Neuroscience is vindicating the Marxist determinists

Nearly two hundred years later, scientists are still criticizing the idea of "free will".

Synapse by synapse, modern neurobiology is bringing us to the inevitable conclusion: Marx was right! The thought has struck me time and time again over the past few weeks as I’ve worked my way through the writing and lectures of Robert Sapolsky, a professor of neurology at Stanford University. Sapolsky’s research on topics like stress, depression, and nutrition has always been fascinating, but over the past few years his career has taken a remarkable turn: in interviews, a lecture series, and two books (one published and one forthcoming), he has become an active critic of the idea of “free will”. In this he has found himself at odds with many contemporary philosophers — but he also, I will argue, has significant support in certain readings of Marxist theory.

Neurological perspectives on free will have shifted significantly over the past decade. Beginning in the early eighties, research by Benjamin Libet seemed to demonstrate that electrical activity in the brain involved with carrying out deliberate action actually begins before we are conscious of our intent to do anything. This established an enduring logic for arguing against free will: if our “decision” to act takes place after the physical chain of causality appears in our brain, then the only question left is whether we can choose to “veto” that outcome en route, or whether we can somehow save something like “free will” by explaining these facts in a different way.¹

About ten years ago, however, studies by Aaron Schurger and Masayoshi Murakami called Libet’s research into question by suggesting that this pre-conscious brain activity is, in effect, just meaningless background static. This eventually led to a tidal wave of popular science articles about how free will has been saved from bad science. In a 2020 interview, neuroscientist Michael Egnor noted that Libet himself never thought that his research was at odds with the possibility of free will. He went on, however, to make some revealing comments about those who interpret the science differently:

Libet points out that his research unequivocally supports the reality of libertarian free will. But his experiments are described very often in the scientific literature and in the popular press as supportive of materialism…[sometimes], I have to say that maybe the misrepresentation is deliberate because it doesn’t support a materialist perspective.

Egnor, I would argue, is giving us a pretty good picture of the contemporary debate about the neuroscience of free will. Even today, Libet’s research still occupies a central place in it, as if this particular phenomena of preconscious brain activity will decide the entire question once we’ve understood it correctly. And even if we don’t take Egnor’s suspicions about motive seriously, the very fact that he voiced them reminds us that this debate still has a decidedly ideological valence. There are a whole range of nuanced and complicated philosophical positions one can take on Libet’s research, but Egnor is describing it the binary political terms that pit “libertarian free will” against “materialism”.

His description of “the popular press as supportive of materialism” is curious, meanwhile, since he cites as evidence the very articles I linked to above — the ones that herald free will’s triumph over bad science. But his suggestion about the scientific literature, I would say, is accurate. And so would Robert Sapolsky.

***

It would be impossible to provide an exhaustive account of all of the scientific research that explains, through ordinary physical mechanisms of cause-and-effect, various aspects of human behavior. Add up everything we know about physics, chemistry, evolutionary biology, anatomy, genetics, hormones, synapses, and so on and you can explain an astonishing amount of what we do. This is true of extremely simple behavior (like the patellar reflex), but it’s even proven true of extraordinarily complex behavior (like cheating on your significant other) that we used to think of as entirely volitional or simply random.

There is a very literal sense, in other words, that the scientific literature on human behavior has consistently affirmed the determinist position that Egnor associates with materialism. Instead of just looking at Libet, Robert Sapolsky thinks that we should take all of this research seriously — and that when we do, it builds a compelling case against antiquated ideas about free will.

To answer the basic question “Where did that behavior come from,” Sapolsky develops a standard, systematic approach, laid out in his Biology and Behavior coursebook:

We start off by studying the brain and the nervous system. Beginning to work back in time, we then try to understand further the things that modulate the nervous system, such as environmental triggers, hormones, and perinatal and fetal development. Then working further back, we look at the genetic attributes of the population that an individual comes from. This approach pushes us all the way back to examine what the pressures are of natural selection that sculpted that species.

