Here are my thoughts on what modern neuroscience can tell us about consciousness (part 1). In short, the process of consciousness activates very specific brain regions, and neuroscience as actually done a splendid job at showing why experiential and action potential are the same thing.
Humans are thinking things that think things. Consciousness, perhaps, is the most personal, the grandest, and the crème-de-la-crème of these things. It is our magnificent ability to introspect, our mind’s “I.” And yet, our brain does this almost effortlessly by stringing together our past experiences overtime to construct a seemingly coherent story of the world within. It’s like taking thousands of points of experiences, and connecting them with a “best-fit” line to preserve the story of our self from moment to moment, day to day, year to year.
As a quick caveat, I use “consciousness” here as an umbrella term encompassing the varieties of conscious experience, each surely recruiting different but overlapping neural networks (e.g. visual awareness, conscious recollection, self-awareness, and so on).
In terms of the basic elements from which our bodies are assembled, we are no different than the stars above us or the earth beneath us or the splendid variety of organisms around us. So, then, how is it that our subjective feelings, what philosophers have termed qualia — our experience of the blueness of the sky or the pain of a toothache — arise from objective and physical stuff? How does the brain achieve the mind’s “I” when it is made up of mindless, I-less, brain cells? Well, when 100 billion brain cells get together and connect in trillions of ways, seemingly magical stuff happens. Emily Dickenson wasn’t too far off when she wrote, “The Brain is just the weight of God.” Note the coincidence of capital letters.
I’ll let the cat out of the bag now: while we don’t know the exact neural mechanisms that produce consciousness, we do know that the brain is necessary and sufficient for consciousness. That much is irrefutable. We also know a great deal about the neural systems involved in various aspects of conscious thought. Neuroscientists are working at breakneck speeds to solve these problems, as it is arguably the Holy Grail of neuroscience. The purpose of this post, then, is to convince those who need convincing that consciousness can be explained by brain activity alone.
We don’t need to invoke some transcendent or spiritual elixir that animates the inanimate. We don’t need to invoke God(s). We don’t need to invoke a “soul.” 100 billion brain cells organized in the right patterns and firing at the right time is all we need, because that’s all there is. “The whole purpose of science is to keep us from mistaking what we’d like to be true for what really is true,” evolutionary biologist Jerry Coyne reminds us.
Not Even Wrong: The “Easy” and “Hard” Problem, and the Emperor’s New Mumbo Jumbo
The philosopher David Chalmers proclaimed famously that consciousness could be divided into an “Easy” and “Hard” problem. Describing all the physical neural pathways necessary to produce consciousness solves the Easy problem. Explaining how physical stuff can give rise to our subjective inner life solves the Hard problem. Many, including myself, disagree: there is no “Hard” problem of consciousness, because once we explain all the neural pathways involved in the process of consciousness, then we will have explained how subjective experience itself is produced as well.
No scientist is taken seriously if he or she argues that the DNA-Nurture combo cannot largely explain the heritable traits or the development and functioning of an organism. Just because the information isn’t obvious in sequences of nucleotides doesn’t mean it isn’t there. Mother nature doesn’t care about our hypotheses.
And we shouldn’t for a moment take anyone seriously who argues that consciousness cannot be explained by measuring neural activity alone. It is a measure sufficient to show that the “Easy” and “Hard” problems are one and the same. To those who disagree, the question I pose back is, What else is there left to explain?
Just because we label our awareness as “subjective” does not entitle it some immunity to scientific scrutiny and explanation using empirical measures. Put simply, we solve the “Hard” problem by solving the “Easy” problem (which itself isn’t so easy since it involves relating molecules to cells to circuits to systems to mind and behavior). So much for Chalmers.
Moving forward in our tour of demonstrably-false-and-based-on-zero-evidence claims, in “The Emperor’s New Mind,” Physicist Roger Penrose argues that the laws of physics just aren’t cut out to explain consciousness. (The anesthesiologist Stuart Hameroff sadly argues this same point as well). So where does he look to find an answer? He invokes the esoteric, wholly unrelated notion of “Quantum gravity” at the level of microtubules, which are structural components of cells.
And so he deserves only one rebuttal in this post:
No one is going to contribute anything of serious consideration with regards to consciousness through “quantum gravity effects” in microtubules, in the same way Watson, Crick, and Wilkins would not have discovered the double helical structure of DNA if they studied it at the level of electrons (as neuroscientist V.S. Ramachandran reminds us in the video above). It’s the wrong level of analysis, has gained zero experimental support, is hardly falsifiable, and makes no real testable predictions. It’s just a wishy-washy windbag of an argument.
