O what a world of unseen visions and heard silences, this insubstantial country of the mind! What ineffable essences, these touchless rememberings and unshowable reveries! And the privacy of it all! A secret theater of speechless monologue and prevenient counsel, an invisible mansion of all moods, musings, and mysteries, an infinite resort of disappointments and discoveries. A whole kingdom where each of us reigns reclusively alone, questioning what we will, commanding what we can. A hidden hermitage where we may study out the troubled book of what we have done and yet may do. An introcosm that is more myself than anything I can find in a mirror. This consciousness that is myself of selves, that is everything, and yet nothing at all ? what is it?
And where did it come from?
Few questions have endured longer or traversed a more perplexing history than this, the problem of consciousness and its place in nature. Despite centuries of pondering and experiment, of trying to get together two supposed entities called mind and matter in one age, subject and object in another, or soul and body in still others, despite endless discoursing on the streams, states, or contents of consciousness, of distinguishing terms like intuitions, sense data, the given, raw feels, the sensa, presentations and representations, the sensations, images, and affections of structuralist introspections, the evidential data of the scientific positivist, phenomenological fields, the apparitions of Hobbes, the phenomena of Kant, the appearances of the idealist, the elements of Mach, the phanera of Peirce, or the category errors of Ryle, inspite of all of these, the problem of consciousness is still with us.
Something about it keeps returning, not taking a solution. It is the difference that will not go away, the difference between what others see of us and our sense of our inner selves and the deep feelings that sustain it. The difference between the you-and-me of the shared behavioral world and the unlocatable location of things thought about. Our reflections and dreams, and the imaginary conversations we have with others, in which never-to- be-known-by-anyone we excuse, defend, proclaim our hopes and regrets, our futures and our pasts, all this thick fabric of fancy is so absolutely different from handable, standable, kickable reality with its trees, grass, tables, oceans, hands, stars ? even brains! How is this possible? How do these ephemeral existences of our lonely experience fit into the ordered array of nature that somehow surrounds and engulfs this core of knowing?
Men have been conscious of the problem of consciousness almost since consciousness began. And each age has described consciousness in terms of its own theme and concerns. In the golden age of Greece, when men traveled about in freedom while slaves did the work, consciousness was as free as that. Heraclitus, in particular, called it an enormous space whose boundaries, even by traveling along every path, could never be found out.1 A millennium later, Augustine among the caverned hills of Carthage was astonished at the “mountains and hills of my high imaginations,” “the plains and caves and caverns of my memory” with its recesses of “manifold and spacious chambers, wonderfully furnished with unnumberable stores.” 2. Note how the metaphors of mind are the world it perceives.
The first half of the nineteenth century was the age of the great geological discoveries in which the record of the past was written in layers of the earth’s crust. And this led to the popularization of the idea of consciousness as being in layers which recorded the past of the individual, there being deeper and deeper layers until the record could no longer be read. This emphasis on the unconscious grew until by 1875 most psychologists were insisting that consciousness was but a small part of mental life, and that unconscious sensations, unconscious ideas, and unconscious judgments made up the majority of mental processes.3 In the middle of the nineteenth century chemistry succeeded geology as the fashionable science, and consciousness from James Mill to Wundt and his students, such as Titchener, was the compound structure that could be analyzed in the laboratory into precise elements of sensations and feelings. And as steam locomotives chugged their way into the pattern of everyday life toward the end of the nineteenth century, so they too worked their way into the consciousness of consciousness, the subconscious becoming a boiler of straining energy which demanded manifest outlets and when repressed pushed up and out into neurotic behavior and the spinning camouflaged fulfillments of going-nowhere dreams. There is not much we can do about such metaphors except to state that that is precisely what they are.
Now originally, this search into the nature of consciousness was known as the mind-body problem, heavy with its ponderous philosophical solutions. But since the theory of evolution, it has bared itself into a more scientific question. It has become the problem of the origin of mind, or, more specifically, the origin of consciousness in evolution. Where can this subjective experience which we introspect upon, this constant companion of hosts of associations, hopes, fears, affections, knowledges, colors, smells, toothaches, thrills, tickles, pleasures, distresses, and desires ? where and how in evolution could all this wonderful tapestry of inner experience have evolved? How can we derive this inwardness out of mere matter? And if so, when?
This problem has been at the very center of the thinking of the twentieth century. And it will be worthwhile here to briefly look at some of the solutions that have been proposed. I shall mention the eight that I think are most important.
