Here are my thoughts on what modern neuroscience can tell us about consciousness (part 2). In a nutshell, despite their complexity, neural systems are perfectly suitable to represent our “selves” over time. This seemingly magical process can be explained by brain activity and brain activity alone.
Matt and Ronan,
While I have my reservations with your views on consciousness, it is refreshing to see two thinkers who engage fully in a dialogue – I would argue the dialogue – between science and philosophy. Many from both camps in the past have attempted to burn that bridge, and I applaud both your efforts at critically dissecting both fields rather than polarizing them. When the “problem” of consciousness is no longer a problem, it will be because it was attacked on a multi-disciplinary scale, not unlike our own on-going conversation.
Also, in this reply, I’ve made every effort to present the reader with the “mountains of evidence” I so frequently mention, because they are truths worth propagating.
What Neuroscience has Discovered Thusfar
For the sake of completeness, I’ll restate my argument: there is no difference between a physical or mental event, because neurons are very well equipped to perform a spectacular variety of mental functions, including consciousness. I make this claim in light of a neuron’s specialized ability to integrate all sorts of inputs from the external world while also responding to inputs from within the body. This confers the ability to represent information by changing both its own structure as well as the timing and frequency of its own firing, or action potentials (for a review paper on a neuron’s properties click here and for a more comprehensive summary go here.)
When you couple this with all sorts of environmental pressures in our ancestors’ history, then evolution by natural selection gives you the following: you get the ability to remember (e.g. the hippocampal memory system), the ability to paint any memory with emotion (e.g. the amygdala emotional system), the ability to represent sensory information even when it is no longer present to the senses (e.g. the prefrontal cortex and working memory), the ability to bind multi-sensory experiences (e.g. the thalamus and its reciprocal connections with the rest of the brain’s sensory areas), the ability to represent our own body in terms of its position in space, its motor movements, and its sensations (e.g. the parietal lobe and its role in attention, and the motor/somatosensory cortex proper, respectively), to name a few relevant examples.
Neuroscientist Earl Miller has done pioneering work connecting memory and attention, especially with regards to the brain’s ability to hold multiple items in a given thought. Many neural networks often tend to fire in specific frequencies, or oscillations (i.e. “gamma oscillations” or “theta oscillations”), which create optimal windows for communication between neurons. When multiple items are held in attention, they tend to occur during various but different points in these oscillations. These “items,” it has been argued, can include our “self.” (One of Earl’s seminal papers can be found here with a reader-friendly commentary here). This is claimed to be the first real neural correlate of consciousness.
Now imagine all of these brain processes working in parallel.
This is still on the neuropsychological level, but already we can begin to explain our salient, second-by-second awareness of our self over time as a product of specific neural activity — a claim that is not unfeasible, especially when you consider the functional properties of a few more brain regions (e.g. anterior cingulate cortex and anterior insular cortex) specifically thought to be involved in self-awareness (oo! a reader-friendly commentary here!). It is no coincidence that many of the brain regions I just mentioned balloon at around ages 2 onwards, which is about when we begin to have a sense of self-awareness. I would go as far as to argue that a representation of the self both is absolutely inevitable and evolutionarily beneficial with the neural systems that natural selection has given us. Specific qualia are evoked from the interaction of the specific regions I just mentioned, depending of course on the properties of that of which we are aware. So if you’re reflecting on a painting in front of you, it involves the interaction of thalamo-visual-prefrontal networks, which transform and encode the painting (i.e. the stimulus) as a specific pattern of neural firing that you experience. Suffice it to say, there is nothing that distinguishes experiential from action potential.