Please, anyone who has taken a cell bio class go here and share my sentiments. Francis Crick criticizes Penrose mildly by saying, “At bottom his argument is that quantum gravity is mysterious and consciousness is mysterious and wouldn’t it be wonderful if one explained the other.” Yes it would be wonderful, but it just isn’t happening.
(For a completely eviscerating critique, see Ch. 15., The Emperor’s New Mind and Other Fables,in Dan Dennett’s “Darwin’s Dangerous Idea”). Despite his training as a physicist, Penrose seems too emotionally invested in his solution to give it up, and in the process forgets that data and evidence are emotionally independent measures. And so, his is a nice attempt at relating a process that no one understands to a process that has nothing to do with it.
The “Mind-Body” Problem, or better put, the Mind-Body “Problem”
Penrose isn’t alone, however. Dozens of other scholars for one reason or another don’t believe that science in general or neuroscientists in particular have what it takes to solve the mind-body “problem.”
Let’s look at the most common arguments. Matthew Segall, known popularly as “0ThouArtThat0” on youtube, is as eloquent as any up and coming philosopher – an eloquence rivaled in magnitude only by his deep misunderstanding of how science works. His musings on consciousness and God are admirable and bold, and it is refreshing to see a philosopher who doesn’t shy away from scientific theory. But he is also an example par excellence of a thinker who just gets science wrong.
I’ll rehash some of his claims because they echo the thoughts of numerous philosophers and – I hate to say it – even some scientists (these scientists tend to be more like Penrose and less like, say, Koch or Crick).
“Without a human brain, human consciousness is not possible… But it does not follow that consciousness is located inside the skull…”
“All the empirical studies of the brain that have ever been done and that could ever be done reveal only a correlation between experience and neural tissue. No causal relationship can be shown empirically…”
“No matter how hard we try to look for our own subjectivity in the brain, we will find only objects other than ourselves. You can’t see consciousness. You can’t feel it… This is why it is a category mistake to think empirical science could account for it in terms of brain activity alone.”
Really? You do not know, then, how precise our tools are. And so, allow me to lend a machete to this intellectual thicket. For starters, read this. It’s a nice and thorough review of what scientists mean by “consciousness” and the various, often clever, methods being used to show the connection between neural tissue and thought. (I purposely left out the word “correlate,” because as the studies below will demonstrate, causality is a realistic claim using today’s techniques).
Discovery stops when we sit down on the armchair and bask in awe at the magnificently complicated process of consciousness, and this awe blinds us to the tractability of the problem at hand. (To be fair, scientists often are up in the Ivory Tower for too long and forget to come down and share the importance of whatever experiment is brewing.)
The Neural Code
The scientifically astute philosopher Dan Dennett summarizes my criticism beautifully: “I cringe when I see young philosophers doing a smarty-pants demolition number in front of scientists, a talk that would go down like honey in a room full of philosophers but merely makes the scientists shake their heads in dismay.” We’re all shaking our heads.
Dennett’s critique makes a fundamental distinction between philosophy of science and philosophy in science. The latter is a scientist’s compass when navigating through the edge of what is known and unknown — that much is unequivocal. (For a full review, click here eagerly and scroll down to “2009,” 6th article down).
If we can explain how, when, and why neurons fire in particular patterns, interact with various other brain regions, and finally produce a particular behavior, then we have described all there is to describe. Calling this a “correlation” is a deep misunderstanding of the term, and it’s what happens when a rookie throws his hardest 35mph intellectual fastball at the hard-hitting Babe Ruths of science.
Neuroscience has already begun to objectify subjectivity, because “subjectivity” is simply a misnomer, and a very appealing one at that. It implies that our ability to think inwardly and reflect on the world and ourselves is unknowable to anyone but ourselves. We can’t possibly peer into your brain and see your consciousness or your thoughts about yourself unfold, can we?
Here, Obama would be proud to say, Yes we can.
To argue against this notion is to kick nearly a century’s worth of electrophysiology research and a few decade’s worth of human imaging data to the curb, to say nothing of the molecular biology and neuropsychology camps. Today, we can take electrodes, implant them in brains, have them readout the firing patterns of brain cells, and re-construct with great confidence what the brain cell’s were representing.
In essence, we’ve decoded a thought. This one aspect of neuroscience has been applied across the evolutionary ladder, from fruit flies to mice, monkeys to humans. Here’s an extended review, for your viewing pleasure or dismay.
And because something as complex as consciousness occurs by the same rules that I just described — brain cells firing in a particular order at a particular time — it, too, is subject to decoding.
Traveling at the speed of Thought
Ah! Let us tour the human brain briefly to convince the Penrose’s and Chalmer’s — hereafter referred to collectively as the Palmers — and Segall’s out there that neuroscientist’s are actually doing a fantastic job at figuring out the nitty gritty of consciousness, that it resides solely in the brain, and that it can be explained solely through brain activity.
