Tuesday, January 12, 2021

Free will and physics: the next instalment


I’m sorry that I seem to have forced Jerry Coyne to write about a subject he is avowedly tired of, namely free will. But my piece in Physics World inspired him to do so, if only to suggest it is all wrong.

Needless to say, I don’t agree. I’m happy to say why, although it must be at a regrettably even greater length, given that just about every paragraph in his comments is misconceived.

But I’ll give you the short version first. If Coyne really is tired of writing about free will, he could have saved himself a lot of effort. He could have dropped the simple restatements of the “deterministic” case against free will (which were my starting point), and cut all the misrepresentations of what I said, and cut to the chase as follows:

“I don’t understand the scientific basis for Ball’s claim, but my hunch is that a couple of physicists I know would disagree with it. I’ll let readers argue that out.”

So that’s the executive summary. Here’s the rest.

First, a little flavour of the kind of thing that’s to come. At the start of the second half of his critique, Coyne says that my attacks on free will [sic – he means attack on attacks on free will] are misguided because I “do not appreciate that naturalism (determinism + quantum uncertainty) absolutely destroys the libertarian notion of free will held by most people.” This is such a peculiar statement, because my article was suggesting that this notion of naturalism doesn’t undermine free will. It’s not that I don’t “appreciate” that argument; it’s that I don’t agree with it. (I’m not sure quite what the “libertarian notion of free will held by most people” is precisely, because I haven’t asked them.) Surely Coyne of all people knows that convincing arguments are not simply made by declaring them correct by fiat? Isn’t that what he lambasts religious people for doing?

Now, let’s get this bit out of the way: “To say that psychological and neurological phenomena are different from physical phenomena is nonsense,” Coyne declares. This is the first of many plain misrepresentations of what I say. What I say – he even quotes it! – is that psychological and neurological phenomena are not meaningfully adjudicated by microphysics, by which I mean theories that begin with (say) subatomic particles. This is not the same as saying that the neural circuits involved in psychological and behavioural phenomena are not ultimately composed of such particles. The point of my article is to explain that distinction. As we’ll see, Coyne later admits that he doesn’t understand the scientific arguments that underpin the distinction. Hence my abridged version of his diatribe above.

Incidentally, Coyne alludes to experiments that allow us to predict “via brain monitoring what someone will do or choose.” This is presumably a reference to Libet-style experiments, conducted since the 1980s. As he has written on this topic before, I must assume that Coyne knows there has been a great deal of debate in the neurobiological and philosophical literature on whether they pronounce on free will at all. Only those who believe Coyne is correct about free will will absolve him of all responsibility for not mentioning that fact.

Coyne complains that I don’t define free will at the outset (although he seems oddly confident that whatever definition I choose, it is wrong). I don’t define it because I think it is a terrible term, which we seem lumbered with for historical reasons. A key aim of my article is in fact to suggest it is time to jettison the term and to talk instead about how we (and other creatures) make volitional decisions. This is an issue for cognitive neurobiology, and others have made an excellent start on outlining what such an endeavour might look like: for example here and here. I’m not sure if Coyne knows about this work; he makes no reference to it so perhaps I should assume he does not.

But is there really volitional behaviour at all, or is it all predetermined? That’s the key. Coyne admits that we can’t predict “with complete accuracy” what someone will do. Of course, there are lots of situations in life where a great deal of prediction is possible, sometimes simply on statistical grounds, sometimes on behavioural ones, and so on. No one disputes that.

So what do we mean by “with complete accuracy”? This is very clear. It means that, if Coyne is right, an all-seeing deity with complete knowledge of the universe could have predicted yesterday every action I took today, right down to, say, the precise moments I paused in my typing to sip my tea. It was all predetermined by the configuration of particles. 

If that were so, the unavoidable corollary is that everything that currently exists - including, say, the plot of Bleak House – was already determined in the first instants of the Big Bang. 

