On the Mystery of Consciousness

EXCELLENT BEAUTY T H E N AT U R A L N E S S OF RELIGION AND THE U N N AT U R A L N E S S OF THE WORLD

ERIC DIETRICH

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calism about consciousness is quite possibly false. And in any case, the evidence for it is far too weak to grant physicalism the status of a confirmed scientific theory. Let’s look more deeply into this matter. The result will be an appreciation of consciousness’s profound weirdness.

I T I S A S I M P L E , B R U T E F A C T that early-twenty-first-century science doesn’t know what neural processes consciousness is associated with (I’ll use “science” as a catch-all term to denote neuroscience and psychology and any other science one might care to deploy in the quest to understand consciousness, like quantum physics). The list of candidates proposed by scientists to explain consciousness is embarrassingly large. Here are some of them: attention, autobiographical memory, being awake, body-based perspectivalness, episodic memory, executive processing, feedback, feature integration, 40 Hz neural oscillations in human brains, high-level encoding, intentionality (as in intending to do something), intentionality (as in a thought’s content or its being about something in the world), metaprocessing, mind-based perspectivalness, neural competition, quantum effects in the microtubules of neurons, recursivity, reflective self-awareness, reportability, salience, and sense of self.

It is rare in any science of any type to have such a long list of hypothesized causes of some phenomenon. But the truly alarming thing about this list is not how long it is, but how diverse it is. It contains proposed hypotheses that are themselves deeply mysterious and so of no help at all (for example, sense of self), along with actual measurable neural processes (for example, 40 Hz pulses), along with actual measurable psychological processes (for example, episodic memory), along with some very eyebrow-raising physics (for example, quantum effects of the microtubules of the neurons in one’s brain)—all of which have so far produced no viable theory of consciousness.

But, in truth, everything on this list is a waste of time: science cannot touch consciousness. The list of things about consciousness that we cannot explain is not just huge—it is absolutely every single thing associated with consciousness. Scientists cannot explain at all how the five senses work to produce sounds of ocean waves or visions of the color indigo. Scientists know how to numb neurons for light surgery and, for more serious surgery, the anesthesiologist can put you to “sleep.”

But no scientist anywhere knows why the gases and chemicals remove

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consciousness, either in part or more completely. We don’t even know why aspirin makes headaches go away.We know it works, and we know in some detail what aspirin does, neurochemically. But we don’t know why those neurochemical reactions are or cause the cessation of pain.

Neurochemical knowledge is essentially pointless when it comes to explaining experience. No one knows why whisky or wine or any other such chemicals have the effect that they have. No one knows why LSD or marijuana do what they do. No one knows why love or orgasms feel the way they do. No one knows how neural processes produce sadness or grief. No scientist knows why Prozac or Xanax or any of the drugs used to treat any mental illness or condition do what they do. And no one knows what neural processes produce joy or ecstatic spiritual knowledge. Again, much of the neural chemistry of all of these is known; scientists know a great deal about how these chemicals work on the neurons in the brain and the rest of the body. But all this neurochemistry is useless for explaining why these chemicals have the effect on conscious experience that they have. These experiences are what matter, and we cannot explain them.

It is not that scientists don’t know vast quantities of stuff about neurons, neural architectures, neural processes, brains, psychological processes, psychological states, and so on. They certainly do: attend a neuroscience conference or read an issue of Science and you’ll quickly find out how much they know; it’s immense and very technical. For example, they know much about the neural processes underlying vision, hearing, smelling, tasting, and touch. But they are clueless about why those neurons, those neural processes, produce the conscious visual experiences that they do. No one knows why neural firings produce pain, nor why a headache hurts differently from a punch in the face.

The anesthesiologist knows tons about what the gases and chemicals she’s putting into you do to your neurons and brain. But she has no clue at all about why doing those things to your brain and neurons makes you lose consciousness to such an extent that a heart surgeon can open up your chest while you lie perfectly still. No clue. And I am not exaggerating one whit; I’m being literal and precise.

