The annual Toward a Science of Consciousness conference, organized by the University of Arizona’s Center for Consciousness Studies, recently dropped the “toward” in changing its name to just “The Science of Consciousness.” Why? Well, longtime conference organizer and human wrecking ball Stuart Hameroff feels that 22 years after the first conference the science of consciousness has advanced far enough to warrant being called a real science.

Many others agree as more and more scholars jump into the deep psychological, neurological and philosophical questions of consciousness. What was for a long time a somewhat fringey field is now quite mainstream, and there is no shame in talking about the “hard problem” of consciousness among even the most hard-nosed of scientists.

The hard problem is the newer name for the ancient mind/body problem. While there is still no widely accepted solution to this conundrum, various efforts are making real headway in the halls of academia and beyond, including theories like Tononi’s Integrated Information theory, Dehaene’s Global Neuronal Workspace theory and Hameroff’s own (with Penrose) Orchestrated Objective Reduction theory or Orch OR. (My own contributions to this field can be found here and here.)

Eric Schwitzgebel is a philosopher at the University of California at Riverside who has specialized in the study of consciousness and, in particular, how bad we humans are at introspecting about our own consciousness, among other things. He wrote Perplexities of Consciousness in 2011, a collection of essays about the puzzles of human consciousness. He blogs at the Splintered Mind.

Even though Schwitzgebel is a philosopher, he’s not shy about wading into scientific waters, including in cognitive science, which is the main topic area covered in this interview.

I interviewed Eric by email for my upcoming book, Deep Science: Further Essays in Philosophy, Science and Spirituality.

Tam Hunt: How do you define consciousness? Why does it matter to people who don’t make a living reading and writing journal articles, or the occasional blog post?

Eric Schwitzgebel: Consciousness, or conscious experience, is the stream of sensory experiences, emotional experiences, and conscious thoughts and imagery that we all experience most of the time. It’s your experience of what you see when you open your eyes and what you taste when you have a sip of tea. It’s what you experience when you close your eyes and think about going to the beach. It’s the sudden rush of anxiety you feel when a car swerves your direction on the road, or your feeling of quiet contentment as you relax after a long day. If you care about experiences of this sort — and of course you do! — then you care about consciousness.

TH: What is your philosophical orientation on the hard problem of consciousness, more generally known as the mind/body problem?

ES: Some beings clearly have conscious experiences: human beings, of course, and presumably most other animals with sophisticated brains. Other entities presumably do not have any conscious experiences: chunks of granite, bacteria, your laptop computer. What exactly is it that the former have that the latter lack, so that the former have consciousness and the latter don’t? Although many theories have been proposed, by both philosophers and scientists, there seems to be no good way to adjudicate among those theories.

TH: Do you have any doubts about materialism providing the best answer(s) to the philosophical problems of consciousness?

ES: If I had to place a bet on one broad type of approach to consciousness, I would bet on materialism, which is the view that everything in the universe, including our conscious experience, is ultimately composed of matter and energy, or forces and fields, of the sort described by fundamental physics; and in particular, materialism denies that there are immaterial souls of the sort posited by some religious theories.

Despite my materialist inclinations, however, I don’t think we can rule out alternative views. The main competitors are substance dualism (according to which there are immaterial souls in addition to material stuff), idealism (according to which there are only minds and their experiences and no mind-independent material world at all) and various views that compromise among these alternatives or reject all three alternatives.

Here’s one form of idealism: Maybe we are all just ideas in the mind of God. How do we know this is not so? Although that wouldn’t be my first guess about the nature of the universe, it does have a certain elegance as a basic cosmology, I think. This is not the kind of view that we can show to be false by building a large enough particle accelerator or an accurate enough brain imaging device. We can only evaluate this type of claim in a less straightforward way, and I think a certain amount of agnosticism about such matters makes sense.

TH: Which of the various modern and debated materialist theories of consciousness do you think have the most promise? And why have none of these theories gained very broad support yet?

ES: I’m afraid I’m skeptical of them all! I don’t have a favorite. They all seem to have tradeoffs of various sorts and to rest on assumptions that I don’t think we’re really in a position yet to evaluate.

TH: You’ve criticized in a series of blog posts and a scholarly paper a number of approaches to consciousness as providing insufficient boundaries for the types of conscious entities that can potentially arise, which is a long-standing issue known as the “boundary problem,” including Giulio Tononi’s Integrated Information Theory (IIT) of consciousness. IIT has gained a lot of attention in recent years. What is the heart of the boundary problem, and why is it so tricky to solve?

ES: An interesting question about consciousness — sometimes called the “boundary problem” — is why are you conscious but not several subparts of you (say this part of your brain here and also, separately, this other part of your brain over here)? And why don’t groups of people interacting together seem to give rise to a separate stream of conscious experience at the group level? We normally think that the locus of conscious is either the individual organism or the individual brain and not anything higher or lower.

But it’s unclear why we should be as confident about this as we normally are. Consider a large group of people, like the United States. Think of the United States in the way a planet-sized alien might: as a concrete, spatially-distributed entity with people playing roles somewhat like the roles that individual cells play in your body. This entity imports bananas, exudes smoggy waste, extends a pseudopod to invade Iraq, monitors its borders, flexibly protects itself. It does lots of internal information processing, in all kinds of fancy self-regulatory loops! It appears to be no less intelligent than, say, a hamster. It meets the criteria for consciousness on most materialist theories, if those criteria are straightforwardly applied. So why don’t we think it’s conscious?