Now, as far as we know, this is not the case. That’s because quantum mechanics seems to be fundamentally indeterminate: there is an unpredictability about which outcomes we will see, because all we can predict is probabilities. But that just adds randomness, not anything that can be construed as will. So we can say that the plot of Bleak House was determined by the initial conditions of the Big Bang, plus some unpredictable randomness.

As it is unprovable, this is a metaphysical statement. It’s hard to see how we can advance beyond it one way or another. What I’m suggesting is that, rather than get stuck in that barren place, we might choose more profitably to talk about causes. That way, we can actually raises some useful and even answerable questions about why we do what we do, including why Dickens wrote Bleak House.

But Coyne says “Screw cause and effect… as they are nebulous, philosophical, and irrelevant to determinism.” Well, I could just stop here - because it means Coyne has said “Oh, your argument that rests on cause and effect? I’m not even going to think about it.” I’m not sure why he didn’t have the honesty to admit that, but hey. It’s true that causation is a very thorny philosophical issue indeed - but it also happens to be at the core of my notion of free will. Because it seems to me that the only notion of free will that makes much sense is not “I could have done otherwise” (which is also metaphysical, because you could never prove it - if your argument depends on working up from the exact microphysics of the situation, you can never conduct the same experiment twice) but “I - my mind, me as an organism - caused that to happen. Not the conditions in the Big Bang plus some randomness, but me.” And then of course we can argue about what “me” means, and how the mind is constructed, and all the rest of it, and we’ll find that it’s terribly complicated, but we’re arguing and constructing hypotheses and testing them in the right place, which is neuroscience and not microscopic physics.

So everything that follows that statement by Coyne that he’s not interested in debating causation is a sideshow, though it goes on for a very long time. (Later he returns to causation by saying I have confused notions about it. But he forgets to say why, or elects not to.) Still, let’s proceed.

“Is there anything we know about science that tells us that we can “will” ourselves to behave differently from how we did? The answer is no. We know of nothing about physics that would lead to that conclusion.” This is a restatement of the tired old idea that to posit “free will” means evoking some mysterious force outside of physics. I hope I have made it clear that I don’t do that. But let me say it again: I don’t believe there is anything operating when I make a decision beyond (as far as we know them) the fundamental forces of nature acting between particles. What I am saying is that it is wrong, perhaps even meaningless, to speak of all those countless interactions as the “cause” of the behaviour. What caused Dickens to write Bleak House? “Well, in the end, it has to be the Big Bang plus quantum randomness.” Really, that’s the hill you want to die on?

So when Coyne expresses outrage that I say it is “metaphysical” that “underlying our behavior are unalterable laws of physics?”, he has created an obvious straw man. What I in fact said - as careful readers might have noted - is that arguments that “free will is undermined by the determinism of physical law… claim too much jurisdiction for fundamental physics [and] are not really scientific but metaphysical.” This is not the same thing at all - precisely because of my assertion that we must judge such jurisdiction on the grounds of causation.

But straw men are about to appear in abundance. Coyne accuses me of one when I say:

“If the claim that we never truly make choices is correct, then psychology, sociology and all studies of human behaviour are verging on pseudoscience. Efforts to understand our conduct would be null and void because the real reasons lie in the Big Bang.”

This is a strawman, he says, “because none of us deny that there can be behavioral science, and that one can study many aspects of human biology, including history, using the empirical tools of science: observation, testing, falsification, and a search for regularities… Although the “laws” of human behavior, whether collective or instantiated in an individual, may not be obeyed as strictly  as the laws of physics, all of us determinists admit that it is fruitful to look for such regularities on the macro level—at the same time we admit that they must comport with and ultimately derive from the laws of physics.”

I find the extent of Coyne’s miscomprehension here astonishing. He goes on: how dare I call behavioural or social sciences pseudoscience, or history “just making up stories”, or say that behavioural regularities are just “peculiar coincidences” and nothing to do with evolution!

