I Am a Strange Loop

by Douglas R. Hofstadter

  Symbols Trigger More Symbols

  A potential new doctoral student named Nicole comes to town for a day to explore the possibility of doing a Ph.D. in my research group. After my graduate students and I have interacted with her for several hours, first at our Center and then over a Chinese dinner, we agree that we all find her mind delightfully lively and her thoughts just on our wavelength, and it’s clear that our enthusiasm is reciprocated. Needless to say, then, we are all hopeful that she’ll join us next fall. After she returns home, Nicole sends me an email saying that she is still very excited by our ideas and that they are continuing to reverberate vividly in her mind. I reply with a note of encouragement, and then there ensues an e-silence for a couple of weeks. When I finally send her a second email telling her how eager we all are for her to come next year, a couple of days pass and then a terse and somewhat starchy reply arrives, saying that she’s sorry but she’s decided to go to another university for graduate school. “But I hope we’ll have a chance to interact in the future,” she adds politely at the end.

  Well, this little episode is all fresh to me. Nicole is a unique individual, our lively conversations with her were all sui generis, and the complex configuration of symbols activated in my brain by the whole event is, by definition, unprecedented. And yet on another level that’s not true at all.

  In my many decades’ worth of episodic memory, there are precedents galore for this episode, if I just “hold it loosely in the mind”. In fact, without making the slightest effort, I find quite a few old memories bubbling up for the first time in many years, such as that time nearly thirty years ago when a very promising young candidate for our faculty seemed so interested but then, to our great surprise, he turned down our exceedingly generous offer. And that time a few years later when an extremely bright grad student of mine got all excited about accompanying me out to California for my sabbatical year but then changed his mind and soon dropped entirely out of sight, never to be heard from again. And then there’s that sad time I was terribly infatuated with that young woman from a far-off land, whose signals to me at first seemed so tinglingly filled with promise, but who then inexplicably drew back a bit, and a week or so later wound up telling me she was involved with someone else (actually, that event happened far more than just once, to my chagrin…).

  And so, one by one, all these dusty old “books” are pulled off the shelves of dormancy by the current episode, because this “unprecedented” situation, when it is perceived at an abstract level, when its crust is discarded and its core is distilled, points straight at certain other past sagas stored on the shelves of my “library”, and one after another of them gets pulled out and placed in the limelight of activation. These old sagas, long ago wrapped up in nice neat mental packages, had been idly sitting around on the shelves of my brain, waiting to be triggered if and when “the same thing” should ever happen, in new guise. And, sad to say, it did!

  When all this activity has flowed around for a while, with memories triggering memories triggering memories, something slowly settles out — some kind of “precipitate”, to borrow a term from chemistry. In this case, it finally boils down to just one word: “jilted”. Yes, I feel jilted. My research group has been jilted.

  What a phenomenal reduction in complexity! We began with an encounter that lasted for hours in two different venues and that involved many people and many thousands of words exchanged and uncountable visual impressions and then some follow-up emails, but in the end the whole thing funneled down to (or should I rather say “fizzled out in”?) just one single very disappointing six-letter word. To be sure, that’s not the only idea I retain from the saga, but “jilt” becomes one of the dominant mental categories with which Nicole’s visit will forever be associated. And of course, the Nicole saga itself gets neatly bound and stored on the shelves of my episodic memory for potential retrieval by this “I” of mine, somewhere further down the line, who knows when or where.

  The Central Loop of Cognition

  The machinery that underwrites this wonderfully fluid sort of abstract perception and memory retrieval is at least a little bit like what the skeptics above were clamoring for — it is a kind of perception of internal symbolpatterns, rather than the perception of outside events. Someone seems to be looking at configurations of activated symbols and perceiving their essence, thereby triggering the retrieval of other dormant symbols (which, as we have just seen, can be very large structures — memory packages that store entire romantic sagas, for instance), and round and round it all goes, giving rise to a lively cycle of symbolic activity — a smooth but completely improvised symbolic dance.

