Well then, how about more basic things like “in pain” and “not in pain”? I am still skeptical. On the other hand, I can easily imagine signals sent from a mosquito’s eye to its brain and causing other signals to bounce back to its wings, amounting to a reflex verbalizable to us humans as “Flee threat on left” or simply “Outta here!” — but putting it into telegraphic English words in this fashion
still
makes the mosquito sound too aware, I am afraid. I would be quite happy to compare a mosquito’s inner life to that of a flush toilet or a thermostat, but that’s about as far as I personally would go. Mosquito behavior strikes me as perfectly comprehensible without recourse to anything that deserves the name “symbol”. In other words, a mosquito’s wordless and conceptless danger-fleeing behavior may be less like perception as we humans know it, and more like the wordless and conceptless hammer-fleeing behavior of your knee when the doctor’s hammer hits it and you reflexively kick. Does a mosquito have more of an inner life than your knee does?
Does a mosquito have even the tiniest glimmering of itself as being a moving part in a vast world? Once again, I suspect not, because this would require all sorts of abstract symbols to reside in its microscopic brain — symbols for such notions as “big”, “small”, “part”, “place”, “move”, and so on, not to mention “myself ”. Why would a mosquito need such luxuries? How would they help it find blood or a mate more efficiently? A hypothetical mosquito that had enough brainpower to house fancy symbols like these would be an egghead with a lot more neurons to carry around than its more streamlined and simpleminded cousins, and it would thereby be heavier and slower than they are, meaning that it wouldn’t be able to compete with them in the quests for blood and reproduction, and so it would lose out in the evolutionary race.
My intuition, at any rate, is that a mosquito’s very efficient teeny little nervous system lacks perceptual categories (and hence symbols) altogether. If I am not mistaken, this reduces the kind of self-perception loops that can exist in a mosquito’s brain to an exceedingly low level, thus rendering a mosquito a very “small-souled man” indeed. I hope it doesn’t sound too blasphemous or crazy if I suggest that a mosquito’s “soul” might be roughly the same “size” as that of the little red spot of light that bounces around on the wall at the Exploratorium — let’s say, one ten-billionth of one huneker (
i.e..,
roughly one trillionth of a human soul).
To be sure, I’m being flippant in making this numerical estimate, but I am quite serious in presenting my subjective guess about whether symbols are present or absent in a mosquito’s brain. Nevertheless, it is just a subjective guess, and you may not agree with it, but disputes about such fine points are not germane here. The key point is much simpler and cruder: merely that there is
some
kind of creature to which essentially this level of complexity, and no greater level, would apply. If you disagree with my judgment, then I invite you to slide up or down the scale of various animal intellects until you feel you have hit the appropriate level.
One last reflection on all this. Some readers might protest, with what sounds like great sincerity, about all these questions about a mosquito’s-eye view on the world: “How could we ever know? You and I can’t get inside a mosquito’s brain or mind — no one can. For all I know, mosquitoes are every bit as conscious as I am!” Well, I would respectfully suggest that such claims cannot be sincere, because here’s ten bucks that say such readers would swat a mosquito perched on their arm without giving it a second thought. Now if they truly believe that mosquitoes are quite possibly every bit as sentient as themselves, then how come they’re willing to snuff mosquito lives in an instant? Are these people not vile monsters if they are untroubled by executing living creatures who, they claim, may well enjoy just as much consciousness as do humans? I think you have to judge people’s opinions not by their words, but by their deeds.
An Interlude on Robot Vehicles
Before moving on to consider higher animal species, I wish to insert a brief discussion of cars that drive themselves down smooth highways or across rocky deserts. Aboard any such vehicle are one or more television cameras (and laser rangefinders and other kinds of sensors) equipped with extra processors that allow the vehicle to make sense of its environment. No amount of simplistic analysis of just the colors or the raw shapes on the screen is going to provide good advice as to how to get around obstacles without toppling or getting stuck. Such a system, in order to drive itself successfully, has to have a nontrivial storehouse of prepackaged knowledge structures that can be selectively triggered by the scene outside. Thus, some knowledge of such abstractions as “road”, “hill”, “gulley”, “mud”, “rock”, “tree”, “sand”, and many others will be needed if the vehicle is going to avoid getting stuck in mud, trapped in a gulley, or wedged between two boulders. The television cameras and the rangefinders (etc.) provide only the simplest
initial
stages of the vehicle’s “perceptual process”, and the triggering of various knowledge structures of the sort that were just mentioned corresponds to the far end, the
symbolic
end, of the process.