Now, there are a few clues that perhaps this is not what I’m saying or believing - like for example the fact that I wrote an entire book (more than one, actually) on how ideas from physics about how regularities and patterns arise in complex systems can be of value in understanding social science and economics. If Coyne had given a damn about who this chap he was criticising actually was, he might have discovered that and - who knows? - perhaps experienced a moment of cognitive dissonance that led him to wonder if he was actually understanding this article at all. That could have saved him some trouble. Still, onward.

In any case, he says, none of us determinists believe all those terrible things about the behavioural sciences and all the rest! It’s a straw man!

But my point is this: Sure, you don’t think those things. You all (I suspect) recognise the value of the behavioural and social sciences and so forth. But that’s because you haven’t really examined the implications of your belief.

Here’s why. If you believe that everything that happens (lets put aside the complication of quantum indeterminism for now) was preordained in the Big Bang - that the universe unfolds inexorably from that point as particle hits particle - then you really cannot sustain a genuine belief in behavioural sciences as true sciences. Let’s say that a behavioural scientist deduces that people behave a certain way, Y, in the presence of influence X, and so goes on to conduct an experiment in which X is withheld from the subjects, to see if their behaviour changes. And it does! So, there’s a fair case to be made that X is a causal influence on behaviour. 

But it’s not really so, is it? What you have to believe is that the conditions in the Big Bang caused a universe with people in it that are of the nature that behaviour Y tends statistically to be correlated with condition X. When we say “X causes Y”, we don’t mean that. There’s no genuine causal relationship involved; it’s just, as I say, “an enumeration of correlations”. I don’t care about dictionary definitions of “pseudoscience” (and Coyne only does, it seems, because he thinks I’m calling behavioural science a pseudoscience and wants to prove me wrong). But I do know that it is very common in pseudoscience to mistake correlation for causation. 

I guess it might be possible to imagine a kind of science that, while it employs “observation, testability, attempts at falsification, and consensus” while never rising above the level of documenting correlations, and never imputing any sort of causal mechanism. But I’m not sure I can think of one. What I am saying is that, if Coyne’s vision of determinism were true, behavioural sciences could never talk factually about mechanism and causation - or if they did, they’d not be speaking any kind of truth, but just a convenient story.

Still, I guess the best way is to find out. We could ask behavioural and social scientists if they are content to regard the objects of their studies as automata blindly carrying out computations – which is what Coyne’s view insists – or whether (at least sometimes) we should regard them as agents making genuine decisions. I’m pretty sure I know already the answer many neuroscientists would give, because some have told me.

At any rate, the basic point should be clear now: you don’t refute a reductio ad absurdum by crying “But that’s absurd!”

Well, on with the cognitive dissonance. Coyne says I “give the game away” by betraying that I can’t believe in free will after all, because I say:

“Classical chaos makes prediction of the future practically impossible, but it is still deterministic. And while quantum events are not deterministic – as far as we can currently tell – their apparently fundamental randomness can’t deliver willed action.”

“In other words” Coyne says, “physics, which Ball admits has to comport with everything at a “higher level”, can’t deliver willed action. Thus, if you construe free will in the libertarian, you-could-have-done-otherwise sense, then Ball’s arguments show that we don’t have it.” I’m not sure what to make of this. Does Coyne not realise that, by stating these things at the outset I am aiming to lay out the case to be addressed, and to avoid some spurious defences of free will that pin it all on some kind of fundamental indeterminacy? Does he not realise that, when one starts off presenting an argument by saying “Well, here’s the thing I’m seeking to challenge”, it is not a very impressive counter-argument to say “Ah but you just said that very thing, so you must believe it too!”?

Next. Evolution: I could have guessed this would be a sticking point! (Actually I did; that’s why I raised it.) 

I say:

“What “caused” the existence of chimpanzees? If we truly believe causes are reducible, we must ultimately say: conditions in the Big Bang. But it’s not just that a “cause” worthy of the name would be hard to discern there; it is fundamentally absent.”

