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Does Neuroscience Refute Free Will?

Tags Philosophy and MethodologyPraxeology


This is the excellent foppery of the world, that, when we are sick in fortune, — often the surfeit of our own behavior, — we make guilty of our disasters the sun, the moon, and the stars; as if we were villains on necessity, fools by heavenly compulsion, knaves, thieves, and treachers by spherical predominance, drunkards, liars, and adulterers by an enforc'd obedience of planetary influence, and all that we are evil in, by a divine thrusting on. —William Shakespeare

In the above quote from King Lear we find a description of those who, throughout human history, deny free will and personal responsibility, instead blaming their wrongdoings on interventions divine and planetary. In a recent article, Joshua Greene and Jonathan Cohen join the believers in the "divine thrusting on."1 This being the scientific age, and our authors being card-carrying neuroscientists, the divine thrusting on becomes a neuroscientific thrusting on, the brain playing the role of the stars above.

The divine thrust of their argument is that we have no free will because there is neuroscience, though our laws have yet to take this into account:

… the law's intuitive support is ultimately grounded in a metaphysically overambitious, libertarian notion of free will that is threatened by determinism and, more pointedly, by forthcoming cognitive neuroscience…. The net effect of this influx of scientific information will be a rejection of free will as it is ordinarily conceived, with important ramifications for the law.2

What are these ramifications? To begin with, the concept of personal responsibility is obsolete. Since all actions are determined by the "preexisting state of the universe," we have no choice in the matter. As they put it: "Given a set of prior conditions in the universe and a set of physical laws that completely govern the way the universe evolves, there is only one way that things can actually proceed." Thus we can logically trace everything back to the Big Bang that blasted the universe into existence. Should you ask why I had bagels rather than bananas for breakfast this morning, for example, I can refer you to the Big Bang theory of human action.

But if there is already the Big Bang, why do we need neuroscience to reveal our lack of free will? According to Greene and Cohen, for ages "scientific" philosophers, i.e. philosophers of their determinist camp, had argued against free will, but because the mind was then a black box, it was easy for the deluded religious people, the soft humanists, and other dim-witted souls to cling to the illusion of free will.

Now that we have neuroscience, however, the mind is a black box no more — it is high time for the rest of us to wake up from our dogmatic slumber and smell the deterministic universe. In short, while the Big Bang provides the big picture, neuroscience supplies the details, which will make it abundantly clear, even to the lay public, that we are literally puppets in a deterministic universe after all.

Blame it on the brain

Greene and Cohen argue that our brains are responsible for all our behaviors. Our "brains" commit crimes. "We" are innocent. Thus, in their words, "demonstrating that there is a brain basis for adolescents' misdeeds allows us to blame adolescents' brains instead of the adolescents themselves." It is fortunate that the boys in the neighborhood have not read their article, for here is their new defense after damaging your property: I didn't do it, it was my brain!

Although it has been known even before Plato that the brain plays a central role in behavior, this particular argument is rather novel. One reason others have not been bold enough to advance it (despite a perennially strong demand for determinism) is that it contains a glaring category error. Greene and Cohen compare two opposing sources of agency — either your brain or you — as if they are mutually exclusive, as if without your brain you would still be a moral agent.

As a result of this error, Greene and Cohen conclude, "the idea of distinguishing the truly, deeply guilty from those who are merely victims of neuronal circumstances will, we submit, seem pointless."

But the moral agent in the legal sense is the whole package — you consisting of your brain and the rest. To say that we are victims of neuronal circumstances is to say that we are victims of ourselves. The underlying assumption is that we have no control over "neuronal circumstances," just as we have no control over "external circumstances." But this assumption (a newly bottled behaviorist assumption) entirely contradicts our knowledge that the brain is a self-organizing and self-regulating biological system, not merely a step in the transformation of some external stimulus to behavioral output.

It is, however, not necessary to discuss in any detail the brain as a control system in order to refute Greene and Cohen, for their argument is not based on any understanding of the brain at all. It boils down to the primitive logic that, for example, if I stole your wallet then my hand is to be chopped off.

Mr. Puppet

To their credit, Greene and Cohen sensed that blaming everything on the brain is not enough. They have another weapon in store for free will, yet another "thought experiment." For their strategy is to generate as many arguments as they can against free will, hoping that some of them will have done the damage, even if these arguments contradict each other.

In their second strike, they urge us to imagine the case of a "Mr. Puppet," a criminal designed by a group of scientists through tight genetic and environmental control. During Mr. Puppet's trial, the lead scientist is called to the stand by the defense. And here is what Greene and Cohen had him say:

I designed him. I carefully selected every gene in his body and carefully scripted every significant event in his life so that he would become precisely what he is today. I selected his mother knowing that she would let him cry for hours and hours before picking him up. I carefully selected each of his relatives, teachers, friends,enemies, etc., and told them exactly what to say to him and how to treat him. Things generally went as planned, but not always. For example, the angry letters written to his dead father were not supposed to appear until he was fourteen, but by the end of his thirteenth year he had already written four of them. In retrospect I think this was because of a handful of substitution I made to his eighth chromosome.

