Guest Post: Tom Levenson on the Iraq War Suicides and the Material Basis of Consciousness

By Sean Carroll | June 4, 2008 6:50 pm

For his second guest post, Tom follows in our proud tradition of fearless eclecticism,
mixing neuroscience and current events with a bit of materialistic philosophizing. His first post was here, and his third is here.


Burrowing into tragedy: a story behind the story of the Iraq War Suicides.

My thanks to all here who gave me such a warm welcome on Monday (and, again, to Sean for asking me here in the first place).

This post emerges out of this sad story of a week or so ago.

Over Memorial Day weekend this year there was a flurry of media coverage about the devastating psychological toll of the Iraq and Afghanistan wars. The single most awful paragraph in the round-up:

“According to the Army, more than 2,000 active-duty soldiers attempted suicide or suffered serious self-inflicted injuries in 2007, compared to fewer than 500 such cases in 2002, the year before the United States invaded Iraq. A recent study by the nonprofit Rand Corp. found that 300,000 of the nearly 1.7 million soldiers who’ve served in Iraq or Afghanistan suffer from PTSD or a major mental illness, conditions that are worsened by lengthy deployments and, if left untreated, can lead to suicide.”

(For details and a link to a PDF of the Army report – go here.)

This report, obviously, is the simply the quantitative background to a surfeit of individual tragedy – but my point here is not that war produces terrible consequences.

Rather, the accounts of the Iraq War suicides — 115 current or former servicemen and women in 2007 – struck me for what was implied, but as far as I could find, not discussed in the mass media: the subtle and almost surreptitious way in which the brain-mind dichotomy is breaking down, both as science and as popular culture.

How so? It is, thankfully, becoming much more broadly understood within the military and beyond that “shell shock” is not malingering, or evidence of an essential weakness of moral fiber. PTSD is now understood as a disease, and as one that involves physical changes in the brain.

The cause and effect chain between the sight of horror and feelings of despair cannot, given this knowledge, omit the crucial link of the material substrate in which the altered and destructive emotions can emerge. PTSD becomes thus a medical, and not a spiritual pathology.

(This idea still faces some resistance, certainly. I launched my blog with a discussion of the attempt to court martial a soldier for the circumstances surrounding her suicide attempt. But even so, the Army is vastly further along in this area that it was in the Vietnam era and before.)

Similarly, depression is clearly understood as a disease with a physical pathology that underlies the malign sadness of the condition. (H/t the biologist Louis Wolpert for the term and his somewhat oddly detached but fascinating memoir of depression.)

This notion of the material basis of things we experience as our mental selves is not just confined to pathology. So-called smart drugs let us know how chemically malleable our selves can be.

More broadly, the study of neuroplasticity provides a physiological basis for the common sense notion that experience changes who we perceive ourselves to be.

All this seems to me to be a good thing, in the sense that (a) the study of the brain is yielding significant results that now or will soon greatly advance human well being; and (b) that the public seems to be taking on board some of the essential messages. The abuses (overmedication, anyone?) are certainly there. But to me, it is an unalloyed good thing that we have left the age of shell shock mostly behind us.

At the same time, I’m a bit surprised that the implications of this increasingly public expression of an essentially materialist view of mind haven’t flared up as a major battle in the science culture wars.

Just to rehearse the obvious: the problem with cosmology for the other side in the culture war is that it conflicts with the idea of the omnipresent omnipotence of God. The embarrassment of evolutionary biology is that it denies humankind a special place in that God’s creation, destroying the unique status of the human species as distinct from all the rest of the living world.

Now along comes neuroscience to make the powerful case that our most intimate sense of participating in the numinous is an illusion.

Instead, the trend of current neuroscience seems to argue that the enormously powerful sense each of us has of a self as distinct from the matter of which we are made is false. Our minds, our selves may be real—but they are the outcome of a purely material process taking place in the liter or so of grey stuff between our ears.

(There are dissenters to be sure, those that argue against the imperial materialism they see in contemporary neuroscience. See this essay for a forceful expression of that view.)

