Why neuroscience is largely irrelevant to ethics

Benjamin Libet, neuroscientist

A few days ago, over at my other blog, I published an article that I touted on my social media as “the last piece on free will you will ever need to read.” That was a slight exaggeration, but only slight. The specific point of the post was to explain in some detail the ancient Stoic take on human decision making, what I and modern psychologists prefer to call volition rather than free will (given how loaded with metaphysical nonsense the latter term is). I also wanted to see how the Stoic position squares with the findings of modern science. As it turns out, that ancient view is highly compatible with what contemporary cognitive science says about the matter, but this is neither a miraculous coincidence nor indication that somehow the Stoics managed to anticipate scientific discoveries that would be made more than two millennia later. (Which would be just as preposterous as to maintain, as some do, that the pre-Socratic atomists “anticipated” modern physics. They didn’t, as even a superficial reading of the pre-Socratics, and a passing acquaintance with modern physics, should amply demonstrate.)

Rather, the reasons we still find so much of value in Stoic (or Aristotelian, or several other) ancient moral philosophy are twofold: first, some of the ancients were keen observers of human psychology; second, moral discourse has little to do with whatever mechanisms make it possible for human brains to think about morality (so long as some mechanisms that allow us to think do exist, of course). Both notions need to be unpacked a bit, which is what I intend to do in this essay.

What was so special about Aristotle, or Epicurus, or Epictetus? In a sense, not much. They were sharp thinkers who paid attention to the empirical side of what they were thinking about. We tend to forget that many others at the time and since have written about the same topics, and yet they are completely forgotten, or they appear at best as footnotes in philosophy books. (Have you ever heard of Aristippus of Cyrene? Not likely, and he was one of the major figures among the minor Greek philosophers…)

The reasons we read some ancient philosophers are, so to speak, evolutionary. Specifically, the cultural analogues of two basic processes that steer biological evolution: drift and selection. Drift is about statistical sampling: some books survive and others don’t because of luck. There probably never were too many copies — by modern standards — of the works of Chrysippus, one of the most noted Hellenistic philosophers, and unfortunately not a single one has come down to us. Selection makes it so that whatever authors are highly esteemed not just by their contemporaries, but further and further down in history, are the ones whose works and ideas tend to survive. In the case of Chrysippus, we know a good amount about what he thought because so many later commentators copied several of his passages, in order to praise him or criticize him. To put it into another fashion, we still read Plato and Aristotle because of what biologist Jacque Monod once called a combination of chance and necessity.

But we don’t read all of Plato and Aristotle nowadays, unless we are historians of philosophy, or of science. There isn’t much point in consulting Aristotle’s Physics if you are a physicist, because the field has moved very far from the Aristotelian positions, beginning with Galileo and arriving at Einstein and Stephen Hawking. By contrast, philosophers still find a lot of value in the Nichomachean Ethics. Ill informed people (who shall here go unmentioned) are under the impression that this is because philosophy, unlike physics, doesn’t make progress (usually, these people just happen to be physicists). But that’s sheer ignorance, which ought (morally) to be embarrassing. Philosophy does make progress (see here), but it is a very different kind of endeavor from physics, so any direct comparison is a category mistake.

No, the reason Aristotle, the Stoics, and so forth are relevant today (other than the above mentioned one that they were la creme de la creme of their period) is that modern science has little of relevance to say about certain branches of philosophy, and in particular ethics. (Yes, I know, certain individuals are making a cottage industry of arguing the opposite. But they too shall go mercifully unmentioned in this post. I’ve dealt with them ad nauseam in the past.)

The reason this is the case has been explained by philosophers Ludwig Wittgenstein and Wilfrid Sellars, and is exemplified by the work of neuroscientist Benjamin Libet. Let me explain.

First, Wittgenstein. In Tractatus 4.111 he famously wrote that “philosophy is not one of the natural sciences,” adding at 4.112 that “philosophy aims at the logical clarification of thoughts.” In the Philosophical Investigations we find:

“[Philosophy’s] investigation is a grammatical one. Such an investigation sheds light on our problem by clearing misunderstandings away. Misunderstandings concerning the use of words, caused, among other things, by certain analogies between the forms of expression in different regions of language.” (90)

While I think that Wittgenstein had too narrow a view of what philosophy does, there is quite a bit of truth in the above. The job of philosophers isn’t to discover new things about the world (we’ve got science for that), but rather to clarify issues by way of critical analysis, and to see how things that appear disparate “hang together,” so to speak. That is, for instance, why metaphysics isn’t being replaced by physics, it is transforming itself into a discipline informed by physics (and biology, and other sciences) whose objective is to make sense of the picture of the world that emerges from the discoveries of individual special sciences, something that no single science does or is concerned with. (See, for instance, Ladyman and Ross’ Every Thing Must Go, a sort of manifesto for a naturalistic metaphysics.)