Contrast this with cars. It would be strange indeed if mechanics knew a ton about how cars are put together, but didn’t know why turning the key in the ignition started cars. They in fact know in detail why turning the ignition key works. And some know what’s going 120

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on down to the electron level. That’s good if you own a car, especially one that’s not starting. More deeply, it shows what human knowledge can accomplish. That we can know something so thoroughly is one of the very best things about humans. But human knowledge can’t touch consciousness.3 You are probably dubious. Surely, you say, if science can’t explain consciousness now, it will eventually, perhaps even soon. Perhaps you even think that nothing is intrinsically beyond science’s purview. I’ve had many a discussion with cognitive scientists and neuropsychologists who of course agree that science cannot now explain consciousness, but who think it will before the next decade (next fifty years, next century) is over. (Different researchers provide different lengths of time.) I call this the “just wait until next year” claim; it should be called the “just wait until next year” blind faith. Just wait until next year. . . . we can wait until the next millennium for all the good it will do.

Here are two intuition exercises (similar to thought experiments) to show that consciousness is beyond explaining. As luck would have it, there are two very popular movies that make this exercise fun.

The first will exercise what is called your Cartesian intuition (named after René Descartes). This is the intuition that your conscious experiences could be just what they are no matter what the world is really like. I am confident that you have this intuition; it is well known that most people have it. The famous movie The Matrix is founded on exactly this intuition, and in fact is an extended, multimillion-dollar celebration of it.

In the movie, the entire human population is really living out pathetic “lives” encased in billions and billions of underground coffins filled with some sort of life-sustaining goo. Each hairless body in each coffin is attached to a world-sized computer that directly gives all of our brains the experience of living our lives on the real surface of Earth sometime around the turn of the second millennium ce (common era).

The “reality” we all know and love—life on planet Earth—is entirely simulated: no one has even once actually used his or her eyes, or any other sense organ, to sense anything. We are all in one large, collective computer dream. In the twenty-first century, we could call this the Matrix intuition, but the famous philosopher René Descartes (1596–1650) beat the Wachowskis to it (by a few years). Descartes imagined an evil demon manipulating our senses (note: not our sense organs [for these 121

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are physical things we believe we have] but the actual conscious experiences associated with our five senses) in various ways in order to deceive us into believing that we have human bodies and are walking around doing things. In fact, we have no bodies at all. Reality as we conceive it is an illusion. In his Meditations on First Philosophy, Descartes describes this demon thusly: “as clever and deceitful as he is powerful, . . . [he] has directed his entire effort to misleading me.” Why would such a demon spend his life (or eternity) doing such a thing? Why because he is an evil demon. (In The Matrix, the builders of the matrix have a much better reason, it turns out.)

(There’s a tiny wrinkle we need to discuss. I claimed that Descartes said the evil demon manipulated our senses, not our sense organs. He was careful about this because, in truth, we may not have sense organs, or at least not the ones we think we have, if the evil demon is fooling us. A good way to imagine this is to think that we are just nonphysical, disembodied spirits—ghosts—being fooled by the demon. But in The Matrix, humans in fact have human bodies; it is our brains and sensorimotor systems that are being stimulated in the right way to fool us into thinking we are reading a book on religion and scientific mysteries. The Matrix is a lot more believable nowadays, a lot more easy to imagine, than Descartes’s disembodied/evil demon version [in fact living in a matrix may well be in our future, if AI and research into virtual realities unfold in a certain way].4 We have trouble with the disembodied version because we tend to think of the evil demon as using some sort of physical apparatus on us, and we find it hard to imagine causally affecting something nonphysical [our ghost selves or our spirits] with something physical. But perhaps the evil demon isn’t using something physical on us. He/she/it is using something nonphysical, perhaps magic. If that works for you, great. I invite you to use either The Matrix or Descartes’s evil demon version to pump up your Cartesian intuition. Either will work fine.)

The Cartesian intuition is easily and naturally held simply because we all dream at night. You are hang gliding in the beautiful Himalayas . . . but no, you are asleep in your bed, dreaming. Perhaps you have never hang glided in Himalayas, or perhaps you’ve never hang glided anywhere. Perhaps you don’t intend to; perhaps you don’t even want to. But there you are anyway—soaring between Chomolungma and Nuptse. But dreams aren’t “real.” So we all know that we can easily 122

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experience something quite robustly even though we aren’t “really” doing what it takes to actually have that experience (for example, we aren’t actually hang gliding in the Himalayas).