In response, Coyne says:

“If Ball thinks biologists can figure out what “caused” the evolution of chimps, he’s on shaky ground. He has no idea, nor do we, what evolutionary forces gave rise to them, nor the specific mutations that had to arise for evolution to work. We don’t even know what “caused” the evolution of bipedal hominins, though we can make some guesses. We’re stuck here with plausibility arguments, though some assertions about evolution can be tested (i.e., chimps and hominins had a common ancestor; amphibians evolved from fish, and so on). And yes, that kind of testing doesn’t involve evoking the laws of physics, but so what?”

It’s hard to know where to begin with this. What he is talking about in terms of efforts to understand the evolution of chimps is precisely the same as what I’m talking about: one might look, for example, at morphological changes in the fossil record, and if possible at changes in genomics, and how they correlate. One does comparative genomics. One might frame hypotheses about changes in habitat and adaptations to them. In other words, I raise the notion of a “theory of chimp formation” as another reductio ad absurdum. I don’t believe biology should be aiming for such a thing, or that it is even meaningful. Rather I think it should be doing precisely what it is: making hypotheses about how chimps evolved on the basis of the available evidence.

The issue, though, is whether one regards this as renormalised physics. Coyne does. I am not sure all his colleagues would agree. I don’t mean that they would say (as he might), “Well, what we’re doing is just a more useful higher-level abstraction of the basic physics.” I suspect many would say that thinking about evolution as coarse-grained physics is of no value to what they do, and so they (rightly) don’t bother even to give it any thought.

But this does NOT mean there is anything except physics operating at the microscopic level of particles.

What does it mean then? That gets to the crux of the matter. What I’m suggesting is that it means that we shouldn’t be considering causation as only and entirely top-down. 

That is the point of the piece. And finally, after much huffing over straw men, Coyne gets to it. What does he have to say about it?

It is, he says, “something I don’t fully understand”. 

OK, so perhaps it would be best for him to leave it there. Sadly, he does not.

“As far as I do understand it”, he says, “it doesn’t show that macro phenomena result from the laws of physics, both deterministic and indeterministic, acting at lower levels. To me the concept is almost numinous.”

I don’t even know what this means. “It doesn’t show that macro phenomena result from the laws of physics acting at lower levels.” Huh? What then does he think it does show? That there’s some mysterious non-physical force at work? I’ve really no idea what he is trying to say here.

The idea of top-down causation, in the forms I’ve seen it, shows in fact that systems in which there are nothing but the laws of physics acting at lower levels nevertheless display causation that can’t be ascribed to those lower levels. 

Remember causation? That thing my argument was based on? Does Coyne agree with the arguments for the existence of top-down causation in complex systems? If not, why not? 

But it seems he doesn’t much care: he’ll “let readers argue this out”. Still, he adds, “if physicists like Sean Carroll and Brian Greene are not on board with this—and as far as I know, they aren’t—then I have reason to be skeptical.”

Really? An “argument from authority” – and one moreover that discounts the authority of Nobel laureates such as Phil Anderson? That’s the basis of his case?

Does he even know the position of Sean Carroll and Brian Greene on this? Has he asked them? Is there any evidence that they have considered such arguments? (Greene doesn’t mention it in his book.)

(By the way, I don’t think I “denigrate” (=“criticise unfairly”) Greene’s view in Until the End of Time. I simply disagree with it. If Coyne had more curiosity, it would have been very easy to discover that, while I bring up this point in my review of Greene’s book, I also had some good things to say about it.)

(And incidentally, Sean Carroll has written on top-down causation, but not in a way that is germane here. In The Big Picture, he dismisses the need to invoke it in snowflake formation - and I agree with him there. And in his blog here, he criticises John Searle’s view of consciousness from this perspective. But Searle believes consciousness is somehow a non-physical entity beyond science. That has nothing to do with the work I allude to. Where top-down causation matters is in discussing questions of agency.)

Truly, I had to ask myself, this is it? The reason Coyne thinks my piece is wrong is because (part from reasserting the same tired old arguments about determinism) he doesn’t fully understand the science on which they’re based, but he suspects a couple of his pals might not buy it and so that’s good enough for him?

