossenfelder writes that she has already discussed top-down causation and why that won’t salvage free will. See her 2017 article,
(the full essay can be found here).
A few relevant excerpts:
“The causal exclusion argument combined with effective field theory is the main reason
why physicists believe that reductionism is correct. Another reason for their confidence is the absence of any known example of strong emergence , ie a case in which the properties of a system at large scales are known to be not calculable from the underlying theory. (Though there are certainly many examples in which they are not calculable by presently known methods.)”
But she also adds:
"There isn’t a priori any reason why it must be possible to continue the constants of the theory at high resolution to any lower resolution. If you run into a point where the coupling can’t be continued, you will need new initial values that have to be determined by measurement. Hence, strong emergence is viable …
"With this, the ball is back in the court of physicists. The argument that effective field theory proves reductionism, even though no one is able to at least derive the properties of an atomic nucleus from QCD, undeniably has an air of physicists’ hubris to it. It is thus only fair on those philosophers who like to believe that strong emergence exists that physicists first show that the coupling constants of a quantum field theory can always be continued to low energies for physically realistic systems.
She concludes:
"In this essay, I have presented a new example for strong emergence. While this example is purely hypothetical, it illustrates how truly new fundamental laws could emerge for composite objects, at least theoretically.
“I herewith grant you permission to believe in free will again.”
A third essay Hossenfelder has written on the subject is: Limits of Reductionism (Thursday, July 05, 2018):
"For many years I was convinced that the only way to make free will compatible with physics is to adopt a meaningless definition of free will. The current status is that I cannot exclude it’s compatible …
"That is as long as you believe – as almost all physicists do – that the laws that dictate the behavior of large objects follow from the laws that dictate the behavior of the object’s constituents. That’s what reductionism tells us, and let me emphasize that reductionism is not a philosophy, it’s an empirically well-established fact. It describes what we observe. There are no known exceptions to it …
It occurred to me some years ago, however, that there is a much simpler example for how reductionism can fail. It can fail simply because the extrapolation from the theory at short distances to the one at long distances is not possible without inputting further information. This can happen if the scale-dependence of a constant has a singularity , and that’s something which we cannot presently exclude…
I do not currently know of any example for which this actually happens. But I also don’t know a way to exclude it.…
It will take more than this to convince me that free will isn’t an illusion, but this example for the failure of reductionism gives you an excuse to continue believing in free will."
To sum up: I think it is fair to conclude that the scientific case against free will remains unproven. However, I also think (having read her recent articles) that hand-waving articles to strong emergence and top-down causation won’t do, either. Top-down causation won’t save the day unless the deterministic Schrodinger equation does not apply to large-scale systems - and we currently have no empirical scientific evidence that this is the case. And even if that were the case, we still need to put forward a workable model of how my free choices could affect physical events.
Sophie Gibb has put forward a model which preserves the closure of the physical, in which mental events (such as desires and choices) play a preventative rather than a causal role, in her 2015 article, Defending Dualism (Proceedings of the Aristotelian Society, 115, 2, p. 131-146). However, I find this model unsatisfying because it limits the role of mental events (such as choices) to preventing other mental events from interfering with physical processes.
Personally, I prefer a model I first suggested back in 2012 and again in 2016 - see here. I can see now that most of my remarks in the article I wrote on top-down causation are beside the point, as top-down causation, by itself, won’t guarantee freedom. However, I also put forward a model as to how free choices would be perfectly compatible with the physical causation of bodily movements, and would not require the input of additional “psychic energy”.
The suggestion I made related to quantum-level randomness. Hossenfelder insists that “[i]n quantum mechanics, some things that happen are just not determined, and nothing you or I or anyone can do will determine them.” Fair enough, but this indeterminacy occurs at the micro-level. However, micro-level indeterminacy and randomness is perfectly compatible with macro-level non-randomness, as I explained here. Moreover, I propose that our choices work by ruling out certain macro-level outcomes which are incompatible with our wishes, in a manner similar to Libet’s famous “free won’t”:
…[I]t is easy to show that a non-deterministic system may be subject to specific constraints, while still remaining random. These constraints may be imposed externally, or alternatively, they may be imposed from above, as in top-down causation. To see how this might work, suppose that my brain performs the high-level act of making a choice, and that this act imposes a constraint on the quantum micro-states of tiny particles in my brain. This doesn’t violate quantum randomness, because a selection can be non-random at the macro level, but random at the micro level. The following two rows of digits will serve to illustrate my point.
1 0 0 0 1 1 1 1 0 0 0 1 0 1 0 0 1 1
0 0 1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1
The above two rows of digits were created by a random number generator. The digits in some of these columns add up to 0; some add up to 1; and some add up to 2.
Now suppose that I impose the non-random macro requirement: keep the columns whose sum equals 1, and discard the rest. I now have:
1 0 1 1 1 0 0 0 0 0 1
0 1 0 0 0 1 1 0 1 1 0
Each row is still random (at the micro level), but I have now imposed a non-random macro-level constraint on the system as a whole (at the macro level). That, I would suggest, what happens when I make a choice.
Top-down causation and free will
What I am proposing, in brief, is that top-down (macro–>micro) causation is real and fundamental (i.e. irreducible to lower-level acts). For if causation is always bottom-up (micro–>macro) and never top-down, or alternatively, if top-down causation is real, but only happens because it has already been determined by some preceding occurrence of bottom-up causation, then our actions are simply the product of our body chemistry – in which case they are not free, since they are determined by external circumstances which lie beyond our control. But if top-down causation is real and fundamental, then a person’s free choices, which are macroscopic events that occur in the brain at the highest level, can constrain events in the brain occurring at a lower, sub-microscopic level, and these constraints then can give rise to neuro-muscular movements, which occur in accordance with that person’s will. (For instance, in the case I discussed above, relating to rows of ones and zeroes, the requirement that the columns must add up to 1 might result in to the neuro-muscular act of raising my left arm, while the requirement that they add up to 2 might result in the act of raising my right arm.)
I’d be interested to know what @dga471 thinks of this suggestion. Do you think it could work, Daniel?
N.B. In the model sketched above, I have assumed a “Christian materialist” model of the mind (such as might be defended by Jehovah’s Witnesses, Seventh Day Adventists and Christadelphians), for the sake of argument. If one wishes to maintain that free choices are immaterial events (as most Christians do), then one must suppose that immaterial events are somehow able to impose macro-scale patterns on random micro-level events occurring in the brain. I discuss the interaction problem here and argue at further length why Thomism cannot dodge this problem here and here. Cheers.