I slightly hesitated about putting quotation marks around the words “perceptual process” in the previous sentence, but I made an arbitrary choice, figuring that I was damned if I did and damned if I didn’t. That is, if I left them off, I would be implicitly suggesting that what is going on in such a robot vehicle’s processing of its visual input is truly like our own perception, whereas if I put them on, I would be implicitly suggesting that there is some kind of unbridgeable gulf between what “mere machines” can do and what living creatures do. Either choice is too black-and-white a position. Quotation marks, regrettably, don’t come in shades of gray; if they did, I would have used some intermediate shade to suggest a more nuanced position.
The self-navigation of today’s robot vehicles, though very impressive, is still a far cry from the level of mammalian perception, and yet I think it is fair to say that such a vehicle’s “perception” (sorry for the unshaded quotation marks!) of its environment is just as sophisticated as a mosquito’s “perception” (there — I hope to have somewhat evened the score), and perhaps considerably more so. (A beautiful treatment of this concept of robot vehicles and what different levels of “perception” will buy them is given by Valentino Braitenberg in his book
Vehicles.
)
Without going into more detail, let me simply say that it makes perfect sense to discuss living animals and self-guiding robots in the same part of this book, for today’s technological achievements are bringing us ever closer to understanding what goes on in living systems that survive in complex environments. Such successes give the lie to the tired dogma endlessly repeated by John Searle that computers are forever doomed to mere “simulation” of the processes of life. If an automaton can drive itself a distance of two hundred miles across a tremendously forbidding desert terrain, how can this feat be called merely a “simulation”? It is certainly as genuine an act of survival in a hostile environment as that of a mosquito flying about a room and avoiding being swatted.
Pondering Dogthink
Let us return to our climb up the purely biological ladder of perceptual sophistication, rising from viruses to bacteria to mosquitoes to frogs to dogs to people (I’ve skipped a few rungs in there, I know). As we move higher and higher, the repertoire of triggerable symbols of course becomes richer and richer — indeed, what else could “climbing up the ladder” mean? Simply judging from their behavior, no one could doubt that pet dogs develop a respectable repertoire of categories, including such examples as “my paw”, “my tail”, “my food”, “my water”, “my dish”, “indoors”, “outdoors”, “dog door”, “human door”, “open”, “closed”, “hot”, “cold”, “nighttime”, “daytime”, “sidewalk”, “road”, “bush”, “grass”, “leash”, “take a walk”, “the park”, “car”, “car door”, “my big owner”, “my little owner”, “the cat”, “the friendly neighbor dog”, “the mean neighbor dog”, “UPS truck”, “the vet”, “ball”, “eat”, “lick”, “drink”, “play”, “sit”, “sofa”, “climb onto”, “bad behavior”, “punishment”, and on and on. Guide dogs often learn a hundred or more words and respond to highly variegated instances of these concepts in many different contexts, thus demonstrating something of the richness of their internal category systems (
i.e.,
their repertoires of triggerable symbols).
I used a set of English words and phrases in order to suggest the nature of a canine repertoire of categories, but of course I am not claiming that human words are involved when a dog reacts to a neighbor dog or to the UPS truck. But one word bears special mention, and that is the word “my”, as in “my tail” or “my dish”. I suspect most readers would agree that a pet dog realizes that a particular paw belongs to itself, as opposed to being merely a random physical object in the environment or a part of some other animal. Likewise, when a dog chases its tail, even though it is surely unaware of the loopy irony of the act, it must know that
that
tail is part of its
own
body. I am thus suggesting that a dog has some kind of rudimentary self-model, some kind of sense of itself. In addition to its symbols for “car”, “ball”, and “leash”, and its symbols for other animals and human beings, it has some kind of internal cerebral structure that represents itself (
i.e.,
the dog itself, not the symbol itself!).