I do know that this line of thought leads down a very convoluted rabbit hole, and that’s not where I am trying to go just now.

Instead, the reports of the Iraq suicides demonstrated for me that the way the news of the materiality of mind is is slipping into our public culture without actually daring (or needing) to speaking its name.

That the problem of consciousness is still truly unsolved matters less in this arena than the fact of fMRI experiments that demonstrate the alterations in brain structure and metabolism associated with the stresses of war or the easing of the blank, black hole of depression. The very piecemeal state of the field helps mask its potentially inflammatory cultural implications.

To me this suggests two possibilities. One is that it is conceivable that when the penny finally drops, we might see backlash against technological interventions into the self like that which has impeded stem cell research in the U.S.

On the other hand, I don’t think that the public can be motivated or even bamboozled into blocking the basic science in this field. Too much rests on the work; any family that has experienced Alzheimers knows just how urgent the field may be — not to mention anyone with a loved one in harms way.

This actually gives me hope for a shift in the culture war. For all the time and energy wasted over the last several years defending the idea of science against attacks on evolution, with the cosmologists taking their lumps too – the science of mind could force a shift in the terms of engagement decisively in the right direction.

Or I could be guilty of another bout of wishful thinking. Thoughts?

Image: Brain in a Vat, article illustration. Offered in homage to my friend and source of wisdom, Hilary Putnam, who introduced the brain-in-a-vat thought experiment in this book. Source: Wikimedia Commons.

  • Don

    “All this seems to me to be a good thing…”

    Is the good thing that we are adopting the materialist model (because this is the realistic and modern thing to do), or the increased understanding (we’re better able to solve the psychological problem like depression and schizophrenia)?

    It’s the later that concerns me. I just wonder if we have the wisdom to fix problems and not do more – from curing deviancy (homosexuality, left-handedness) to plugging the masses into the Matrix. Both could come from of such a comprehensive understanding of how our brain works.

  • jeffw

    It’s the biggest question of all. Realism vs Idealism. Certainly Realism has been more useful so far. Personally, I don’t think science can completely solve the consciousness problem, tho. Science seems to require at least a grain of objectivity, but when it comes right down to it, is there anything that isn’t subjective? What is there without the self? If the self cannot think of it, it cannot be known, understood, or said to exist. Of course, none of this necessarily implies “God” or religion. But it does question the omnipotence of science and materialism.

    And science does seem to have limits. If you keep on reducing things, eventually you come to something atomic that has no explanation, and all you can say is “that’s just how it is. Tough.”

  • Mike

    I think you’re too optimistic. I think non-scientists generally don’t appreciate the power or ubiquitousness of science. For them, science is allowed to work in its own corner of the world, but it doesn’t have to apply everywhere. For example, a few days ago I talked with someone who described two doctor friends who wholeheartedly believe in ghosts. Presumably, these people know a little about electromagnetism and Newton’s second law, but they still think some invisible being can walk through walls and open cupboards. I’m sure there are plenty of anti-evolutionists who feel the need to renew their flu vaccination every year.

  • Brando

    Part of the problem is that whenever you spend a significant time in a combat zone, especially with a high operations tempo, your perception of “normalcy” slowly starts to change. After a year or so everything starts feeling surreal as if the completely abnormal is now the standard. This is where all kinds of irrational and superstitious behavior seems to happen and combined with the dire frustration some of us felt over there, it’s not surprising that depression can take hold. Combine that with a rotation back home and all of a sudden you have a completely reset view of “normal.” Life in a combat zone is very incongruous.

  • Ijon Tichy

    By the “culture war”, are you talking about the creation-evolution “debate”, and the related God vs Big Bang “argument”? Because if so, in the Western world, this is a uniquely American issue. To understand this culture war, you need to ask why America, and nowhere else in Europe? I think it’s largely a psychological question.

  • Jonathan

    I’m afraid you’re underestimating the ability of many Americans to ignore connections they don’t want to see. “Evolution? Bad! Cosmology? Bad! Pills to make me feel better? Sure, why not? — they didn’t come from science, they just happened.”