Individually, the specific steps Sapolsky takes in this argument are rarely controversial. He will explain, for example, something about how noradrenaline binds with adrenergic receptors to produce entirely predictable responses within the sympathetic nervous system that can be explained at the level of chemical reactions. We all know that some of the things that the body does can be explained in this way and that volition has nothing to do with it; if you drink enough alcohol you are eventually going to pass out whether you want to or not.

What would be surprising would be if we were able to demonstrate that something about our behavior does not work this way.

The classic example of this kind of hypothesis came from Descartes, who imagined that the human pineal gland somehow (to simplify matters) transformed our spiritual energy into physical action. There is a reason why he said this, of course: even as Descartes famously argued that animals were just elaborate machines, he was trying to rescue some form of human free will from determinism. But as Sapolsky systematically lays out chains of causality from the level of molecular interaction all the way up to human behavior — even behavior that once seemed spontaneous — the cumulative effect is to place the full weight of science and our common sense notions of cause-and-effect against the existence of anything like a Cartesian pineal gland.

This point is easy to miss when we consider narrow questions independently. One can accept a purely mechanical description of how a neuron fires while leaving a kind of implicit space in his theory of behavior for some prior intervention by an uncaused “human agency”. Sapolsky, fortunately, avoids the trap so many determinists fall into of insisting on a mechanical explanation for components of human behavior that we all know are mechanical. And he also avoids fixing the whole debate on a single issue, like whether certain interpretations of Libet’s research are correct.

Instead, he focuses on how all kinds of known mechanisms of human behavior add up to an account that is exhaustive; presented over and over again with complete causal chains of chemistry and genes and hormones and nerves and muscle contractions, the reader is hard-pressed to pretend there is any explanatory space left for agency. For any given action, Sapolsky says,

Neurobiologists can go and find the neuron in your motor cortex which sent the signal to those muscles to flex. And you could find the neurons in what is called the pre-motor cortex which sent signals which triggered that motor cortex to send that signal. And you could then find neurons in the frontal cortex that, and find neurons in the prefrontal cortex that triggered that, and neurons in emotional parts of the brain that triggered those neurons…show me the neuron that started that cascade…for no prior causal antecedent reason…it’s just not there.

Ultimately, he insists, the most compelling explanations for human behavior are probably Darwinian. There is, of course, a grim history of frauds and monsters advancing all kinds ideas about this in Darwin’s name, usually by rationalizing aggression with “survival of the fittest” rhetoric or by floating entirely speculative stories about how this or that quirk of the human condition can be explained as an adaptation. The actual explanations that evolutionary biology provide for human behavior, it turns out, are often counterintuitive and causally remote.

Remember, for example, how you snapped at one of your coworkers the other day at the end of your shift?

Travel back in time more than a billion years, and you’ll find ancestors of the primitive unicellular organism Natronomonas pharaonis swimming around in the ocean. You’ll also notice something odd: a protein called rhodopsin is interfering with the chemical reaction that propels pharaonis through the water. Watch for a few days, and you’ll see that the interference isn’t random at all. When it’s exposed to orange light, rhodosin’s effect on the motor is more pronounced, to the point of completely reversing its rotation (and the direction that pharaonis is swimming in); when rhodosin is exposed to blue light, the motor works fine and actually speeds up.

Everything I’ve described so far is just an elaborate chemical reaction; I’m summarizing research by John and Elana Spudich, and if you like you can read the details here. But starting with this kind of basic physical mechanism one can build an airtight description of how human photoreceptors work, how they establish circadian rhythms within the suprachiasmatic nucleus (SCN), how neural pathways connect the SCN with the dorsal raphe nucleus (DRN), and how the DRN plays a major role in mood regulation. Which gives us a direct link between you not getting enough sunlight in your eyes a week ago, which disrupted your sleep cycle, and you snapping at your boss a few days ago because you were in a terrible mood.

