I can't believe I'm about to write yet another essay on free will. The thing is, the wretched topic is just not going to go away. And for obvious reasons: it is one of the classical problems that, in the words of philosopher Wilfrid Sellars, require a reconciliation of the scientific and manifest images of the world -- that is, how science looks at the issue vs how the rest of us do.
The scientific image of free will seems to strongly hint that there is no such thing. We live in a universe that works according to the laws of physics, and more broadly is governed by a web of cause and effect. If by "free" we mean that human beings somehow have the ability to transcend such laws then science tells us that we have no free will. Unless you believe in miracles, that is.
In sharp contrast, the "manifest" image, that is, the world as it appears to us humans, just as strongly hints at the existence of free will. When I sat down in front of my iPad a new minutes ago to start typing this essay, I briefly considered writing about another couple of topics instead: process metaphysics or a reply to a misguided article about the usefulness ancient philosophy published recently in the Times Literary Supplement (no worries, both of those are forthcoming). But I decided to write about free will instead. That decision came with the unshakable feeling that of course I could have chosen either of the other two.
You see, then, why so many keep arguing about free will, and why the topic has such a grip on both professional philosophers and the general public. On my part, I arrived years ago at what I consider a satisfactory reconciliation between the scientific and manifest images of free will: compatibilism. This is a position that rejects so-called "contra-causal" (or libertarian) free will, because I believe that nothing happens in the universe without antecedent causes. Call it the no-miracles clause, if you will.
Compatibilism is also a position distinct from hard determinism, the notion that there is no coherent sense in which we have free will because we are like puppets whose strings are moved by the forces of the universe. We are not puppets, because the cosmic web of cause-effect goes straight through us. Things do not just happen to us, we are co-causes of our decisions, because that's what a human being is: a highly sophisticated decision-making machine, capable of altering its own ability to make decisions by applying reason recursively to its own behavior. In lay terms: we think about stuff, and we learn from our experiences.
If compatibilism doesn't satisfy you because you want "real" free will, too bad. You are asking for something that would break the laws of nature and cannot be had. If compatibilism doesn't satisfy you because you don't think there is free will even in the modest compatibilist sense, then good luck navigating the human world of values, oughts, shoulds, and so forth.
Now that we've got the preliminaries out of the way, let me address a provocative, but ultimately deeply flawed, I think, article by physicist George Ellis published in Aeon, with the original title "Here's why so many physicists are wrong about free will." (As an aside, I've never understood why Aeon publishes an article with a certain title, then later on changes it without any other alteration to the article. Oh well.) I've met George a number of times, and he is a brilliant thinker. And yet.
George begins with presenting the standard hard determinist position: the universe is causally closed, meaning that the laws of physics are necessary and sufficient to describe everything that happens within it. This means that if one had enough information about the initial conditions of the universe (the Big Bang) and the laws themselves, plus an enormous capacity for accurate computation, one would, in theory, be able to predict the unfolding of every event, at any time. Including my decision a few minutes ago to write this essay. And yours to read it.
Please note that the hard determinist does not claim that anyone will ever be able to actually predict everything. But the reason nobody probably ever will is not a matter of ontology (i.e., how the world works) but rather simply of epistemology (i.e., how we know about the world -- see here for the relationship between the two). Since human beings have what philosophers call limited epistemic access to the world (i.e., we don't know enough, we are not smart enough, and we don't have the necessary computational resources), we will not be able to make universal predictions. But this is a reflection of our limitations, not of the way the universe works.
George's first move against hard determinism is predictable, and woefully inadequate. He writes: "At very small scales, quantum theory underlies what's happening in the world. Heisenberg's uncertainty principle introduces an unavoidable fuzziness and an irreducible uncertainty in quantum outcomes. You might know the value of one variable, such as a particle's momentum, but that means you can't accurately detect another, such as its position. This seems to fundamentally undermine the allegedly iron-clad link between initial data and physical results."
No, it really doesn't. There can be two reasons for such "fuzziness" at the quantum level, as George knows very well. One possibility is that the fuzziness is only apparent, since after all the equations of quantum mechanics are deterministic. The other is that the fuzziness is real at the level of the phenomena. We don't currently know. We may know when the next fundamental physical theory, reconciling quantum mechanics and general relativity, will see the light (if that's ever going to happen).