  • Slide2112

    What is your “hope for a shift in the culture war mean” Is it a stronger understanding of science or a shift to materialism or a is it a move away from religion? All different things.

    You mention the steam cell debate, a materialist might suggest a fetus is nothing but a biological process Do we really want to go down that road? It is not hard to accept that life itself may be a byproduct of chemical process, but an abortion after 3 months makes me squeamish, after 5 months, forget it, that’s a baby.

  • Plato

    Frank Wilczek:Force is an abstraction of this sensory experience of exertion.

    Taken from the “Reference Frame” on page 4 last paragraph.

    There is always this attempt for a Synesthesia interpretation that combines such momentums with the psychological aspect of something we can identify in nature? Empathetic, to what nature is actually doing? Did Sir Isaac Newton have “this claim” to fame? Optics? Feynman’s toy models in a “conceptual form?”

    Now, how is stress measured in this psychological perspective, and how is it retained to manifest in a physiological response. I talked to a fellow who was in the Korean war at the age of 20, who experienced fear, and he felt this fear in his belly consistently for years. He said many of his mates did too, even after leaving, and surviving. Letting go of the fear, meant then to let go of the trembling hold it had in the belly?

    Now while sitting in his vehicle, he relates to me the cause of his cancer, as he extols this history. Is there a correlation? Or, is it genetics?

    So such dramatic experiences do take their toll, and if the mind is not capable of assuming the reality of the situation, then it becomes the object of it’s focus? These “formative subjective realizations” become real?

  • sn

    We are so far away from a one-to-one understanding of the brain, that this discussion is way out there for me. In evolution, we have already scored and in cosmology we know exactly when we score.

    In brain science, the way it is right now, we don’t even know WHAT it means to score.

  • Peter Morgan

    I think the relationship between brain states and mental states remains statistical and anecdotal; indeed insofar as there is a category difference between material and spiritual I’m not sure whether neuroscience can deliver a causal account for the relation between them. Proving the relation to the satisfaction of a religious certainly and rightly requires a lot more evidence than the already convinced materialist needs to leap to the conclusion that there is no spiritual in the world.
    There is a further problem for the reductionist that is an easy recourse for the religious, which is that we have very little handle as yet on the nature of the emergence of different categories of phenomena in general from the reductionist theories that are supposed to explain everything. The interplay between emergence, complexity and reductionism is far too little explored as yet to justify strong statements either way — at least not with any pretense to academic rigor. Of course the question of complexity is something of a graveyard for academic careers, it’s far too hard unless a very narrowly defined approach is taken, so only very slow progress is made. From a layman’s point of view (a physicist very little read in neuroscience research), the technology of neuroscience appears to miss the question of causal emergence of mind from cellular biochemistry. The content of the research literature seems to be restricted to the noting of progressively more detailed classes of empirical correlations between electrochemical and measurable mental states (with which good luck, because it’s useful, but it falls to the usual problems of the philosophy of science, perhaps most seriously the problem of induction).
    This is to pick on the most theoretical aspect of your post, a bugbear of mine, for which I apologize. I found the post as a whole moving and thank you for it.

  • Herb

    For those who are interested, Disabled American Vets is a charity that recognizes the need for veterans’ psychological treatment, including for PTSD.

  • Greg

    What ‘culture war’?
    According to the premise of this article, it is all just electro-chemical activities in the brain: there is no more a culture war than there is a self.

  • Mike B

    I think your interpretation of the fMRI experiments and similar evidence show your bias toward finding the source of consciousness in the material. Maybe the “other side” in the culture war just interprets these facts (if they pay them any attention at all) in the opposite way.

    I suggest that finding measurable alterations in the physical substance — correlated with subjective changes in the emotional state — may not be a clear-cut case of cause and effect. Isn’t it entirely plausible that the same people who see bacterial flagella as God’s signature may see this as a demonstration of the unique importance of the mind, and its (sacred?) dominion over matter?

  • Plato

    AS a layman, I wonder too.

    Peter Morgan:The interplay between emergence, complexity and reductionism is far too little explored as yet to justify strong statements either way — at least not with any pretense to academic rigor. Of course the question of complexity is something of a graveyard for academic careers, it’s far too hard unless a very narrowly defined approach is taken, so only very slow progress is made.