The Cartesian intuition, then, sunders the connection between the world and your experiences. Or at least it shows that the connection between your experiences and the world is tenuous. You can experience anything, yet be doing basically nothing.You are not now actually reading this sentence, using physical paper and ink, and light, and your eyes. . . . No, you are encased somewhere in some vat of goo, being duped into thinking that you are actually reading this sentence. Or perhaps you are dreaming that you are reading this. Perhaps you are a computer, dreaming that you are a human reading about mysterious spiritual journeys.

Of course, it is next to impossible to believe for any length of time that you are actually in a vat of goo in the matrix (or asleep in your bed or whatever). You think you are in the world, living your life, reading this sentence. This is a perfectly rational belief—if you didn’t have it, you’d probably be in a hospital somewhere being treated for some sort of mental illness. What the Cartesian intuition shows is that, though perfectly rational, your belief that you are living your life in the world is in fact a leap of faith—the connection between your experiences and the causes of those experiences is nowhere near as tight as you think.

In fact, as far as you know, there’s no connection at all.

Though the Cartesian intuition discombobulates matters considerably, we can discombobulate matters further. To completely sunder the connection between consciousness and the world, we can assume that life is really as we experience it, that there is no matrix, and that our brains are filled with neurons . . . just as it seems. Now, we will work to imagine neurons doing their neuronal thing with no consciousness at all. We will clearly and cleanly imagine a being of some sort living a robust life, traveling hither and yon, doing this and that, with neurons abuzz, yet with no consciousness at all. This is where the second intuition exercise comes in. And the second movie.

Philosophers have a technical term for creatures that have bodies— neurons, brains, and sense organs—but experience nothing: zombies.

Zombies are very important in philosophical discussions of consciousness, because they seem to show that one can be fully embodied and alive and yet completely inert on the inside. (I don’t mean inside their 123

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skulls: zombies’ neurons work perfectly well. By “inert on the inside” I mean zombies lack a self that is the locus of conscious experience.

Note: philosophy zombies are very different from monster zombies portrayed in popular fiction.) To use Nagel’s phrase: there is nothing it is like to be a zombie—or, using a slight variation, being a zombie is just like being a doorknob: experience-less.

Well, how easy is it to imagine zombies? Can one legitimately imagine them? The zombie intuition, the intuition that zombies could exist here and now on planet Earth, is not as easy to come by as the Cartesian intuition. Fortunately, Hollywood has helped out here, too.

In Pirates of the Caribbean, Captain Barbossa and his mutinous band of miscreants are cursed men. After stealing quite a bit of sacred Aztec gold (which had had a curse placed on it by the Aztec gods—understandable given Cortez’s behavior), Barbossa and his men discover that though they can feel profound, gnawing hunger, choking thirst, and consuming lust, they cannot in any way satisfy their cravings. In fact, they can’t feel or sense much of anything, not the wind on their faces, nor the smell of the salt air. They can only feel the three desires just discussed and pain.

Come to find out, though by day they seem to have bodies and skin and organs, in the light of the full moon, one can see what they really are: corroding skeletons.

Barbossa is not a zombie . . . not quite. He can still feel some things (and of course, he doesn’t have neurons, at least by the light of the full moon—we will let that slip, however). But we can use Barbossa to construct a zombie, a zombiefied Barbossa. Here goes. . . .

Let us first assume that Barbossa can feel nothing at all. He forces Ms. Turner to take off her dress before he forces her to walk the plank (never fear, Pirates is rated PG-13, so Ms. Turner remains fully clothed at all times, in a totally modest undergarment of some sort). He leeringly says of the dress, “Mmmm . . . still warm . . .” When he does so, he (Barbossa) cannot actually feel the warmth still in the dress. So how can he correctly say, “Still warm”? Well, his body can still process the information that the dress is warm, much like a thermometer could.