  The stages constituting this cycle of symbol-triggerings may at first strike you as being wildly different from the act of recognizing, say, a magnolia tree in a flood of visual input, since that involves an outside scene being processed, whereas here, by contrast, I’m looking at my own activated symbols dancing and trying to pinpoint the dance’s essence, rather than pinpointing the essence of some external scene. But I would submit that the gap is far smaller than one might at first suppose.

  My brain (and yours, too, dear reader) is constantly seeking to label, to categorize, to find precedents and analogues — in other words, to simplify while not letting essence slip away. It carries on this activity relentlessly, not only in response to freshly arriving sensory input but also in response to its own internal dance, and there really is not much of a difference between these two cases, for once sensory input has gotten beyond the retina or the tympani or the skin, it enters the realm of the internal, and from that point on, perception is solely an internal affair.

  In short, and this should please the skeptics, there is a kind of perceiver of the symbols’ activity — but what will not please them is that this “perceiver” is itself just further symbolic activity. There is not some special “consciousness locus” where something magic happens, something other than just more of the same, some locus where the dancing symbols make contact with… well, with what? What would please the skeptics? If the “consciousness locus” turned out to be just a physical part of the brain, how would that satisfy them? They would still protest that if that’s all I claim consciousness is, then it’s just insensate physical activity, no different from and no better than the mindless careening of simms in the inanimate arena of the careenium, and has nothing to do with consciousness!

  I think it may be helpful at this point to allow my various inner skeptical voices to merge into a single paper persona (hopefully not a paper tiger!), and for that persona to lock horns in an extended dialogue with another persona who essentially represents the ideas of this book. I’ll call the voice of this book “Strange Loop #641” and the voice of the skeptics “Strange Loop #642”.

  It may strike some readers that I am unfairly prejudicing the case by labeling not only myself (or rather, my proxy) a “strange loop”, but also my worthy opponent, for that might be seen as suggesting that the game is over before it’s begun. But these are nothing more than labels. What counts in the dialogue is what the characters say, not what I call them. And so, if you prefer to give Strange Loops #641 and #642 the alternative names “Inner Light #7” and “Inner Light #8”, or perhaps even “Socrates” and “Plato”, that’s fine by me.

  And now, without further ado, we tune in as our two strange loops (or inner lights) begin their amiable debate. Oops! I guess I’ve been rambling on a bit too long here, and we seem unfortunately to have missed a bit of the two friends’ opening repartee. Oh, well, that’s life. I expect you and I can jump in at this point without feeling too lost. Let’s give it a try…

  CHAPTER 20

  A Courteous Crossing of Words

  Dramatis personæ:

  Strange Loop #641: a believer in the ideas of I Am a Strange Loop

  Strange Loop #642: a doubter of the ideas of I Am a Strange Loop

  SL #642: Dreary, oh so dreary. In fact, your picture of the soul is not just dreary; it’s completely emp
ty. Vacuous. There’s nothing spiritual there at all. It’s just physical activity and nothing more.

  SL #641: What else did you expect? What else could you expect? Unless you’re a dualist, that is, and you think souls are ghostly, nonphysical things that don’t belong to the physical universe, and yet that can push pieces of it around.

  SL #642: No, I don’t go for that. It’s just that there has to be something extremely special that accounts for the existence of spiritual, mental, feeling, perceiving beings in this physical world — something that explains our inner light, our awareness, our consciousness.