Of course, a change in the chromosome cannot determine the timing of a nasty letter written, since the genome does not contain information that specifies any of our actions. The environmental regulation, too, is impossible, except in science fiction. But plausibility or knowledge of basic biology is not to be expected from our authors. Greene and Cohen believe that Mr. Puppet is not responsible for his actions, because "forces beyond his control played a dominant role in causing him to commit the crimes, it is hard to think of him as anything more than a pawn."

But even if we assume, for the sake of argument, that such a person could be so designed, we might conclude that he is indeed a puppet of the scientist-designer, while we are not puppets of this sort. Our genes are not selected, nor our environment scripted, by anyone.

Not surprisingly, however, Greene and Cohen reach a rather different conclusion:

What is the difference between Mr. Puppet and anyone else accused of a crime? After all, we have little reason to doubt that (i) the state of the universe 10,000 years ago, (ii) the laws of physics, and (iii) the outcomes of random quantum mechanical events are together sufficient to determine everything that happens nowadays, including our own actions. These things are all clearly beyond our control. So what is the real difference between us and Mr. Puppet? … in a very real sense, we are all puppets. The combined effects of genes and environment determine all of our actions. Mr. Puppet is exceptional only in that the intentions of other humans lie behind his genes and environment. But, so long as his genes and environment are intrinsically comparable to those of ordinary people, this does not really matter. We are no more free than he is.

In an apparent slip, they acknowledged that the scientists had intentions, that they deliberately acted in designing Mr. Puppet. Their actions apparently differ from causes that are not human actions. Greene and Cohen never bothered to ask whether these scientists ought to be punished for specifically designed someone to commit crimes, whether they are responsible at all. But if we are forced to accept this scenario, then the responsibility for the crimes appears to lie with the scientists — for designing puppet criminals.

According to Green and Cohen, however, Mr. Puppet's genes and environment are "intrinsically comparable" to those of ordinary people, as if we all live in a designed environment, in which people deliberately abuse us and lie to us; as if our genes, rather than the results of natural selection, are picked by a team of evil scientists. Intrinsically comparable? By that they presumably mean that the environment is still a earthly environment like ours, the same house with furniture and TV and parents, and so on, and the genes are still stretches of DNA made up of garden-variety nucleotides.

But clearly these "intrinsic" features are irrelevant in Mr. Puppet's case. His genes and environment, after all, are designed to make him a criminal. But note, in particular, Greene and Cohen's peculiar emphasis on the combination of genes and environment. Biology, of courses, tells us there are additional factors which are neither genetic nor environmental, but we can safely assume that these authors, possessing no particular interest in the science of biology, are not aware of these.

Being metaphorical scientists, by "genes and environment" they mean everything that makes us who we are, everything that determines our actions. We are now ready to translate their claim into plain English: Everything that determines who we are determines who we are; everything that determines our actions determines our actions. Surely we do not have control over everything — Greene and Cohen correctly assume. And surely all possible factors combined determine our actions. But while reaching such a brilliant conclusion they have spun their minds out of control, ignoring the circularity in the process. We are compelled by the laws of logic to agree with them: Yes, a banana is a banana.

Illusion of free will

Having thus disposed of free will, Greene and Cohen are ready to explain why we think we have such a thing. If we think we have something that doesn't exist, then that something must be an illusion. Hence their claim that the brain generates the illusion of free will to fool us into thinking we are in control.

With becoming modesty, our authors compare themselves to Copernicus, Darwin, and Freud in overthrowing human narcissism. Copernicus removes the earth as the center of the universe, Darwin removes human beings as lords of the earth, and Freud removes consciousness as the sole determinant of human behavior. Here comes another blow beneath the belt — even what little conscious control you have over your action is an illusion.

It seems to me, however, that this is a case of sadomasochism. Green and Cohen appear to derive keen delight out of wounding human narcissism, as represented by free-will folk psychology. You thought you decided to read this article because it seemed interesting. But no, you have no clue, and that thought was really just some illusion generated by your brain to mask its cluelessness.

How much insult to your narcissism can you take? That is the question, on which your scientistic manhood depends. Only tough scientists like Greene and Cohen are brave enough to take determinism straight, without illusions. And if you don't think you are a puppet yet, they will beat you into submission with their thought experiments and imagined data until you give up your selfhood. And so the game goes on.