Thermometers aren’t conscious (as far as we know), yet they accurately register temperature. Barbossa’s bodily heat sensors work like that.

Though one can carry on a conversation with Captain Barbossa— he seems to see and hear you and responds accordingly—we can easily assume that he doesn’t have any visual or auditory experiences at all. His 124

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sense organs (such as they are) process the information that exists in the relevant light and sound, and Barbossa’s body (mouth, tongue, and vocal cords, for example) produces the right output . . . but during all of this, Barbossa experiences nothing. His ears pick up sounds like microphones, his eyes pick up light like cameras. Mechanisms process this information, but no experiences ever happen. The same is true, let us suppose, of smell and taste. Both of these work like chemical analyzers, checking for various chemicals and outputting the correct response, but no experience accompanies this information processing and this response. (In the movie, Barbossa can experience taste: referring to himself he says everything tastes of ashes. But let’s suppose that his taste experiences have also become zombiefied; he can taste nothing.)

So, all five of his senses work just like some unconscious machine or device: thermometers (and various pressure-sensitive devices) for touch, microphones for hearing, cameras for vision, and chemical analyzers for smell and taste. On the inside, Barbossa’s experiences are only hunger, thirst, lust, and pain. He doesn’t even experience darkness.

Now, if we remove his feelings of suffering—the hunger, thirst, lust, and pain—we get our zombie (in the movie, some of Barbossa’s pirates seem to experience pain when stabbed or hit). So, Captain Barbossa can be rendered as a philosophy zombie: a perfectly physical being who behaves in all the right ways all the time, just like you and me, but who is utterly inert on the inside. There is nothing it is like to be our zombiefied Barbossa. In fact, in many ways, it is far worse to be the actual Barbossa than the zombiefied Barbossa, since the actual pirate suffers hunger, thirst, and lust. (C3PO and R2D2 [from Star Wars] and Commander Data [from Star Trek: The Next Generation] might possibly also help you imagine zombies, but this is unlikely, since what really happened in those shows was that we all became convinced that robots [androids] could in fact be conscious. This intuition is just the opposite of the zombie intuition.)

Still, you might be reluctant to grant that Barbossa, or any zombie, could behave perfectly correctly and yet be unconscious. I have an ace up my sleeve that will answer this reluctance.

For all you know, your spouse, partner, best friend, dog, cat, and so on could be a zombie. Try this. Pick out someone near you now (actually, it helps if you pick out a stranger), and imagine that that person is an experience-less zombie, an unfeeling, conscious-less android of 125

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some sort, capable of all the right behavior but utterly inert on the inside. Imagine that there is nothing it is like to be the person you picked out.You know they behave appropriately, but you don’t know that they are conscious. The same is true of you and me: your consciousness is unavailable to me, and mine is unavailable to you. Consciousness is entirely and forever internal and personal. Your heart is internal, but I can make it external—heart surgeons do this routinely. Consciousness is forever internal to one person, particular to that person and that person only. This isolation gives rise to what philosophers call the problem of other minds: a person with a conscious mind, me for example, doesn’t know for sure that there are other conscious minds in the world; there might only be zombies. The problem of other minds arises when we come to the conclusion that behavior isn’t sufficient for knowledge that someone else—anyone else—is conscious. (Actually, the problem is more acute than doubting the consciousness of others, which is bad enough; others may also not have any thoughts at all, conscious or otherwise, for example, the thought “oh, it’s time to walk the dogs.”

Everyone else may be very sophisticated puppets of some sort. We will skip this more virulent version of the zombie intuition.) We see that consciousness (and the mind in general) is very peculiar. Its hallmark is utter and eternal isolation.

So, given everything you know about someone else—which is all derived from his or her behavior—that person might not have any consciousness at all. The person you are closest to, the person you love the most, might be a zombie. Your consciousness might be the only consciousness in the entire universe. Or perhaps my consciousness is the only consciousness in the entire universe. I can only be certain of my consciousness. From my perspective, which is the only one I am prepared to swear to, all the rest of the animals on planet Earth might be zombies.This isn’t solipsism (which is the view that only I exist), but it is disturbingly close, probably too close.