Here are just a handful of studies out of the hundreds, if not thousands, that have been done. It should be no surprise that the evidence overwhelmingly dissects consciousness at a finer and finer resolution, and there’s no reason why this trend won’t continue.
Like any other activity, the process of consciousness recruits much, though surely not all, of the brain. These regions include, but are not limited to, the parietal lobe and its role in focusing attention, the frontal lobe and its ability to integrate various aspects of perception, and the anterior insular cortex, with its ability to at least partly mediate attention.
And just to give a shout-out to the hippocampal memory system (my personal favorite, since it consumes my life in lab), here’s a thorough review of the role this memory system may play in consciousness.
But wait! There’s more! Electrophysiological studies galore! Here’s some striking evidence that gamma oscillations are involved in integrating the activity of numerous neural networks, specifically during awareness or attentional shifts.
After all, we experience the world and ourselves through all our senses and as a smoothly occurring story, not as a blooming, buzzing confusion, as psychologist William James would have called it. If this still not enough cutting-edge biology for you? Try this, with a reader-friendly summary here.
Is this now not enough psychology for you? Recent studies on split-brain patients also provide wonderfully vivid windows into the power of our brain to construct all sorts of narratives — including a narrative of the self. Neuroscientists Michael Gazzaniga and Rogery Sperry pioneered a series of studies dissociating some of the roles that the left or right hemisphere of the brain played in mediating consciousness.
Split-brain patients often have had a major nerve bundle connecting both sides of the brain severed. Accordingly, Gazzaniga and Sperry presented certain information to the right-hemisphere, but not the left-hemisphere, and vice versa. When information was presented to the right-hemisphere, it couldn’t be communicated to the left-hemisphere in light of the damaged bundle.
In this case, the left-hemisphere (which is largely responsible for our ability to speak) often interpreted, or confabulated, a story to make sense out of the disjointed presentations, rather than treating each presentation individually. Gazzaniga and Sperry propose that these disjointed presentations are no different than our day-to-day disjointed experiences, which get somewhat smoothed over to keep our self-narrative coherent, to make order out of our daily chaos. Here, our brain’s contributions to consciousness were both measurable and evident.
Or if you want to get really philosophical, then chew on this: we’re made from the same star-stuff as the rest of the universe; therefore, we ourselves are made in the image of reality. Surely natural selection would have picked off those who weren’t accurately representing reality to a large extent, since falling off a cliff is only a good way to transmit your genes to the ground below.
Sex is a better way, and given that environmental pressures are always present, a nervous system that could accurately represent the world around us (such as a mate, or a meal, or a predator) is the kind of stuff over which natural selection has a field day.
A single brain is the universe folded in on itself, shaped by billions of years of natural selection and evolution, molded and re-molded by its own ability to think and figure itself out. It sounds to me like neuroscience should have landed the final blow to solipsism by now.
The Same ol’ Tune
I’ve saved some parts of the Penrose/Segall arguments for the end, so that by now you should be able to anticipate them and see the faulty logic.
“No amount of empirical study of the brain will explain conscious activity or thinking, since these are the pre-conditions of any empirical study. Neurochemical processes are involved, I have no doubt, but it is a gross category error to assume there exists some description in terms of external material events alone that might account for mental experience.”
On what basis is there a dissociation between the material and mental experience? The claim is wholly unfounded and, as usually is the case, is lacking any sort of evidence at all. Here’s a quick syllogism: Mental experience is the product of neural activity. Neural activity is anchored only to the realm of physical laws. Therefore, mental experience can be explained fully through physical laws. QED.
If you were to take out your brain right now, it would resemble more of a pudding and less of a hardened jello. If you were to stick your thumb through this pudding, your entire experience would change depending on the neural systems interrupted. You might go blind. Your personality might change. You might lose some memories. You might lose your ability to pay attention to half of space.
Is all this too correlational? Well how about achieving cell-type specificity in, say, the monkey brain and manipulating its activity on a millisecond scale, which in turn still manipulates a very specific behavior. I don’t know what can possibly be more causal than that.
If history can teach us anything, it’s that starting a sentence with “No amount of empirical study will explain….” is doomed from the get-go. Just look at those who said that God was responsible for pushing the wheel of creation forward and then letting it roll on its own (i.e. intelligent design).
And then look at Stephen Hawking’s reply that God is just not needed to explain the grandest of questions – why is there a universe at all? Physics is this close to closing the door on that question. Inevitably, not everyone agrees, especially them.
Even John Horgan at Scientific American laments that if (when) we crack the neural code, “[It]will be so hideously complex that it won’t give us the sort of intellectual and aesthetic satisfaction—the “Aha!”—we crave.” His pessimism is also unfounded here.