    Maybe without sounding to mysterious, the sphere of influence( our own inverse square law[ Gr taken to new heights of definition?]) that we have in our relations, holds a “much more then” an materialistic interpretation in a “physiological discourse” that has emotive valuations which may actually be understood?

    That such a building blocks of emotively backed “units of consciousness” might be considered in the same vain?:)

    Such “elevations( a boundary condition?)” may give perspective about our relations, and the effect of the war on our consciousness, as we colour it red(anger, fear)?

    These then become more then the values of the distance in between the mass 1 and 2( what measure is this in the world without mass?.[ I am not sure how to define this without context of energy/energy and mass/mass being introduced together, can be mass/energy in one’s interpretation?]) Sorry for the confusion. An “oil sheened bubble” would not be to far off an analogy in my confusion:)

    QQ measures hold different valuations then when we put this “new spin” on the “depth perception and what it entails in our relations?”

  • Big Vlad

    plato, you don’t half talk nonsense

  • Tom Levenson

    Thanks again to all who have commented.

    Just a couple of thoughts:
    Don (1): good thing = increased understanding. I accept, certainly, the dystopic potential of brain science. But I’ve lost people dear to me to Alzheimers, and I do think that a better grasp of the physiology of self is of enormous value.

    Sn and Peter Morgan (9, 10): I fully agree that the connection between brain and consciousness is still far, far away from a one-one correspondence. I believe, in fact, that this is a problem that falls into what the philosopher Hilary Putnam warned of in a paper from long, long ago when he talked about the kinds of category mistakes that come from misplaced levels of abstraction/explanation (e.g. don’t try to explain cell surface receptors by solving the QM equations to describe the behavior of individual electrons within a protein.) That is: the problem of consciousness, the equation of mental states in detail with a circuit-by-circuit map of brain states may be unsolvable.

    But I do think that the circumstantial evidence that mental states are the expression of brain states is significant and growing stronger — for the reasons cited in the post and more that do not fit into even my expansive notion of how long such posts should run. If I were to make a very rough analogy — I think that modern neuroscience is roughly where evolutionary biology was in the early 19teens: knowing Mendelian genetics and that fruit flies were interesting, and not all that much more. (Perhaps the same historical comparison applies to cosmology. Consider the state of speculation before GR and before the scale of the Milky Way was properly understood). That we are as ignorant of the brain-mind connection in detail now as we were of the mechanisms of evolution then seems to me true, but not necessarily discouraging.

    As for the various comments pointing out my optimism re the ability of the public to hold contradictory views. Sure. I concede. But at the same time I retain reasonable hope, for several reasons. Mostly, I think it is worth remembering that while it’s easy to doom and gloom, but in fact the science world view is, I think, in better shape than it often feels i the trenches. Part of the reason you see places like the Discovery Institute crop up is because its partisans realize that they have to fight (dishonestly) on our turf: the arguments they make are couched in the rhetoric of science because they rightly see that science is to the public as well as the profession, a remarkably successful way of looking at the world.

  • Neil B.

    Interesting, but of course we knew that what we experience and what happens inside our heads “correspond” in some sense. The better insight is to appreciate that the *nature* of what happens there is particularly susceptible to relativity of observation and context (some have compared it, loosely or not so loosely, to the way wavicles can manifest as particles under some conditions and waves under others.) In other words, the “character” of conscious experience like other things is conditioned by it being what happens in your own head, and not something you contact some other way. Indeed, things aren’t just “given” to us, they are as revealed in a context of observation. The “observation” is perhaps more real and given than the mysterious thing in itself behind the observation. The observation, the interface, can take different forms despite being based on the same thing. That is the source of much of our perplexity, since we cling to the illusion of the common objective space, the existential absolutism that properties are intrinsic givens. That’s why color experiences have a qualitative feel for us, but that isn’t something you find as such in the brain.