Wittgenstein becomes even more relevant to the present discussion when we consider his concept of “language games” as presented in the Investigations:

“The language is meant to serve for communication between a builder A and an assistant B. A is building with building-stones: there are blocks, pillars, slabs and beams. B has to pass the stones, in the order in which A needs them. For this purpose they use a language consisting of the words ‘block,’ ‘pillar,’ ‘slab,’ ‘beam.’ A calls them out; B brings the stone which he has learnt to bring at such-and-such a call. Conceive this as a complete primitive language.” (2)

Ethics is another language game, or, rather, a multiplicity of language games, since there are a number of ways to conceive, talk about, and actually do, ethics. Within the human community, we talk about “good,” “bad,” “moral,” “immoral,” “ought,” and so forth, and any competent language user understands what others mean by those words. Moreover, .just like the words of the builder’s language actually help building things, so the words of ethical language actually help regulate our actions within a given community. The fact that science comes in and, say, tells us that “bricks” are really mostly empty space is interesting from within the science language game, but it is utterly useless, and indeed a distraction, to the builder. Analogously, that a neuroscientist may be able to tell us which parts of the human brain are involved in the production of ethical judgments, and by which cellular means, is interesting within the language game of neuroscience, but it is a useless distraction if we are concerned with improving social justice, or becoming a better person.

Which brings me to what I have termed the most important philosopher you likely never heard of: Wilfrid Sellars. My friend Dan Kaufman and I did an extensive video conversation on Sellars, which I think is worth checking out. One of Sellars’ landmark ideas was the distinction between what he called the manifest and the scientific images of the world. The manifest image is the way most people understand and navigate the world. The Sun “rises,” genocide is morally repellant. That sort of thing. The scientific image, by contrast, is the way science looks at the world: the Sun does not, actually, rise; it is the Earth that rotates on its axis. As for genocide? Ah, therein lies the rub. I’m sure there are scientific explanations for why genocide is such a recurring feature of human history, from the biology and neuroscience of violence to those of inter-group relations. While such scientific understanding of genocide may be useful, it does not give us the complete picture. Why not?

Because, according to Sellars, the manifest, but not the scientific, image deals with things like reasons and values. This is not a call to reject science. On the contrary. Sellars was quite clear that whenever the scientific and the manifest images of the world are in conflict (as in “the Sun rises” vs “the Earth rotates” case), then the sensible thing is for us to yield to science. But science simply isn’t in the business of doing a number of other things for which we have developed different tools: philosophy, literature, history, and so forth. These tools are complementary with, not opposed to, scientific ones. Ideally, says Sellars, we want to develop a conceptual stereoscopic vision, whereby we are capable of integrating the manifest and scientific images. Indeed, according to Sellars — and I wholeheartedly agree — developing and constantly updating such vision is a major task of philosophy, and our discipline is uniquely positioned to carry the task out because of both its methods (empirically-informed critical discourse) and its scope (very, very broad).

In a sense, what emerges from Wittgenstein, but even more so from Sellars’ thought is that there are a number of things about which we can talk at different levels of analysis, and which level(s) make the most sense depends on what it is that we wish to accomplish. While in theory a full integration of all levels may be possible, in practice it is often not desirable, because it doesn’t help with the particular language game we happen to be playing.

Let me then come back to “free will” (or volition), and use my discussion of Stoic philosophy as it compares to the famous experiments by Benjamin Libet to present a specific example of what I have outlined above, attempting to convince you of why I think science is largely irrelevant to moral discourse.

The Stoics thought that we have a faculty of judgment, which they call the hêgemonikon. It was a major goal of Stoic training to improve the way we use it, i.e., to arrive at better and better judgments about whatever life throws at us. In the post at my other blog I suggest that, roughly speaking, the hêgemonikon corresponds to the frontal lobes of the human brain, which are far more developed than in most other mammals, and are known to be associated, in fact, with our capacity for judgment, and in particular with our ability to “veto,” so to speak, certain actions that might otherwise come natural to us (as in: “there is a strange noise in my house in the middle of the night! Someone is about to kill me!! I need to run the hell out of here!!! … Oh, wait, it’s the cat. Back to sleep).