Of course, much more went into that unfortunate episode with your coworker (I hoped you apologized!) than just a bad mood. Your circadian clock is just one gear, albeit an extremely important one, in the machine. And again, when I describe how any given part of the machine works, the temptation will be to say “Okay, that mood gear is mechanical — but there’s probably another gear, a free will gear, that my agency gets to control. And it was those wheels turning together that made my decision. I didn’t have to yell at her; I could have just stayed at home and caught up on my sleep!”

This is the temptation I described earlier: to insist that there must be something in the human brain that works very differently than everything else does, something like the Cartesian pineal gland and its magical spirits. This was a perfectly sensible idea back in the seventeenth century; and for those of us who don’t have a doctorate in neuroendocrinology, I think believing something like this is completely understandable today.

What Sapolsky shows us is that if you do decide you would like to learn more about the brain and the world it operates in, your intuition changes. You find mechanical descriptions for so much behavior — including behaviors that we never thought we’d be able to explain, like mood — that it starts to feel silly to fantasize that you’ll ever find anything else.

***

At this point this post has annoyed two groups of people. First, the overwhelming majority of professional philosophers who think that Robert Sapolsky is wrong — we’ll return to them eventually. And second, people who are still thinking about the very first sentence and asking themselves: what does any of this have to do with Marx?

To answer that, we should distinguish between two schools of Marxism. First, what I will call (to use an old term) the “indeterminists” — people who hold that historical materialism can facilitate some form of free will. This is the dominant understanding of Marx today, at least in the English-speaking world, and it has a perfectly respectable intellectual pedigree; Gramsci and Althusser, for example, were both indeterminists. There are all kinds of intellectual and rhetorical moves one can make to reconcile historical materialism with some form of human agency, but the typical one is to insist that while classes are bound by the laws of Marxist economics, individuals are not.

This group is not without its critics. The second school, determinist Marxism, holds that individuals do not have free will, perhaps (though not necessarily) as demonstrated by Marxist theory. Determinism was a common albeit controversial position in the 19th century — you can read people like Durkheim and Tolstoy wrestling with it, and the naturalists embracing it. In the 20th century, determinist Marxism was a common theme in communist and anti-communist rhetoric. Bukharin was probably its most influential champion, and since his position is so alien to the modern reader it’s worth quoting at length.

Having dedicated Historical Materialism: A System of Sociology to “expounding and developing” the laws of economics that emerge from Marxist theory, Bukharin, in Chapter 2, takes on the question directly:

If social phenomena follow a uniform law and if they are nevertheless the result of the actions of men, it follows that the actions of each individual also depend on something. It thus follows that man and his will are not free, but bound, being subject also to certain laws. If this were not the case, if each man and his will did not depend on anything, where would we get any regularity in social phenomena? There would be no such thing.

To appreciate how the Soviet determinists thought about this question, it’s worth noting that Bukharin is not advancing his position by trying to prove that it can be found in Marx. On the contrary, what he is doing is laying down a foundation of ideas that we must accept if we want to understand society scientifically. Which will eventually lead us to Marx, of course; but first, readers must be willing to think about the human condition rationally.

The doctrine of freedom of the will (indeterminism) is at bottom an attenuated form of a semi-religious view which explains nothing at all, contradicts all the facts of life, and constitutes an obstacle to scientific development.

Like Durkheim, Bukharin is trying to establish sociology as a science by insisting that the ordinary laws of cause and effect hold for social phenomena just like they do for everything else. But unlike Durkheim, he believed this meant accepting the hard truth that they govern individual behavior as well. And so he confronts us with the ruthless logic of determinism:

Man will fall in love when his organism has developed to that point. Man in a condition of extreme exhaustion surrenders to "black despair". In a word, man's feeling and will are dependent on the condition of his organism and on the circumstances in which on he finds himself. His will, like all the rest of nature, is conditioned by certain causes, and man does not constitute an exception to all the rest of the world: whether he desires to scratch his ear, or accomplish heroic deeds, all his actions have their causes. To be sure, in some cases these causes are very difficult to ascertain. But that is another matter. We have by no means succeeded in ascertaining all the causes in the domain of inanimate nature. But this does not mean that these things cannot be explained at all. We must bear in mind that, as we have seen, not only the "normal" cases are subject to the law of cause and effect. All phenomena are subject to this law.