    Also, if our minds are more about what happens inside our brains than the brain itself, then they are more like a computer program than like a computer. Note that a computer program can run on a different machine than that it first ran on, so our minds aren’t really limited to being trapped inside a particular skull. Maybe they can “run again” on some platonic supercomputer (you’ll need to look up “modal realism” and read some Frank Tipler or Rudy Rucker to better appreciate my point.) Life after death, and made credible by the most abstract functional thinking rather than religion! What an irony, for any materialist to ponder.

    Actually, the ultimate irony for a “materialist” is that the idea of “material” apart from a conceptual structure (or call it model world, platonic reality, etc.) is logically incoherent. Really, I kid you not – you can’t pin down whatever makes a so-called material world and its “stuff” exist in a way different from some sort of description or mathematical configuration of the same world, assuming it can be so modeled at all (big if.) That’s the argument of modal realism, please look up in Wikipedia. But once you accept that, then there’s no reason for some model worlds to exist and others not to, they all exist equally. Max Tegmark says he believes it – but more irony, since such a notion is not verifiable. (How can you build a probe to enter other “logically possible worlds”? There was a cool SF novel about that called “The Infinite Worlds of Maybe”, and of course the “Sliders” TV series. Neither got much into really different worlds of alternate laws etc.) It is a most perplexing conjunction of the strictest logical discipline and the wildest of metaphysics.

  • Paul Murray

    I do not agree that the main challenge of physical monism is that it calls in to question our experience of the numinous. I think its main challenge is that it tells us that we have no reason to suppose that an intelligence can exist without a physical brain to host it.

  • jeffw

    One of the simplest arguments against the (fully) material basis of mind was put forward by Thomas Nagel in the 1960’s. I think it’s called something like “the Indexical argument against Materialism”. It says that in our physical system, you have everything you need to construct any number of conscious brains that make up our reality – except for one item of information that’s missing: which one of those brains is “you”? Where is that index information encoded in the physical system? It’s missing. And it’s not a trivial piece of information, either. Reality would be much different if you were a dog, an advanced computer, an alien in another galaxy, or a being in another universe. The same problem is also expressed in the childhood “why am i me” question, or: “why is reality being experienced from my perspective, and not from the perspective of someone or something else.” If everything is material, then what is the material explanation for that fact? Of course, there is none…

  • Matt

    I can’t say I’m convinced either. Sure mental states and thought processes are generated by the brain, but this is a far cry from saying our selves are generated by the brain. There’s as many stars in the galaxy as there are neurons in the brain, all interacting. No one serious would argue that the galaxy is conscious, so what about the structure of the brain’s interactions is privileged to generate something qualitatively different like a conscious sense of self while other equally complicated processes are not? Worse, what experiment could tell the difference in what systems are conscious and what aren’t without begging the question?

    I don’t think neuroscience or physics is equipped to handle this. It’s essentially the Problem of Other Minds, which is intrinsically not something that’s amenable to data collection and thus not science in any meaningful sense.

  • rww

    for those who believe in a non-material component, does it extends to all sentient creatures, in degree?

  • Daniel Black

    Matt said:

    There’s as many stars in the galaxy as there are neurons in the brain, all interacting. No one serious would argue that the galaxy is conscious, so what about the structure of the brain’s interactions is privileged to generate something qualitatively different like a conscious sense of self while other equally complicated processes are not?

    Once, no one serious would have posited many things which we currently take as valid theories (“theory” in the stronger scientific, and not weaker colloquial, sense). Your suggestion that “[n]o one serious…” is an ad hominem attack on anyone who might make such an argument. The fact is, if the brain’s structure and processes are the mind, then there is valid (if terribly difficult to investigate) conjecture as to what else might also have gained consciousness. There is nothing about such an argument that is a priori fallacious. It does certainly challenge the idea and quaint intimacy we attach to our consciousness, but that’s no reason to dismiss it.

    jeffw said:

    It says that in our physical system, you have everything you need to construct any number of conscious brains that make up our reality – except for one item of information that’s missing: which one of those brains is “you”? Where is that index information encoded in the physical system?