The Stoics themselves were spectacularly wrong about the likely location of the hêgemonikon: they thought it resided in the heart. But pretty much everything else they said about its functioning and how we can improve it was right on the money, as shown by the fact that 23 centuries later Stoic “psychology” still informs a number of evidence based psychotherapies, such as rational emotive behavior therapy and cognitive behavioral therapy.

How is this possible? Because most of what the Stoics thought about the hêgemonikon was part of the manifest image, and was useful then as it is now for the simple reason that people still deal with the same basic issues: unhealthy emotions like anger and fear, and the search for better ways to relate to others and improve the human polis. What the Stoics got wrong, not at all surprisingly, is the bit that belongs to the scientific image: as it turns out, our faculty of judgment depends on a particular part of the brain, not the heart. Crucially, though, this has had no effect whatsoever on Stoic philosophy or its usefulness. A modern Stoic simply updates that bit of information, thanks the scientist, and goes back to her practice.

Nowadays, whenever the topic of human volition comes up someone is bound to cite the famous experiments carried out by Benjamin Libet, beginning in 1983. Briefly, he asked subjects to follow the movements of a dot on the screen of an oscilloscope. The dot moved like the hands of a clock, but faster. Libet told his subjects to move a finger at a moment of their choice during the experiment, noting the position of the dot when they became aware of their decision to act. The experiment showed that the decision to move the finger entered conscious awareness about 200 milliseconds before the actual movement. But, stunningly, there was a rise in the so-called “readiness potential,” which is thought to be associated with the preparation for action, about 550 milliseconds before movement. So the subjects appeared to get ready to move the finger a full 350 milliseconds before they became conscious of their decision to do so. (Indeed, in later experiments, the readiness potential has been shown to build up even as long as 1.5 seconds before movement.)

Taken at face value, Libet’s results seem to show that we decide our actions unconsciously, and that what we call consciousness is simply a (late) awareness of a decision that has been made. There are several well known criticisms of such conclusion, beginning with the obvious one, that the experimental conditions have precious little to do with the recursive, complex behavior that we normally label “conscious decision making,” and which is understood as a continuous feedback loop between what Daniel Kahneman calls System I (fast, subconscious) and System II (slow, deliberate) brain processing systems. Moreover, recent research has both amply confirmed, and yet significantly re-interpreted, Libet’s original findings.

But a good reason to think that Libet’s experiments do not mean what so many enthusiasts of the “free will is an illusion” bandwagon seem to think they mean, is Libet’s own commentary:

“The finding that the volitional process is initiated unconsciously leads to the question: is there then any role for conscious will in the performance of a voluntary act? The conscious will does appear 150 msec before the motor act, even though it follows the onset of the cerebral action by at least 400 msec. That allows it, potentially, to affect or control the final outcome of the volitional process. An interval msec before a muscle is activated is the time for the primary motor cortex to activate the spinal motor nerve cells, and through them, the muscles. During this final 50 msec, the act goes to completion with no possibility of its being stopped by the rest of the cerebral cortex. The conscious will could decide to allow the volitional process to go to completion, resulting in the motor act itself. Or, the conscious will could block or ‘veto’ the process, so that no motor act occurs.” (B. Libet, Mind Time: The Temporal Factor in Consciousness, 2004, p. 137)

[Once more, to preempt distracting discussions: I do not think we should talk about “free will,” which is a hopelessly metaphysically confused concept. We are talking about what psychologists themselves call volition, i.e., the ability of human beings to make complex decisions informed by conscious thought. Hopefully no one will deny that we do have such ability.]

Interestingly, studies have found very good experimental evidence for the veto power Libet is talking about. But that is “interesting” from within the language game of neuroscience. It makes no difference at all in terms of the language game in which the Stoics — and most of us — are engaged, that of improving ourselves as individuals and of making society a better place for everyone to live.

That is why, as a scientist, I will keep following with interest the undoubtedly fascinating future developments of cognitive and neuro-science. But it is also why, as a philosopher and human being, I’m not very concerned with how those findings will impact my day to day life in the realm of ethics. As the Stoic philosopher Epictetus aptly put it:

“You are not flesh or hair but volition; if you keep that beautiful, then you will be beautiful.” (Discourses III.1.40)