Oh well. Onward.

Coyne says I’m wrong to say that dispelling the idea of free will has no implications for anything. Actually I don’t say that at all (I think I’m sensing a pattern here). I say it is rather telling that those who claim to have dispelled free will seem oddly keen to say we should go on acting as though it really is a thing.

No we don’t, Coyne says! We say that because there’s no free will, we should be “less retributive, more forgiving.” And this is precisely my point. If you don’t believe in free will, why should you be retributive or forgiving at all? In that case, none of what we do is our fault, because it was ordained in the Big Bang (plus randomness). That’s all there is to it. 

This is what I mean: those who deny free will don’t have the courage of their convictions. They feel obliged to resurrect it, or the ghost of it, to avoid having to absolve us of all responsibility. But they don’t seem to know how to do that, other than with arm-wavy statements like this: “I still think people are “responsible” for their actions, but the idea of “moral” responsibility is connected with “you-could-have-chosen-to-do-otherwise.”” So they are responsible but not morally responsible? Then responsible in what way, exactly? What kind of responsibility can stem from predeterminism? He doesn’t say.

Why, if there’s no free will, would we take any action at all to try to change people’s behaviour? After all, we can’t then have a genuinely causal influence on what they do. I guess in this case free-will deniers will say to themselves: “well, I know I’m not really deciding to do this, it’s just my automaton-brain playing out the 13.8-bn-year stage of the Big Bang, but then again, if I don’t then I suspect that 13.8-bn-year-old plan will include this person reoffending, and so I guess I’d better, but all the same I’m not choosing this but just telling myself I am because that’s what brains do, and so I guess I’m stuck with this belief that I personally have a causal effect on the future, but I don’t, and I must deny it, but there’s actually no must about it because that concept doesn’t exist either…” Or something. God knows what their narrative is. Perhaps it’s just “well I still have this gut feeling that that person is responsible in some way for what they do but I don’t really know what that means.”

What Coyne is talking about, I suspect, is the recognition that people vary in the degree to which they can truly decide on their actions. There are all kinds of influences that determine this: their past history, their social circumstances, the specific nature of their brain (part innate, part conditioned), whether they’ve just eaten… There’s a gradation from volitional to totally non-volitional (like reflexes). In a fair and just society, we already recognise this. So we try to make our rules and judgements by considering such factors, and trying to make a fair assessment of degrees of culpability, and thinking about what - if we punish someone for their actions - we might hope to achieve by it. We work at the macro level at which we can think meaningfully about cause and effect. We don’t argue about physics and the Big Bang. We don’t do that not because that would be an awfully hard way to reach a judgement about the situation, or because we lack the computational resources, but because we know it would be meaningless.

Because this is by no means the first time I’ve seen smart people transmuted into abysmal readers, I’m genuinely curious about what makes that happen. I have a hypothesis, though it would be hard to test. I think they start by reading the title or headline, thinking “Well I profoundly disagree with that”, and then let that preconceived judgement prevent them from actually reading the argument and assessing the rhetorical or logical trajectory of the piece. Instead they just read each sentence at a time and – without asking “Is this part of the author’s position, or the position he/she is setting out to attack?”, “Is this a rhetorical structure?” and so on – just decide for themselves what they think the sentence means and then consider how they can disagree with it. In Coyne’s case I fear that situation is compounded by his evident conviction that dismantling free will is part of his crusade against “religionists.”

Sometimes when I see this happen, I’m forced to wonder how science sustains any discourse at all. But fortunately, it seems to manage.

I guess I have been harsh here in some places, but I’m happy to take responsibility for that. I do think it was me that chose to write this, and not the Big Bang. And you do too really, don’t you?

PS If you read Coyne’s second article and go looking for my piece in Physics Today, you won’t find it. It was in Physics World. To judge from a glance at his comments thread, that’s a moot point anyway, as I saw little sign that most commenters were bothering to look at the article anyway. The one chap who evidently did, agreed with me.