    If I understand your question correctly, I’ll respond by telling you why I think cassette tapes are more elegant a solution to music storage than digital media: the universe keeps track. I can play my mixtape today, stop halfway through the third song, put it in a drawer for a year-and-a-half, pop it back in a player, and continue where I left off. There are some statistically mechanical things going on, sure, so the medium will degrade a little; but by no additional effort on my part, and with no powered, chip storage of any device, I can start very close to where I left off. This is because the physical processes are conservative, and, again, the universe keeps track.

    Why wouldn’t the source of “you” arise similarly? Is there nothing about which brain is operating in whatever fashion giving rise to certain cognition itself the index?

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  • Matt

    Daniel Black: The fact is, if the brain’s structure and processes are the mind, then there is valid (if terribly difficult to investigate) conjecture as to what else might also have gained consciousness. There is nothing about such an argument that is a priori fallacious.

    That’s my point. There’s no way telling experimentally if (for instance) a galaxy is conscious – or for that matter no current way of telling anything experimentally about the “what’s it like, if anything” aspects of mind for humans, machines, or otherwise. It is entirely possible that such an experiment is impossible even in principle, though I wouldn’t be prepared to bet on it. But if there’s no way to test experimentally, it ain’t science.

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  • jeffw

    Why wouldn’t the source of “you” arise similarly? Is there nothing about which brain is operating in whatever fashion giving rise to certain cognition itself the index?

    If you can identify what that source is, be my guest. Note that there can only be one source – not only in this universe, but in the entire multiverse (assuming a multiverse exists).

    The whole question of conscious identity is quite elusive. When you say that consciousness emerges from a physical brain, you have to be careful that you don’t conflate “conscious identity” with “physical identity”. Theoretically, you could replace all the neurons in your brain, one by one, with equivalent synthetic components, and you’d still be the same conscious “you”. Physically, you’d be quite different, buy consciously you’d be the same person. And neurons are dying all the time, but you’re conscious identity does not change or shift from one person to another (although, I suppose there would be know way of knowing that, due to memory).

  • rww

    No. 24 says “there’s no way telling experimentally if a galaxy is conscious.”

    In the absence of gods to plant the seed, if consciousness resides anywhere in the universe, then the universe can fairly be said to have evolved to a state of consciousness. All else is vanity.

  • James Nightshade

    Perhaps Professor Levenson could use his insights into the Material Basis of Consciousness to reduce the suicide rate at MIT.

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  • Rev Jim

    While materialism is a step up from superstition and magical thinking, it is not necessarily the final step. Nothing that I’ve seen in scientific materialism addresses the issue of what causes evolution (of the universe, for that matter) – somehow randomness does not seem like a final answer.

    The physiological changes in the brain associated with PTSD and other diseases and disorders have been shown to be developed through the thoughts of the individuals (and sometimes of groups) involved. If thought is an epiphenomenon of the brain, how then can that thought change the brain?

    I am excited to see what scientific developments arise in the future – the expansion of knowledge is always welcome, and usually not predictable. How often have we heard the “final” answer, or that there is nothing else to learn, only to have an astounding, revolutionary discovery follow in short stead.

    I think that it behooves materialists to be open to something greater emerging as we develop the capacities to explore the greater universe and the inner human being.

    Perhaps as a result of scientific exploration we will trade the old God of myth for a more mature understanding of the mystical nature of matter. Not a created and directed universe, but an “informed universe.” (see Ervin Lazlo).

    Rev. Jim

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  • Gene Johnson

    If anyone thinks they can come up with a Theory of Everything without directly involving consciousness in the equation, they need to catch up on some Kurt Godel. Science and religion are two sides of the same coin which is about to collapse into a new coin.

  • Dima

    Neil, do you know where I can find that novel you mentioned? I googled it but came up with nothing


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About Sean Carroll

Sean Carroll is a Senior Research Associate in the Department of Physics at the California Institute of Technology. His research interests include theoretical aspects of cosmology, field theory, and gravitation. His most recent book is The Particle at the End of the Universe, about the Large Hadron Collider and the search for the Higgs boson. Here are some of his favorite blog posts, home page, and email: carroll [at] .


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