One possibility, which I take seriously, is that the United States really is, in fact, conscious — in other words, that it has a stream of real experience, though one presumably very different from our own. Another possibility is that it’s not conscious; but then it’s not clear by what criteria it should be excluded; nor how confident we should be in saying that it’s not. Do we have a “conscious-ometer” that we can put up against the side of the U.S. to prove that it’s not conscious? We say that it’s not conscious because it’s contrary to common sense to think that it is conscious. But how reliable a guide is common sense in matters such as this? Common sense has not done very well in scientific physics or scientific biology, so why think it should do any better as a guide in the science of consciousness? Maybe this is one of the issues on which it fails?

Similar issues arise when we consider subsystems of the mind. For example, consider the neurons in your gut that help regulate digestion. The “enteric nervous system” has got a few hundred million neurons, about as many as an insect. Might it enjoy its own kind of independent consciousness?

TH: Specifically, with respect to IIT, you argue that Tononi’s “exclusion postulate,” which is his solution to the boundary problem, is itself problematic and ad hoc. What’s your beef with this approach?

ES: Tononi’s 2004-2008 version of IIT seemed to allow for group consciousness, that is, consciousness in collections of entities that are themselves individually conscious. He expressed some hesitation about this starting in 2009, and then in 2012 he revised his theory by adding an “exclusion postulate” specifically to exclude group consciousness and subsystem consciousness. The exclusion postulate says that conscious systems can’t nest in each other or overlap. Whatever system has the most “information integration” (mathematically defined) is conscious, and no subsystem, larger group or overlapping system can simultaneously be conscious. Although this postulate saves common sense intuition by ruling out group consciousness, it has some other bizarre consequences. One consequence that I have emphasized in my critiques is that as soon as a group becomes sophisticated enough to integrate more information than the amount integrated by any of its members, then all of its members suddenly become unconscious — and they could in principle do so without any change in their behavior, including in their introspective self-reports.

TH: This is, I agree, an apparently serious problem with IIT if we have a strong intuition, like most of us do, that collections of entities don’t have an independent and higher-level consciousness. Is there any solution present for either IIT or other approaches to consciousness?

ES: I wish Tononi would drop the exclusion postulate, go back to the version of IIT from 2004-2008, and accept that there are low levels of consciousness in groups and subsystems. He already accepts that small systems that aren’t parts of larger systems have a low level of consciousness, so why not just apply that everywhere? It’s a bizarre view by the standards of common sense, but I would argue that any well-developed theory of consciousness is going to sharply violate common sense somewhere. Also, it’s a dubious view, but as I skeptic about theories of consciousness I think all the competing views are dubious. And it has considerably more theoretical elegance, in my opinion.

TH: Given the difficulties you and others have presented with respect to the boundary problem (also known as the combination problem), what are we to do? Do we simply shake our heads in deference to the mysteries of the universe, or do we perhaps need a more radical approach?

ES: In my judgment, the best approach is to recognize that the tools we have for addressing these issues are highly limited and flawed. We can appeal to empirically obtained scientific evidence, but that can’t really address the biggest theoretical issues in any direct way. We can appeal to abstract virtues like simplicity or elegance, but those are generally indecisive among well-developed alternative theories. And we can appeal to our background cultural views and common sense, but those are unreliable as grounds for scientific theorizing on questions outside the run of ordinary life. But still: Some theories are clearly better than others. Our tools aren’t useless. The view that we have an immaterial soul for exactly 17 seconds starting on our 18th birthday has no merit by the standards of empirical science, common sense or theoretical elegance. We can make some assessments by means of these flawed and limited tools. Hopefully, we can make some progress. But we ought to recognize our limitations.

One advantage of recognizing our limitations is that it encourages our sense of wonder. Maybe we are all ideas in the mind of God! How weird and awesome would that be? I think the impulse to search for a radical new approach that will cut through all the puzzlement with a single profound new insight is exactly the wrong impulse to have here.

TH: Shifting gears a little, as a philosopher, how do you view the separation (if there is one) between philosophy and science? For example, you as a philosopher are critiquing theories that are explicitly scientific in their approach, like IIT, and you are taken seriously even though you’re “just” a philosopher. Do scientists and philosophers have a tendency to place too much credence in their institutional and professional boundaries?

ES: Academics love disciplinary boundaries. There are so many people who claim knowledge of your favorite topic if your favorite topic is one of broad interest, far too many people to read or seriously assess — including people working in other academic areas who make pronouncements about what you think of as your turf. So how do you cut it down? There has to be some credentialing system.

I think interdisciplinary work is incredibly valuable. It’s what I do. My whole career has been about finding connections between philosophy and other disciplines, especially psychology. But I understand why people in other disciplines would be skeptical. The only way to overcome this skepticism is to really do the work, learn their tools, master the relevant literatures, develop approximately a Ph.D.-level of skill in their discipline (which of course takes years of labor), and prove yourself to them again and again.

If you do that serious work, you will find interesting connections, for sure. Your mind will operate differently than most of your colleagues’. It will spin out of the ruts, out on to fresh paths.

— Tam Hunt is a lawyer and owner of Community Renewable Solutions LLC, a renewable energy project development and policy advocacy firm based in Santa Barbara and in Hilo, Hawaii; co-founder of Solar Trains LLC, and author of the new book, Solar: Why Our Energy Future Is So Bright.​ Click here to read previous columns. The opinions expressed are his own.

Tam Hunt is a lawyer and a writer. The opinions expressed are his own.