  SL #641: I couldn’t agree with you more. An explanation of such elusive phenomena surely calls for something special. Building a soul out of physical nuts and bolts is a tall order. But bear in mind that in my view, consciousness is a very unusual sort of intricately organized material pattern, not just any old physical activity. It’s not the swinging of a chain, the plopping of a stone in a pond, the splashing of a waterfall, the swirling of a hurricane, the refilling of a flush toilet, the self-regulation of the temperature in a house, the flow of electrons in a program that plays chess, the wiggling of an ovum-seeking sperm, the neural firings in a hungry mosquito’s brain… but we are getting ever closer as this list progresses. An “inner light” starts to turn on as we rise in this hierarchy. The light is still incredibly dim even at the list’s end, but if we extend the list further and sweep upwards through the brains of bees, goldfish, bunnies, dogs, and toddlers, it grows far brighter. It gets very bright when we arrive at human adolescents and adults, and it stays bright for decades. What we know as our own consciousness is, yes, nothing but the physical activity inside a human brain that has lived in the world for a number of years.

  SL #642: No, the essence of consciousness is missing from your picture. You’ve described a complex set of brain activities involving symbols triggering each other, and I’m prepared to believe that something like that does take place inside brains. But that isn’t the whole story, because I am nowhere in this story. There is no room for an I. You’ve proposed myriads of unconscious particles bouncing around, or perhaps big clouds of activity made of particles — but if the universe were only that, then there would be no me, no you, no points of view. It would be the way the earth was before life evolved — millions of sunrises and sunsets, winds blowing hither and thither, clouds forming and scattering, thunderstorms swooping along valleys, boulders tumbling down mountains and gouging out gulleys, water flowing in riverbeds and carving deep canyons, waves breaking on sandy beaches, tides flowing in and out, volcanoes spewing out red-hot seas of lava, mountain chains bursting up out of plains, continents drifting and breaking apart, and so on. All very scenic, but there would be no inner life, no mind, no inner light, no I — no one to enjoy the great scenery.

  SL #641: I sympathize with your sense of the barrenness of a universe made of physical phenomena only, but some kinds of physical systems can mirror what’s on their outside and can launch actions that depend upon their perceptions. That’s the thin edge of the wedge. When perception grows sophisticated enough, it can lead to phenomena that have no counterparts in systems that perceive only in a primitive manner. By “primitive” perceiving systems, I mean entities like, for instance, thermostats, knees, sperms, and tadpoles. These are too rudimentary to merit the term “consciousness”, but when perception takes place in a system endowed with a truly rich, fluidly extensible set of symbols, then an “I” will arise just as inevitably as strange loops arise in the barren fortress of Principia Mathematica.

  SL #642: Perception?! Who’s doing the perceiving? No one! Your universe is still just a vacuous system of physical objects and their intricate, intertwined, enmeshed movements — galaxies, stars, planets, winds, rocks, water, landslides, ripples, sound waves, fire, radioactivity, and so forth. Even proteins and RNA and DNA. Even your beloved feedback loops — heat-seeking missiles, thermostats, refilling toilets, video feedback, domino chains, pool tables flooded with hordes of microscopic magnetic balls. But something crucial is missing from this bleak scene, and that’s me-ness. I am in a specific place. I’m here! What would pick out a here in a world consisting of water and float-balls in thousands of tanks, or in a world having zillions of different domino chains? There’s no here there.

  SL #641: I really do understand that this matter would nag at you; it should nag at any thinking person. My reply is this: In the vast universe of diverse physical events that you just evoked so vividly, there are certain rare spots of localized activity in which a special kind of abstractly swirling pattern can be found. Those special loci — at least the ones that we have run into so far — are human brains, and “I” ’s are restricted to those loci. Such loci are hard to find in the vast universe; they are few and far between. Wherever this special, rare kind of physical phenomenon arises, there’s an I and a here.

  SL #642: Your phrase “abstractly swirling pattern” makes me think of a physical vortex, like a hurricane or a whirlpool or a spiral galaxy — but I suppose those aren’t abstract enough for you.