100 Billion neurons > Comprehension?
The possibility of conscious awareness comes from being able to hold multiple items under attention while simultaneously having memory systems that bestow on us the capacity to remember ourselves over time. The relationship between our remembered self and the “multiple items” in the external world – things that move or bite or provide sustenance or have minds like our own– possibly helped our species out-compete rival lineages, infer other’s thought processes to avoid or approach them, and so on, to say nothing of tool-making and culture. And for the sake of brevity, which this reply already ignores, we have an unbelievably vast array of evidence from the sciences that crank up the microscope even more. Relating the genome to neurons to circuits to behavior is the new standard in modern neuroscience. As a result, a vivid picture of what’s causal and what’s not unfolds.
And so, consciousness becomes a tractable problem when you truly accept that 100 billion of these specialized cells sufficiently and necessarily represent the world from without and the world from within. Antonio Damasio does a fantastic and comprehensive job explaining the brain systems involved, necessarily and sufficiently, in the process of consciousness in his book, The Feeling of what Happens. There’s simply no need to invoke concepts of non-locality or primordial grounds, soul or some mysterious universal ether, because unless those concepts are providing real, tangible pressures on the brain’s activity, then they cannot impinge on or even influence its normal functioning. There’s also not one bit of evidence for them.
Matter is Mind is Matter
The beauty of a hypothesis (such as Crick and Koch’s) that claims consciousness is the product of neural activity and neural activity only is that it is falsifiable with an N of 1, and that 1 simply has not been found. An overnight Nobel Prize goes to the person who finds it, but given how much we actually know about how the brain achieves the mind, that specific award will forever remain collecting dust. I take for granted that the mind bubbles up out of inert matter because no observation has ever suggested otherwise. More importantly, inert matter, such as single hydrogen atoms, do seemingly magical things when given nearly 14 billion years to interact, decay, explode, form stars, form planets, form lipid bilayers, form replicative machinery…. form minds, form life.
I also take for granted that life bubbles up out of inert matter because this can be tested and even understood if one goes through evolution in a step-by-step manner. Life’s humble beginnings were a series of thermodynamically favorable interactions between lifeless phospholipids (see Harvard’s “Origins of Life” project, and for a completely disheartening failure at science, see this), and the humble beginnings of conscious thought can also be understood in terms of step-by-step neural organization and complexity across species.
As I’ve said before, as neuroscientists, we can stimulate certain parts of the brain stem and increase or decrease breathing rates and heart rates; we can record from various memory-related brain regions and decode and reconstruct the signals as a specific memory; we can even turn neurons on and off with light on a millisecond timescale in only certain cell types and still get a resulting phenotype, a change in behavior. In short, we’ve altered the structure and function of the mind, and this includes both human and animal work.
To Ronan: it is possible to electrically record global brain activity or single neurons in vivo and in humans, specifically epileptic patients who often give consent prior to brain surgery. Also, brain stimulation in humans can cause (read: cause) all sorts of changes in behavior – from arm movements to changes in our opinion regarding a moral dilemma. The entire field of neural prosthetics is dedicated to the idea that the mind is produced by the electrochemical communication between neurons, and that we can mimic this activity artificially to restore a wide array of neural functions. Your conscious thoughts really, and I mean really, are “just” the sum total of patterns of neurons firing.
Consciousness surely is not an exception — why should it be? As I wrote in my previous post, just because we hold consciousness near and dear – what more personal topic is there than our ability to introspect? – this does not render it immune to scientific scrutiny and full understanding. I make such claims wearing a white lab coat because the standard of modern scientific evidence is so rigorous and precise that it would be a tragic disservice not to. A person’s (mis)understanding does not necessarily depend on how many “evident facts” they know – it depends on their ability to properly interpret a finding independent of their emotional state.
Research Happens at the Edge of What is Known and Unknown, and Consciousness Belongs to the Former
In other words, I take my stance on consciousness not because I wish it so, but because the overwhelming evidence in its favor would make any other view buckle at the knees. Yes — science is provisional, but there are general, grander claims that simply are fact. The details are provisional. I assume you accept evolution by natural selection. Evolution, for example, is an irrefutable truth explained by the provisional process of natural selection. The latter’s details can ebb and flow; the former has become experimentally unassailable.