Once again, to John, what is your basis on which to humble science’s rigor with your completely-opposite-of-a-hypothesis-driven conjecture? Where is your evidence that a “hideously complex” process can’t be explained in layman’s terms? No one doubts that DNA replication is a complex process, but molecular biologists have studied it so feverishly that different levels of valid explanation exist.
Take this one: When a cell reproduces itself, certain enzymes assist in unwinding a double-helical strand of DNA, and each strand recruits the necessary machinery to replicate itself using complimentary bases. See — was that so hard? And I didn’t even break a sweat with details, and neither did the reader. Just because it’s the thing in our head we hold nearest and dearest doesn’t mean consciousness is an exception.
Where else would we look?
Another argument (“argument”): “It’s a mistake to try to locate [consciousness] inside the skull. It is emergent, not just out of neurons, but out of space-time as a whole”
Hyperbole: I’m not going to take a delicious, medium-well, kobe beef burger and bring it into the lab to search for how it contributes to my consciousness just because it, too, is connected to my brain in that it is also made “out of space-time as a whole.” To say something is “emergent… out of space-time as a whole” is to get absolutely nowhere.
Let’s call it the world’s most redundant, superflous, and obvious statement. Everything is “emergent” out of space-time, so please, the next step is to zoom in the microscopes and narrow down the field of inquiry from the entire universe and space-time itself to subregions X, Y, and Z in the brain — the place where all the action in question indeed takes place.
As a caveat, I would never argue that everyone has to be a bona fide neuroscientist to understand or appreciate how the brain works — knowledge is everyone’s privilege. I’m simply arguing that one should know what he or she is talking about by understanding the process at hand and how it is being studied rigorously by others in the field before making grand and empty claims on the impossibility of explaining it.
The Mind-Pearl is a product of the Brain-Oyster
Admittedly, I’ve taken a strictly reductionist approach to consciousness, but scientists are working both from the bottom up (e.g. molecular neurobiology) and top-down (e.g. social psychology). Do we lose the forest of consciousness by studying the trees of neurons? Absolutely not.
Explaining something objectively does not mean we’ve explained it away. We’ve just made the mind go from orderly to intelligible. The physical brain is linked to the conscious mind in that the former produces the latter, and all we need is an N = 1 event to falsify that claim. As of now, that N = 0.
Also, calling consciousness an “emergent” property is, I think, the ultimate cop out. Some philosophers juke and dodge in the same manner, calling it an “epiphenomenon.” Saying it is “emergent” is the same as saying we have no idea how the sum of the parts comes together to give rise to the seemingly greater whole. But how have so many become convinced that this is the case in neuroscience?
The mind-pearl is a product of the brain-oyster, as Dennett puts it. But the analogy stops here, because the mind-pearl — consciousness — isn’t located centrally in one specific brain region, and this concept is so unintuitive, so unnatural feeling, that people react with disgust and simply reject it. There is no screen on which our consciousness is projected in our brain (a “Cartesian Theater”). Our brain is the producer, theater, and audience at once.
And here’s one last Palmer/Segall claim: “If I desire knowledge of consciousness, knowing the details of serotonin re-uptake and sodium potassium pumps, etc. is certainly helpful, but it does not exhaust the scope of the phenomenon (and noumenon) in question. There are other modes of inquiry besides empirical science that are relevant to the study of consciousness.”
Of course there are other modes of inquiry! The arts and sciences presumably act as mirrors on which to reflect on our nature. The Russian playwright Anton Chekhov once said, “Man will become better when you show him what he is like.” We need the philosophers, the biologists, the economists, the artists, and so on, to tell us about where we come from, who we are, and where we are going. No one is denying that — but our experienced reality can be quantitatively measured and physically manipulated, and the beauty of this claim is that you don’t have to take my word for it – just look at the data and they’ll be orders of magnitude more convincing.
Knowing the details of serotonin re-uptake, sodium-potassium pumps, which brain regions are active during a particular task… name_your_neural_event_here is helpful, necessary, and sufficient. Needless to say, neuroscience will continue to chip away at the mind-body problem until it can finally and fully explain how a 3-pound lump of meatloaf gives rise to the entire spectrum of human achievement — from the stone tools of Homo habilis to that frustratingly tantalizing thing we call consciousness.
Ralph Waldo Emerson once famously quipped, “If you’re going to shoot the king, you had better kill him.” Opponents of neuroscience’s march forward miss their target by a wide margin. The result has motivated our march to become an evidence-driven sprint towards the Holy Grail of neuroscience. The arguments to the contrary aren’t even wrong – they’re just flat out untestable empty fluff.