If you doubt dogs have this, then what about chimpanzees? What about two-year-old humans? In any case, the emergence of this kind of reflexive symbolic structure, at whatever level of sentience it first enters the picture, constitutes the central germ, the initial spark, of “I”-ness, the tiny core to which more complex senses of “I”-ness will then accrete over a lifetime, like the snowflake that grows around a tiny initial speck of dust.
Given that most grown dogs have a symbol for
dog,
does a dog know, in some sense or other, that it, too, belongs to the category
dog
? When it looks at a mirror and sees its master standing next to “some dog”, does it realize that that dog is itself? These are interesting questions, but I will not attempt to answer them. I suspect that this kind of realization lies near the fringes of canine mental ability, but for my purposes in this essay, it doesn’t really matter on which side dogs fall. After all, this book is not about dogs. The key point here is that there is
some
level of complexity at which a creature starts applying some of its categories to itself, starts building mental structures that represent itself, starts placing itself in some kind of “intellectual perspective” in relationship to the rest of the world. In this respect, I think dogs are hugely more advanced than mosquitoes, and I suspect you agree.
On the other hand, I suspect that you also agree with me that a dog’s soul is considerably “smaller” than a human one — otherwise, why wouldn’t we both be out vehemently demonstrating at our respective animal shelters against the daily putting to “sleep” of stray hounds and helpless puppies? Would you condone the execution of homeless people and abandoned babies? What makes you draw a distinction between dogs and humans? Could it be the relative sizes of their souls? How many hunekers would dogs have to have, on the average, for you to decide to organize a protest demonstration at an animal shelter?
Creatures at the sophistication level of dogs, thanks to the inevitable flipping-around of their perceptual apparatus and their modest but nontrivial repertoire of categories, cannot help developing an approximate sense of themselves as physical entities in a larger world. (Robot vehicles in desert-crossing contests don’t spend their precious time looking at themselves — it would be as useless as spinning their wheels — so their sense of self is considerably less sophisticated than that of a dog.) Although a dog will never know a thing about its kidneys or its cerebral cortex, it will develop some notion of its paws, mouth, and tail, and perhaps of its tongue or its teeth. It may have seen itself in a mirror and perhaps realized that “that dog over there by my master” is in fact itself. Or it may have seen itself in a home video with its master, recognized the recording of its master’s voice, and realized that the barking on the video was its own.
And yet all of this, though in many ways impressive, is still extremely limited in comparison to the sense of self and “I”-ness that continually grows over the course of a normal human being’s lifetime. Why is this the case? What’s missing in Fido, Rover, Spot, Blackie, and Old Dog Tray?
The Radically Different Conceptual Repertoire of Human Beings
A spectacular evolutionary gulf opened up at some point as human beings were gradually separating from other primates: their category systems became
arbitrarily extensible.
Into our mental lives there entered a dramatic quality of open-endedness, an essentially unlimited extensibility, as compared with a very palpable limitedness in other species.
Concepts in the brains of humans acquired the property that they could get rolled together with other concepts into larger packets, and any such larger packet could then become a new concept in its own right. In other words, concepts could
nest
inside each other hierarchically, and such nesting could go on to arbitrary degrees. This reminds me — and I do not think it is a pure coincidence — of the huge difference, in video feedback, between an infinite corridor and a truncated one.
For instance, the phenomenon of having offspring gave rise to concepts such as “mother”, “father”, and “child”. These concepts gave rise to the nested concept of “parent” — nested because forming it depends upon having three prior concepts: “mother”, “father”, and the abstract idea of “either/or”. (Do dogs have the concept “either/or”? Do mosquitoes?) Once the concept of “parent” existed, that opened the door to the concepts of “grandmother” (“mother of a parent”) and “grandchild” (“child of a child”), and then of “great-grandmother” and “great-grandchild”. All of these concepts came to us courtesy of nesting. With the addition of “sister” and “brother”, then further notions having greater levels of nesting, such as “uncle”, “aunt”, and “cousin”, could come into being. And then a yet more nested notion such as “family” could arise. (“Family” is more nested because it takes for granted and builds on all these prior concepts.)