Drawing a line between historical materialism and a man’s “desire to scratch his ear” may seem bold to the modern reader, but Bukharin’s ideas about determinism were pretty mild and conventional among Marxists and determinists alike. You could find Soviet intellectuals exploring positions that were far more radical elsewhere, especially in the (odd, and often profound) field of Marxist psychology. Here, for example, we find Volosinov taking aim at Freud:

The abstract biological person, biological individual — that which has become the alpha and omega of modern ideology — does not exist at all. It is an improper abstraction. Outside society and, consequently, outside objective socioeconomic conditions, there is no such thing as a human being.²

Modern indeterminists often characterize the ideological struggle between early Soviets and Western liberals as a struggle between a kind of unselfish collectivism and selfish individualism, but this is a simplification. Marxist determinists, even if they did not go as far as Volosinov, believed that accepting historical materialism and rejecting illusions about free will were part of the same scientific project. And this was no secret among Western liberals; particularly among the religious right, determinism was a favorite target among Marxism’s critics, who portrayed its critique of free will as dehumanizing, bizarre, and a justification for tyranny.

***

And so we come to Marx himself. Despite the endless volumes of writing on the mechanics of historical materialism (not just on determinism, but on for example the causative role of ideology), the reader will be in for a surprise if she looks to Marx himself for the same kind of concern. Most of the relevant debate focuses on his occasional references to the “laws” of economics and historical materialism; his famous “Men make their own history, but they do not make it as they please” line; and two larger passages, in particular the Preface to Contribution to the Critique of Political Economy, and to a lesser extent The German Ideology.

The indeterminists and the determinists read all of this quite differently, of course. My advice is that everyone is better off just reading the texts themselves, first because they are so short that it would be faster, and second because the exegesis is often very bad. Even in the scholarly literature among the indeterminists, for example, you can find Howard Sherman cleverly adding a key word in his paraphrase of Marx — “people freely make their own history” (emphasis added) — which then becomes evidence in his case that people make their own history freely.³ Just as often, you'll find textual evidence stretched beyond all plausibility: among the determinists, Bukharin supports his position that social phenomena is simply the aggregation of individual behavior by noting that

A certain order of social relations, wrote Marx, "is as much a product of human beings as is canvas, linen, etc."

That society is a “product” of humans does not really imply anything about whether it’s just an aggregate of their individual behavior, which is what Bukharin is using this quote to suggest, but this is the sort of rhetorical sillyness that the determinist/indeterminist Marxist debate often comes down to.

For what it’s worth, my reading of Marx is that he is conflicted about free will and determinism in an extremely common way that most people are, and that this results in him making contradictory statements that provide evidence for both sides. Consider this passage from his Critique of Political Economy:

In the social production of their life, men enter into definite relations that are indispensable and independent of their will, relations of production which correspond to a definite stage of development of their material productive forces...It is not the consciousness of men that determines their being, but, on the contrary, their social being that determines their consciousness.

If you must, you can make an elaborate argument about how when Marx said “their social being determines their consciousness” he actually meant something like “their consciousness determines their consciousness.” But I think the simpler and more defensible reading is just that Marx is pushing back against liberal ideas about agency. When on the other hand Marx writes that “The materialist doctrine concerning the changing of circumstances and upbringing forgets that circumstances are changed by men,” a determinist could always say that what this really means is…well, I don’t know how you make a determinist reading out of this.