Analogously, it is the details of consciounsess (“What brain regions are involved… how does a neural system represent information about the self… what genes are involved in forming these neural systems during and after development?”) that are being worked out; the overall framework of consciousness being a product of neural activity is, and shouldn’t be, questioned anymore. Think of how you feel when someone questions the feasibility of evolution, or of the earth’s roundness; that is how we feel when someone questions the feasibility of neurons being responsible for consciousness.
Yet, to use evolution again, much of your argument sounds like the anti-Darwinists who loudly gasp “So – where are all the transition fossils, the ‘missing links,’ that show the intermediate between fish and amphibians?” All it takes is a trip to any natural history museum to see the, literally, hundreds of thousands of transition fossils in support of evolution. Similarly, all it takes is a trip through a neuroscience lab, or the right book, or the right paper, or the right argument, to get a feel for what 100 billion neurons are capable of. Any claim suggesting that brain activity alone is not necessary and/or sufficient for consciousness is simply wishful thinking. The brain looks very different to you from the standpoint of neuroscience.
I am not, however, claiming that we are the only privileged few capable of understanding the brain. Half of our job is to disseminate that information properly, hence this response. One needs only to look at the patterns of history to appreciate my point: humanity shrugged in disappointment when the earth became round. It collectively sighed when our galaxy became one out of a hundred billion billion galaxies. It got goose bumps when staring at a chimp meant staring at a cousin.
And now, it has receded to the world within, the mind, which from the standpoint of science is no different than the world from without. Humanity has withheld that assumption for the past 2500 years, though this changed in the early 1900s when Ramon y Cajal finally began to pick the brain apart. To say that reality is made of mind or matter is a misnomer and it is the unfounded illusion (and delusion) I am trying to dispel; for, not a scrap of evidence has been unearthed to falsify the claim that the mind is made of and produced by neurons and neurons only. The onus is on the maker-of-the-claim to prove it so.
Altered States of Consciousness
I meant it when I said modern neuroscience could “do better” – and here’s an example we can all relate to. Drinking alcohol or smoking pot has its effects on the brain and alters your state of consciousness because of how it alters the patterns of neural firing. When you drink alcohol it increases the expression of a molecule called GABA, which for the sake of simplicity, inhibits neural firings. Your frontal lobes are largely responsible for actively inhibiting a particular action (e.g. refraining from throwing your phone after a dropped call). GABA inhibits this region to a large extent – thus disinhibiting your actions and making it more likely that you’ll say things you didn’t mean, do things you wouldn’t have done otherwise, and so on. It also inhibits your cerebellum – an area partly responsible for your ability to generate fine-movements. And after making its way to your brainstem, GABA can depress breathing rates (which is a large reason why binge drinking can lead to death, because the person may not throw up in their sleep, but he or she may simply stop breathing.)
With an upregulation of GABA, you stumble and mumble and breathe drunkenly. And this is just a cross-section of one substance in the brain producing or affecting all sorts of behaviors; do keep in mind that a normal brain entails the parallel action of millions of molecules acting on billions of neurons. And all of this is traceable on the level of genetics, neurons, circuis, and behavior.
I ask again, why should consciousness be any different? Mental phenomena are neither illusory nor emergent; so on what basis do you claim that consciousness is not a type of behavior? To go back to Crick and Koch, their research bridges the visual sciences and consciousness by asking what structures of visual cortex send projections to pre-frontal cortex, anterior cinculate cortex, and insula – a property they consider essential to consciousness, as it endows us with the ability to hold information, even information about ourselves, over extended periods of time.
A Reality Check
“But as to how this neural activity is related to experience, their theory tells us nothing.” With all due respect, Matt, that claim is demonstrably false. Crick, Kock, and most scientists who are tackling the various aspects of consciousness relate neural activity to experience in the following manner: they argue (rightfully) that our ability to experience and re-experience life is largely contingent on the integrity of our frontal lobes. The rich, colorful environment we experience is nothing but your brain cells doing what they do best – representing information over time. This is one “Nothing But–“ statement we are absolutely sure of. As such, the “inconsistency” you point out evaporates with the proper explanation; science has applied irreparable heat to solipsism.