I want to stress that for all you know, your own true love is a zombie. Note that it is impossible to prove that your spouse, say, is a zombie, just as it is impossible to prove that he or she is not a zombie. Imagine if someone asserted that you were a zombie. How would you refute them? Drop a bowling ball on your foot and then cry out in pain?

Zombies can mimic this behavior exactly. Eat some yummy chocolate ice cream and say, “Yum?” Zombies can do that, too. State that, 126

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upon reading Excellent Beauty, you find consciousness to be mysterious?

Again, easily replicable by a garden-variety zombie.

Zombies, then, demonstrate that physical processes (for example, neural ones) can go on without consciousness existing at all. Zombies finish what the Cartesian intuition started: consciousness is now completely sundered from the physical.Your conscious mind is now shown to be independent of the world it inhabits and even of the very neural processes it seems most closely associated with. I’m not saying that you can believe this conclusion on a day-to-day basis. You will find it impossible to believe for any length of time that this book you are now reading isn’t really out there, in your hands, causing your book experiences. But I am saying that for brief moments of time, you can see that your consciousness could well be utterly independent of any world you think is out there. In fact, there need be no world out there at all.

Now, it is easy to see that consciousness is mysterious indeed. But we aren’t done with consciousness yet.

I said that human knowledge can’t touch consciousness. I meant that external, third-person knowledge can’t touch consciousness. In one very important sense, human knowledge not only can touch consciousness, human knowledge is constituted by it. Remember that your conscious experiences are forever beyond me. But they are you. You know nothing as securely as your own conscious states, your own experiences.

Your consciousness, in fact, is the most important thing about you, for if you weren’t conscious, if you were a zombie, then there is an important and real sense in which you wouldn’t exist. That your physical body exists is the second most important fact about you. As I mentioned, your consciousness—the fact that there is something it is like to be you—is what makes your life worth living, or what makes you want to die right now, or quit reading and go get a sandwich. In fact, in some way that—big surprise!—no one understands, consciousness gives rise to or is somehow intimately associated with your ability to use language to mean and communicate things, to have knowledge, and to be moral.

So, of course, all these are going to remain at least partially mysterious since consciousness is. (By the way, their deep connection to consciousness explains why these three remain philosophical problems and not the problems of some science.) And most importantly, conscious is crucially tied to your self—that inner nexus of perception and control which is you. The self is another locus of mystery. In fact, in these physicalist 127

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times, many philosophers deny that there is any such thing as the self.5 That’s how utterly strange the self and (its?) consciousness are: one can be a conscious self and yet in (apparently) good conscience deny that one is a conscious self.

Infinity and Beyond

Approximately how many infinities would you say there are? Let’s make things as simple as possible: let’s restrict our discussion of infinity to numbers, to mathematics. I know this might put some people off, but at least with numbers, matters are quite precise. It is this very precision however, that makes things here startling, perhaps even unsettling.

1, 2, 3, 4, . . . these are the counting numbers (let’s deal with 0 later). We all use them every day: to tell time, to handle money, to solve important problems in our lives. We all know that there are an infinite number of them—they go on forever (you can always add 1 to any counting number to get the next biggest number). The counting numbers are made up of even numbers (numbers cleanly divisible by 2) and odd numbers. There are an infinite number of even numbers and an infinite number of odd numbers. So we get: 2 4 6 8. . .

1 3 5 7. . . .

We can put all these sequences in alignment: 1 2 3 4 ...

2 4 6 8 ...

1 3 5 7. . . .

One can see by this alignment that for every counting number, there is an even number and the same is true for the odds. And we can see that for every even (and odd) number, there is a counting number.

We can conclude that there are exactly as many counting numbers as even numbers and odd numbers.Yet, the even numbers are a strict subset of the counting numbers, as are the odd numbers. By this, I mean that the even numbers are only a part of the counting numbers (same with the odds); yet, though the evens are only a part of the counting numbers, and though a part is always smaller than the whole, there are exactly as many of both of them. How is that possible? Well, it has to do with infinity. Ahhh . . . but which infinity?

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