Although I do not wish to deny the multitudinous pleasures derived by Greene and Cohen from becoming puppets of metaphysical fiction and mouthpieces of pseudoscientific rant, I do wish to examine the evidence they present for their claims.

For such evidence Greene and Cohen rely on the work of Daniel Wegner,3 a Harvard psychologist and a fellow metaphorical scientist. According to Wegner, our actions are not caused by our willing. In support of this claim he cites evidence that hypnosis or brain damage can impair our sense of free will, that various experimental manipulations can create in us the illusion of control.

Our immediate response is: So what? We will not have free will if our heads are cut off. We will not have free will if we are asleep. Sometimes we erroneously thought we caused something to occur when, in fact, we did not. From this, however, it does not follow that free will is an illusion.

Under hypnosis, for example, we might feel that our arm was raised even though we did not will it. Likewise, when our motor cortex or our muscle is stimulated, various movements might be induced which are not willed. For Wegner, however, this sense of "it just happens" is a more accurate description of what really happens when we act. It never occurred to him that there is no experience of will because these are not instances of voluntary actions under our control.

Wegner very much prefers this sense of passivity, for only then do we feel like inanimate objects. When my arm uncontrollably does something, it is acting as a "scientific object" should, like a brick. Our free will must be an illusion because it does not fit into Wegner's scientific understanding of the world.

The philosopher Daniel Dennett believes that, for the sake of convenience, we adopt the "intentional stance" when interpreting the behavior of other human beings. Wegner's position can be described as the "passivity stance." He prefers to feel like the hypnotic subject, the brain damaged patient, or a zombie in general, because, according to his scientific Weltanschauung, the passivity stance is a more accurate reflection of reality. But the question remains as to whether Wegner, or the average man on the street, is actually delusional.

Agreeing with Wegner's claim that our sense of free will is an illusion, Greene and Cohen go one step further, and argue that our attribution of free will in others is also an illusion.

They cite a study by Heberlein et al., who presented the following film to human subjects: a big triangle chases a little circle around the screen, bumping into it. The little circle repeatedly moves away, and a little triangle repeatedly moves in between the circle and the big triangle. When normal people watch this movie they see these interactions in social and intentional terms. The big triangle tries to harm the little circle, and the little triangle tries to protect the little circle.

However, a patient with damage to the amygdala, an almond-shaped collection of different brain structures, fails to see these shapes in such intentional terms.4Consequently, for Greene and Cohen, because this attribution of free will is generated by a brain area, it is also an illusion.

Readers of my earlier article will be familiar with Greene and Cohen's penchant for evolutionary speculation. Here they go again. According to their new so-so story, parts of the brain, in the course of evolution, become specialized modules for folk psychology, e.g. attributing free will to others; other parts, for folk physics, e.g. believing in the sort of motion typically seen in a Disney cartoon. We know that folk physics is wrong, but folk psychology is just as wrong, according to Greene and Cohen. Because of our folk psychology system, we think of other animate objects as uncaused causers. But after learning neuroscience, "when we look at people as physical systems, we cannot see them as any more blameworthy or praiseworthy than bricks."

Perhaps we could posit, in addition to the folk physics system and the folk psychology system, a third system of masochistic scientism, which fools one into believing one is a brick being acted on by the forces of nature, rather than an acting agent responsible for his actions. The neural basis of this third system, I submit, remains to be established.

To summarize then, our brick-minded theorists accuse folk psychology behind the law to view moral agents as uncaused causers. Since we are not uncaused causers, we cannot be moral agents, and we cannot be responsible for our actions.

Now if I am an uncaused causer, my actions are insulated from any external influence. Suppose a man is given a life sentence for killing the guard while robbing a bank, such a punishment cannot possibly prevent me from doing the same. Deterrence is indeed impossible if I am the uncaused causer of my actions.

However, this cannot possibly be the assumption behind our law, because it cannot possibly explain the law's focus on intentionality. According to the folk psychology that Greene and Cohen attack relentlessly, it is characteristically human that we deliberately choose appropriate means to reach desired ends. This capacity enables us to become moral agents, the targets of praise or blame. For example, an act is not guilty lest there be a guilty mind (Reum non facit nisi mens rea).

As Mises repeatedly pointed out, the very concept of human action, of means and ends, presupposes the category of causality. Responsibility does not imply that we are unmoved movers in the Aristotelian sense, standing outside of the chain of cause and effect, but that we, as agents of intentional actions, are in a peculiar position in a long chain of causes stretching back to the Big Bang. We are agents capable of controlling our actions, not reflex-arcs translating stimulus into response.

The law, then punishes crimes that are the result of deliberation and willing, and is lenient towards accidents or those agents incapable of rational actions (e.g. children). This selectivity can only be based on the idea of deterrence. For it would be absurd to tell someone not to murder, if he could not help it, just as it is absurd to tell someone to stop beating his heart.