This idea Marx as simply contradicting himself on determinism isn’t common, but I don’t think it’s particularly ambitious. Scholars and lay readers alike usually conclude that he’s inconsistent in other ways — for instance, in how he uses the term class — and even go so far as to distinguish between a “young Marx” who held one set of positions and an “old Marx” who held another. Meanwhile, in his excellent folk study Bound, Shaun Nichols explores the prospect that most people just “have blatantly inconsistent intuitions” about agency and sees a common source of the problem:

It is a deep fact about us that we are compulsive seekers of causal explanations…At the same time, people find it jarring and counterintuitive to think that their own choices are determined. (11)

That an economist who was often more interested in polemic than intellectual system-building should occasionally lapse into conflicting intuitions about agency should come as a surprise to no one; so if one wants to discover what the legendary True Marx thinks about this, he will first have to make up his own mind.

***

Now let’s turn to the first group of people who, by now, are probably furious: philosophers. Certainly they’re frustrated by the casual way I have been using terms like “free will” and “determinism” and “agency” — terms that, in the contemporary literature, often have precise technical definitions. Some who have ventured into the Marxist tradition, like Sherman, will simply not want to acknowledge that Marxist determinism ever existed. But more than anything, a lot of philosophers will be irritated that I’ve even given hard determinism the time of day. Most of them just don’t accept it: a PhilPapers Survey puts the number of philosophy faculty who reject free will at around 12%.

Instead, professional philosophers tend to arrive at two general conclusions that most readers will be familiar with. First there is the libertarian free will position, held by folks like Libet. Nearly 60% of philosophers, however, endorse a curious third position: what they call “compatibilism”, which effectively tries to reconcile the other two.

Robert Sapolsky has not publicly engaged with this literature in much detail — it will, evidently, be the subject of his upcoming book Determined: The Science of Life Without Free Will. But his general comments have been straightforward:

I’ve been forced to read all sorts of philosophers who write about free will, and it’s agony because I don’t understand what they’re saying…they’re terrible writers.

Sapolsky’s attitude towards philosophical literature on free will is not at all uncommon among scientists; physicist Sabine Hossenfelder, for example, dismisses libertarian arguments as “logically incoherent nonsense.”⁴ The determinist Marx, it turns out, sounds quite similar. In The German Ideology he repeatedly draws a sharp contrast between how philosophers think about human behavior and how scientists think about it:

Where speculation ends – in real life – there real, positive science begins…Empty talk about consciousness ceases, and real knowledge has to take its place. When reality is depicted, philosophy as an independent branch of knowledge loses its medium of existence.

Like Sapolsky and Hossenfelder, Marx’s specific objection to the philosophers is that they are engaged in “empty talk”:

The most recent of them have found the correct expression for their activity when they declare they are only fighting against “phrases.” They forget, however, that to these phrases they themselves are only opposing other phrases…It has not occurred to any one of these philosophers to inquire into the connection of German philosophy with German reality, the relation of their criticism to their own material surroundings.

And with their head in the clouds, the philosophers have erred on one question in particular: “consciousness, to which they attribute an independent existence”. This is wrong, the determinist Marx insists, because

The phantoms formed in the human brain are also, necessarily, sublimates of their material life-process, which is empirically verifiable and bound to material premises. Morality, religion, metaphysics, all the rest of ideology and their corresponding forms of consciousness, thus no longer retain the semblance of independence.

Marx and Bukharin are on the exact same page in Ideology: human behavior must be understood scientifically, and this “necessarily” means understanding it by identifying empirically verifiable causes.

And here we finally arrive at why I said that Marx was right: his specific attention to the human brain. He is not, in Ideology, making the indeterminist argument that individual behavior is outside the scope of historical materialism. He is not rolling his eyes at neurobiology as somehow irrelevant in the grand scheme of things. Marx, like Sapolsky, thinks that understanding human behavior demands an understanding of the human brain.