Either way, one does not get free will. One gets either the appearance of free will (if the fuzziness is only apparent), or a random component added to our decision making (if the fuzziness is real). Random will is most decidedly not the same as free will.
Fortunately, George decided not to focus on this particular aspect of the discussion, which, he says, is "controversial." Instead, we are treated to a rather in-depth description of the molecular mechanisms underlying causation in the human brain. We learn, of course, about DNA, RNA, proteins, enzymes (a type of protein), ion channels, and so forth. To what end?
As George puts it: "[All of] this means that, to link physics and biology, we need to look at the theory that underlies molecular shape. And that theory is quantum chemistry, based in the fundamental equation of quantum physics: the Schrödinger equation. ... So the actual question is: does the Schrödinger equation, together with the initial state of the wave function describing everything that existed in the early Universe, determine everything I think today because it determines the states of all the biomolecules in my body?"
A hard determinist would answer: yeah, duh! But George reassures us that it ain't so: "The confounding thing for free-will skeptics is that all outcomes don't depend only on the equations and the initial data. They also depend on constraints." What constraints, exactly, and how do they work their magic?
"When constraints vary, outcomes are not determined by initial conditions; they depend on the way that the constraints change with time. In the case of the biomolecules that underlie the existence of life, it's the shape of the molecule that acts as a constraint on what happens. These molecules are quite flexible, bending around joints rather like hinges. ... In this way, biology can reach down to shape physical outcomes. It changes constraints in the applicable Schrödinger equation."
Wait, what? The "constraints" George is referring to, having to do with the shape and functioning of bio-molecules are obviously themselves the results of the laws of physics. Because bio-molecules are, in turn, made of electrons, quarks, and all the rest. And such constraints are certainly not the result of my thoughts and choices, they are the result of biochemical evolution. So why would a physicist neglect this not so little detail in his account?
Because George believes in a controversial concept known as downward causation, as hinted at by the next to the last sentence in the previous quote: "biology can reach down to shape physical outcomes."
Downward causation is a term invented in 1974 by philosopher and social scientist Donald T. Campbell, and it refers to causal links originating from higher levels of a system and effecting lower-level parts of that system. The standard example, which is highly pertinent to the free will debate, are mental events, which are said to act as causes of certain physical events.
For instance, a "mental event" occurred in my brain about half an hour ago, an event that can be described roughly like this: "I'm tired of reading, I feel like writing. Let me work on the first weekly essay for my readers. I think I'll write about George Ellis' misguided take on free will." That mental event, obviously caused me to get up from my couch, put away my book, sit down at my desk, open my iPad, and start typing. It is also co-causing you to read what I wrote.
The problem is that the way I just put things was to exploit a certain level of description of the events, a level that is useful to communicate to my readers, because it focuses on macroscopic descriptions of mental and physical happenings. But of course we know that my thoughts are not things, they are processes caused by molecular-level changes in my brain; which in turn are caused by atomic and subatomic interactions. Which means that there is no such thing as downward causation. Downward causation only appears to be operating because of the way we talk about things. This is what happens when one is not careful about balancing the manifest and scientific images of the world, mistaking the first one for the second one.
Indeed, George explicitly points to this issue, apparently without realizing that it is a problem for his position (possibly because he hasn't read Sellars): "What determines which messages are conveyed to your synapses by signaling molecules? They are signals determined by thinking processes that can't be described at any lower level because they involve concepts, cognition and emotions in an essential way. ... Psychological experiences drive what happens. Your thoughts and feelings reach 'down' to shape lower-level processes in the brain by altering the constraints on ion and electron flows in a way that changes with time. ... None of those qualities -- sympathy, fear, guilt -- occur at the ion or synapse level. These high-level mental operations act down to alter the shape of ion channels, and so change the motions of billions of ions and electrons in your brain."