The law, instead, punishes crimes that result from actions that we can control, and could thus prevent such actions in the future.

If the law is in fact based on the assumption of uncaused causers, it would have no reason to make distinctions between deliberate murdering and accidental killing. Strict liability would apply to all crimes. It is of course beyond the scope of this article to discuss the history of the law, though it should be pointed out that the concept of personal responsibility in violent crimes is in fact a relatively recent development. Strict liability, extending to relatives and Lords, is common in many primitive societies (I refer the interested reader to Pollack and Maitland's masterpiece or Zane's book on the history of law).

Law and liberty

Free will, in the sense discussed here, means that humans control what they do. Neuroscience will not change this fact. Science fiction, of the variety favored by Greene and Cohen, could always imagine such a day. In this sense, it cannot be distinguished from any teleological religion.

Indeed, determinism of this type, which claims that human beings do not choose, do not act, but are always acted upon, has been revived innumerable times in history, in various guises. It is a historical fact that primitive savages, religious fanatics, and believers in inexorable laws of history have always advocated some version of it.

In the development of the law also, the concept of personal responsibility evolved, partly because some human beings, after struggling free from superstition and the "passive stance," began to understand the nature of their own actions and their effects on the world. Enlightened individualism, we should remember, was a late development, and remains unpopular in many parts of the world today. The intuitive folk psychology of human action we possess is the product of such enlightenment.

On the other hand, in attacking the concept of free will and personal responsibility, Green and Cohen merely revive the cult of irrational thought that has long prevailed in human societies. It should not therefore surprise us to find in their article the following sentence: "rationality is just a presumed correlate of what most people really care about." Indeed, what is left of rationality when you are not responsible for your actions?

In place of reason, these authors substitute aggregate welfare. The law reformed in light of neuroscientific knowledge should, according to them, aim to promote future welfare, rather than punish those responsible for their crimes. In an earlier article I discussed the attempt by these authors to abolish universal moral norms using brain imaging data, in the name of aggregate welfare. We should at least applaud their consistency. Of course, a universal moral norm such as the Categorical Imperative would have no meaning if there is no free will. Why tell someone not to steal if he could not help it, if his brain was to blame?

All considered, then, their arguments boil down to this: (1) the criminal is not responsible for his crime because everything that determines who he is determines who he is; (2) instead of punishing criminals for what they deserve, the law should maximize future welfare.

Ethically, it seems preposterous to argue against the total welfare of mankind, just as logically, it is impossible to refute a tautology. The take-home lesson here is that you should always watch out for someone who argues for something that cannot possibly be contradicted, for there is often a hidden agenda, attached to the can't-possibly-be-wrong package, that triggers the self-destruction of the whole thing once uncovered.

As I pointed out in the earlier article, their concept of aggregate welfare is a vacuous concept, made up for the sake of convenience. We cannot possibly calculate what this welfare is, though we can indirectly observe, by studying history, the long-term effects of certain rules and practices on groups that follow them. In the latter, somewhat more concrete sense of welfare, our current legal framework appears to have been one of the chief promoters of human welfare, judging by the remarkable spread of the relevant ideas from the West, against often strong resistance from local customs and primitive practices.

Finally, throughout their essay, Greene and Cohen emphasize that the "libertarian" conception of free will which they attack has no connection to the political philosophy. This disclaimer, however, betrays ignorance of the political philosophy. Free will and responsibility provide the necessary foundation of the libertarian political philosophy. Laws protect liberty, and liberty entails responsibility.

Their arguments for determinism are yet another attempt to abolish laws as abstract rules that apply to everyone equally. Instead the State and its "scientific experts" will get to decide whether a person will be harmful to society or not, in order to maximize future welfare in each case (i.e. to do whatever those in power wish to do). The law itself becomes meaningless. And instead of being general rules that protect individual liberty, in the hands of Greene and Cohen, and in the name of neuroscience, it will be used, as a tool for state intervention and arbitrary judgments, to destroy liberty.

  • 1. Greene, J. & Cohen, J. "For the law, neuroscience changes nothing and everything." Philos Trans R Soc Lond B Biol Sci 359, 1775-85 (2004).
  • 2. von Mises, L. Theory and History (Mises Institute, 1957).
  • 3. Wegner, D. M. Precis of the illusion of conscious will. Behav Brain Sci 27, 649-59; discussion 659-92 (2004).
  • 4. Heberlein, A. S. & Adolphs, R. Impaired spontaneous anthropomorphizing despite intact perception and social knowledge. Proc Natl Acad Sci U S A 101, 7487-91 (2004).

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Lucretius is a neurobiologist living in Maryland.

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