And Sapolsky, like Marx, thinks we also have to understand the rest of the world. Volosinov’s claim that the “biological individual…does not exist at all” may seem radical as stated; but it makes more sense, I think, when we read Sapolsky’s discussion of genetics in Behave and he arrives at his own “radical conclusion: it’s not meaningful to ask what a gene does, just what it does in a particular environment.” Whether we are talking about ego psychology agency or genetics, our descriptive accounts of human behavior start running into serious problems when we forget that these are just intellectual abstractions from the world of causes and effects that they are embedded in.

On the far horizon of research into human behavior, one can imagine points of evolutionary biology informing Marxist accounts of the economics — and vice versa. Something like this is already happening with the parallel field of game theory, which Sapolsky notes “originated in the area of economics.” In his lecture on “Cooperation, Competition, and Neuroeconomics,” he explains how evolutionary accounts of kin selection and population bottlenecks, combined with game theory tit-for-tat strategies, can explain how cooperation can emerge from the competitive dynamics of individual selection. One can see quite here quite clearly how social-scale economic logics and genetic behavior end up shaping each other — one might say, dialectically.

Remember the coworker you snapped at the other day? And when we traced it back to you being grumpy because you were experiencing circadian disregulation due to light-induced sleep problems, you pleaded that you could have simply chosen not to have gone into work? Here we see where Marx comes into the picture — because under capitalism, you cannot, of course, simply choose to not work. And in fact, Marxism also provides definite predictions about how your living conditions, under capitalism, are likely to deteriorate to the bear minimum needed to maintain productivity. Which means that of course you are going to be exhausted and grumpy. Yet another part of your life that, it turns out, is completely outside of your control.

Marx often made it quite clear that he imagined scientific progress moving precisely towards this sort of integrated account. “History itself is a real part of natural history – of nature developing into man,” he wrote in 1844. “Natural science will in time incorporate into itself the science of man, just as the science of man will incorporate into itself natural science: there will be one science.”

Perhaps in this expansive understanding of human behavior we will still find some room for individual free will. Still, I can’t help but wonder if Sapolsky and the determinist Marx are on their way to vindication — and I mean that quite literally. I can’t help but wonder.

1. Lavazza, Andrea. Free Will and Neuroscience: From Explaining Freedom Away to New Ways of Operationalizing and Measuring It. [link]

2. Valentin Voloshinov. Freudianism: A Marxist Critique.

3. Sherman’s paper also features a move that is, in my experience, far too common in indeterminist rhetoric:

Scientific Marxist determinism has always emphasized that human beliefs and actions must be included as a dynamic determining factor of social analysis. Certainly, humans are "free" in the sense that they may make any decision they care to make and may act upon it.

The reason I’ve dwelled so long on Marxists like Bukharin and Volosinov is that there is a real tendency, among indeterminists, to insist that the determinist position has never really existed. This, in turn, becomes evidence that determinist readings of Marx are unusual and therefore implausible. Suffice to say that even if you do not want to read the determinists, all you have to do is go back 70 years and read Marxists like Lukács complaining about the determinists to realize that folks like Sherman aren’t engaging with history.

4. I have to admit that I have the same impression as Sapolsky and Hossenfelder. Consider the standard “appeal to introspection” argument for free will, here given with unusual concision by Noam Chomsky:

We just can’t abandon believing it (free will); it’s our most immediate phenomenologically obvious impression, but we can’t explain it…If it’s something we know to be true and we don’t have any explanation for it, well, too bad for any explanatory possibilities.

This has always struck me as an exceptionally silly argument, first because philosophy and science have both always taken for granted that the world may not be as it appears — but more importantly, because even if our intuitions count as evidence, his rationale still fails. After all, as Nichols notes, free will is not the only position that we have strong intuitions about; the determinist position seems to be follow quite directly from our intuition that the world can be explained through physical causes and effects. I would in fact argue that the latter intuition is much stronger than the former. It’s not hard to imagine a world without free will; there’s a wealth of fiction and earnest philosophical writing which does just that. On the other hand, try as I might, I simply cannot imagine a world that isn’t ultimately determined by some law of physical cause-and-effect. It would simply be incoherent!