Sellars defended his distinction between the scientific and manifest images of the world precisely on the ground that scientific language does not include things like sympathy, fear, guilt, or prescriptive judgments such as "I should do X." But Sellars, unlike George here, did not think that there was some mysterious qualitative separation between the two realms. Rather, what is going on is that we describe things differently, using different languages, depending on how useful those languages are for the task at hand.
To use the psychological level of description (and accompanying language) to explain why I decided to write this essay is perfectly adequate, and in fact works far better, for practical purposes, than engaging in a long and convoluted talk about firing synopsis, enzymes, and quarks. But this does not at all imply that -- ontologically speaking -- there is anything above and beyond the fundamental level of reality and whatever behaviors emerge from the interactions among large number of particles at that level.
Ah, I just mentioned the magic word: emergence. This is another controversial concept, which comes into two very different flavors. George believes in what is called strong emergence, while I think the evidence only shows the existence of weak emergence. The distinction is crucial.
George writes: "Of course, nothing about molecular biology contradicts the physics that underlies all material existence. Rather, it provides an extraordinarily complex context where things work out according to that context. Even though our brains are indeed made up of fundamental particles, high-level function emerges through the interaction of upward and downward causal processes."
But how exactly do high-level functions emerge from the interaction of causal processes? The determinist and compatibilist story is that such emergence is one of unidirectional cause-effect: lower level phenomena and interactions cause higher level phenomena and interactions. This is termed weak emergence, and it means that any change in the higher level must be caused by some change at the lower level. Otherwise, we are back to miracles again.
Strong emergence, by contrast, claims that certain properties appear de novo, as it were, at higher levels. But if that were the case, two things would have happened: (i) a break in the causal web; (ii) the generation of novel information from nothing. Both of those would constitute a violation of the laws of nature as we understand them. Of course, it is always possible that we don't have a good grasp of the laws of nature, and that somehow the principle of conservation of information can, in fact, be violated. But that's a tall order of business, and it will take far more than a quick nudge toward neuronal firing and ion channels to take it seriously.
Is it possible that whatever new physics will take over after we'll be able to reconcile quantum mechanics and general relativity will have room for strong emergence? Sure, it's possible. But George isn't waiting for that to happen, he claims we have good reasons to accept downward causation and strong emergence right now. We don't.
Why does any of this matter? George explains: "If you seriously believe that fundamental forces leave no space for free will, then it's impossible for us to genuinely make choices as moral beings. We wouldn't be accountable in any meaningful way for our reactions to global climate change, child trafficking or viral pandemics. The underlying physics would in reality be governing our behavior, and responsibility wouldn't enter into the picture. That's a devastating conclusion. We can be grateful it's not true."
But that is not the "devastating" conclusion we get from compatibilism. We are "responsible" for our choices because we are choice-making machines. It is entirely irrelevant whether those choices could have been predicted from the Big Bang or not. They are ours nevertheless, because we act as co-causes of our own behaviors.
But here is the ethical difference: people like George want to be able to assign moral blame. Compatibilists, by contrast, simply think that when someone has engaged in an unethical behavior that is because his decision-making algorithms are not functioning properly. What we do then is not to "blame" them, and it is most certainly not to seek retribution or revenge against them. We first try to counter the negative effects of the unethical action in question, and second see if it is possible for the person who has been unethical to recover (or perhaps achieve for the first time) proper decision-making ability. In other words, we shift from a retributive to a rehabilitative system of justice.
If you read the above and find yourself thinking something along the lines of "well, then, if causal determinism is true why do I need to bother doing anything, since the outcomes are fated anyway?" you are engaging in what the ancient Stoics called the lazy argument. Let's say you get sick, and you think you don't need to see a doctor or take medicine, because you are either fated to die or to recover anyway. But how do you think you will recover, if you don't see the doctor and take the medicine? Again, you -- and your decision-making brain apparatus -- are part and parcel of the web of cause-effect, not something external to it and to which things just happen. If you get up and go to the doctor then you will get better. If you don't, you won't. You can't use determinism as an excuse for inaction.
We don't need the highly scientifically doubtful concepts of strong emergence and downward causation in order to work on fixing climate change, counter child trafficking, or fight a pandemic. We just need to reconcile the scientific and manifest images of those things and act on the basis of the best science and the most compassionate human values.