Indeed, science is at the point where it can begin to answer questions such as, “How and why did the Big Bang happen? How and why did life begin on earth? How and why are we conscious?” and so on, virtually ad infinitum. We undoubtedly need both science and philosophy in tradition and in practice – that much is not up for debate, because philosophically-informed science provides logical frameworks for experiments, while scientifically-informed philosophy can turn a thought-experiment into a hypothesis-driven truth claim. But if science is stepping on the toes of what was once the realm of philosophy, then philosophy had better wear steal-toe boots. This is what motivated Stephen Hawking to freely proclaim, “Science will win, because it works.”
Beyond our Sensational Horizon
As for your last claim, we do know an enormous amount about the physical world outside our “contingent physiology”! We expand our visual field with infrared goggles, x-ray detectors, and microscopes; we tune our ears in to all sorts of radio frequencies previously undetectable. Scientific knowledge is not by any means shaped merely by the “contingency of our organs of perception,” because we have myriad tools that enable us to pick the world apart beyond what are 5 senses would normally let us.
The tools are emotionless data-measurers because, as humans, we are emotion-filled, flawed, biased data-collectors. The tools of science filter out that bias. Yes – we do use our senses nonetheless to analyze the collected data, but the data were collected by machines that distinguish what is really true from what humans want to be true. Physicist Richard Feynman was spot on when he said, “The first principle [of science] is that you must not fool yourself, and you are the easiest person to fool.” Science removes our natural urges to fool ourselves — much is contrary to reason, nothing above it.
Also, saying that our ethical responsibility would be undermined in light of objectifying consciousness is like saying that all things are fair if God is dead. There is a growing body of science in support of the view that humans have an internal moral compass, independent of our cultural backgrounds (Despite his unfortunate academic debacle, Marc Hauser still offers a substantial review on other scientists’ evidence for an “innate moral grammar”. Sam Harris, too, ruffles the feathers of philosophical branches by arguing that science can objectify morality, and these claims are independent of whether or not we truly have “free will.” Here his provocative Ted Talk).
I should note that because we can explain consciousness on purely physical terms does not mean we’ve explained it away, and we also haven’t done much damage to free will. If free will is defined as our ability to choose otherwise, then it is the very structure and function of the human brain within the framework of evolution that enables this ability (See Dan Dennett’s Elbow Room: The Varieties of Free Will Worth Having), as evidenced when these structures and functions break down. However, if you’re a quantum physicist and live in a deterministic world, then free will is an illusion at best, and there’s no escaping this. But when translated into neuroscience, free will becomes an act of choosing, regardless of whether or not it is an illusion. Calling it an illusion does not mean it doesn’t exist, it simply means it fools our cognitive machinery very well. We do still experience illusions, after all. No one denies their reality.
What is Science, and When Does it Achieve Escape Velocity?
To end, I will hold your claim (i.e. “Reality is a relational process whose features [psychical and physical] are continually brought forth out of a primordial, non-substantial creative ground”) to the same rigorous process that mine are held to: Is there evidence, and what would the evidence look like? Can you be wrong, and how would you know you were wrong? Can you measure it, and what measures would you take? Does it make testable predictions, and what would they look like?
If you can answer these four questions in the affirmative and provide an example of each, then your claims become science – that is, they become empirically testable and, ideally, can actually be shown to be a part of reality’s fabric. Faith or belief, in this instance, just doesn’t come close to cutting it. I don’t think that science is in a rush to crown itself the queen of human knowledge – by virtue of its own success, it does not need to be in a rush at all. As Neil DeGrasse Tyson quips, the enterprise of science should simply be renamed Reality.