  SL #642: No, they really aren’t. Whirlpools and hurricanes are merely spinning vortices — fluid cousins to tops and gyroscopes. To make an “I” you need meanings, and to make meanings you need perception and categories — in fact, a repertoire of categories that keeps on building on itself, growing and growing and growing. Such things are nowhere to be found in the physical vortices you mentioned. That’s why a far better metaphor for an “I” is the structure of the self-referring formulas that Gödel found in the barren-seeming universe of PM. His formulas, like human “I” ’s, are extremely intricately and delicately structured, and are hardly a dime a dozen. “Ordinary” formulas of PM, like “0+0=0”, say, or a formula that states that every integer is the sum of at most four squares, are the analogues to inert, “I”-less physical objects, like grains of sand or bowling balls. Those simple kinds of formulas don’t have wraparound high-level meanings in the way that Gödel’s special strings do. It takes a great deal of number-theoretical machinery to build up from ordinary assertions about numbers to the complexity of Gödelian strange loops, and likewise it takes a great deal of evolution to build up from very simple feedback loops to the complexity of strange loops in brains.

  SL #642: Suppose I granted you that there are lots of abstract “strange loops” floating around the universe, which somehow coalesced over the course of billions of years of evolution — strange loops residing in crania, a bit like audio feedback loops residing in auditoriums. They can be as complex as you like; the complexity of their physical activity doesn’t matter one whit to me. The knotty issue that simply will not go away is: What would make one of those strange loops me? Which one? You can’t answer that.

  SL #641: I can, although you won’t like my answer. What makes one of them you is that it is resident in a particular brain that went through all the experiences that made you you.

  SL #642: That’s just a tautology!

  SL #641: Not really. It’s a subtle idea whose crux is that what you call “I” is an outcome, not a starting point. You coalesced in an unplanned fashion, coming only slowly into existence, not in a flash. At the beginning, when the brain that would later house your soul was taking form, there was no you. But that brain slowly grew, and its experiences slowly accumulated. Somewhere along the way, as more and more things happened to it, were registered by it, and became internalized in it, it started imitating the cultural and linguistic conventions in which it was immersed, and thus it tentatively said “I” about itself (even though the referent of that word was still very blurry). That’s roughly when it noticed it was somewhere — and not surprisingly, it was where a certain brain was! At that point, though, it didn’t know anything about its brain. What it knew instead was its brain’s container, which was a certain body. But even though it didn’t know anything about its brain, that nascent “I” faithfully followed its brain around just as a shadow always tags along after a moving object.
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  SL #642: You’re not dealing with my question, which is about how to pick me out in a world of indistinguishable physical structures.

  SL #641: All right, let me turn straight to that. To you, all the brains housing strange loops seem no different from thousands of sewing machines scattered hither and yon, all clicking away. You would ask, “Which sewing machine is me?” Well, of course, none of them is you — and that’s because none of them perceives anything. You see brains that house strange loops as being just as inert and identity-lacking as sewing machines, pinwheels, or merry-go-rounds. But the funny thing is that the beings whose brains house those strange loops don’t agree with you that they have no identity. One of them insists, “I’m the one right here, looking at this purple flower, not the one over there, drinking a milkshake!” Another one insists, “I’m the one drinking this chocolate shake, not the one looking at that flower!” Each one of them is convinced of being somewhere and of seeing things and hearing things and having experiences. What makes you reject their claims?

  SL #642: I don’t reject their claims. Those claims are perfectly valid — it’s just that their validity has nothing to do with brains housing strange loops. You’re focusing on the wrong thing. Any claims of “being here” and “being conscious” are valid because there is something extra, something over and above strange loops, that makes a brain be the locus of a soul. I can’t tell you just what it is, but I know this is true, because I am not just physical stuff happening somewhere in the universe. I experience things, such as that purple flower in the garden and that loud motorcycle a couple of blocks away. And my experience is the primary data on which everything else that I say is based, so you cannot deny my claim.

  SL #641: How is that any different from what I’ve described? A sufficiently complex brain not only can perceive and categorize but it can verbalize what it has categorized. Like you, it can talk about flowers and gardens and motorcycle roars, and it can talk about itself, saying where it is and where it is not, it can describe its present and past experiences and its goals and beliefs and confusions… What more could you want? Why is that not what you call “experience”?