Consciousness as a Property of Matter
The most extensive possible solution is attractive mostly to physicists. It states that the succession of subjective states that we feel in introspection has a continuity that stretches all the way back through phylogenetic evolution and beyond into a fundamental property of interacting matter. The relationship of consciousness to what we are conscious of is not fundamentally different from the relationship of a tree to the ground in which it is rooted, or even of the gravitational relationship between two celestial bodies. This view was conspicuous in the first quarter of this century. What Alexander called compresence or Whitehead called prehension provided the groundwork of a monism that moved on into a flourishing school called Neo-Realism. If a piece of chalk is dropped on the lecture table, that interaction of chalk and table is different only in complexity from the perceptions and knowledges that fill our minds. The chalk knows the table just as the table knows the chalk. That is why the chalk stops at the table.
This is something of a caricature of a very subtly worked out position, but it nevertheless reveals that this difficult theory is answering quite the wrong question. We are not trying to explain how we interact with our environment, but rather the particular experience that we have in introspecting. The attractiveness of this kind of neo-realism was really a part of an historical epoch when the astonishing successes of particle physics were being talked of everywhere. The solidity of matter was being dissolved into mere mathematical relationships in space, and this seemed like the same unphysical quality as the relationship of individuals conscious of each other.
Consciousness as a Property of Protoplasm
The next most extensive solution asserts that consciousness is not in matter per se; rather it is the fundamental property of all living things. It is the very irritability of the smallest one-celled animals that has had a continuous and glorious evolution up through coelenterates, the protochordates, fish, amphibians, reptiles, and mammals to man. A wide variety of nineteenth- and twentieth-century scientists, including Charles Darwin and E. B. Titchener, found this thesis unquestionable, initiating in the first part of this century a great deal of excellent observation of lower organisms. The search for rudimentary consciousnesses was on. Books with titles such as The Animal Mind or The Psychic Life of Micro-Organisms were eagerly written and eagerly read.4 And anyone who observes amoebas hunting food or responding to various stimuli, or paramecia avoiding obstacles or conjugating, will know the almost passionate temptation to apply human categories to such behavior.
And this brings us to a very important part of the problem ? our sympathy and identification with other living things. Whatever conclusions we may hold on the matter, it is certainly a part of our consciousness to ‘see’ into the consciousness of others, to identify with our friends and families so as to imagine what they are thinking and feeling. And so if animals are behaving such as we would in similar situations, so well are we trained in our human sympathies that it requires a particular vigor of mind to suppress such identifications when they are not warranted. The explanation for our imputing consciousness to protozoa is simply that we make this common and misleading identification. Yet the explanation for their behavior resides entirely in physical chemistry, not in introspective psychology.
Even in animals with synaptic nervous systems, the tendency to read consciousness into their behavior comes more from ourselves than from our observations. Most people will identify with a struggling worm. But as every boy who has baited a fish hook knows, if a worm is cut in two, the front half with its primitive brain seems not to mind as much as the back half, which writhes in ‘agony’.5 But surely if the worm felt pain as we do, surely it would be the part with the brain that would do the agonizing. The agony of the tail end is our agony, not the worm’s; its writhing is a mechanical release phenomenon, the motor nerves in the tail end firing in volleys at being disconnected from their normal inhibition by the cephalic ganglion.
Consciousness as Learning
To make consciousness coextensive with protoplasm leads, of course, to a discussion of the criterion by which consciousness can be inferred. And hence a third solution, which states that consciousness began not with matter, nor at the beginning of animal life, but at some specific time after life had evolved. It seemed obvious to almost all the active investigators of the subject that the criterion of when and where in evolution consciousness began was the appearance of associative memory or learning. If an animal could modify its behavior on the basis of its experience, it must be having an experience; it must be conscious. Thus, if one wished to study the evolution of consciousness, one simply studied the evolution of learning. This was indeed how I began my search for the origin of consciousness. My first experimental work was a youthful attempt to produce signal learning (or a conditional response) in an especially long suffering mimosa plant. The signal was an intense light; the response was the drooping of a leaf to a carefully calibrated tactile stimulus where it joined the stem. After over a thousand pairings of the light and the tactile stimulus, my patient plant was as green as ever. It was not conscious. That expected failure behind me, I moved on to protozoa, delicately running individual paramecia in a T-maze engraved in wax on black Bakelite, using direct current shock to punish the animal and spin it around if it went to the incorrect side. If paramecia could learn, I felt they had to be conscious. Moreover I was extremely interested in what would happen to the learning (and the consciousness) when the animal divided. A first suggestion of positive results was not borne out in later replications. After other failures to find learning in the lower phyla, I moved on to species with synaptic nervous systems, flatworms, earthworms, fish, and reptiles, which could indeed learn, all on the naive assumption that I was chronicling the grand evolution ofconsciousness.6
Ridiculous! It was, I fear, several years before I realized that this assumption makes no sense at all. When we introspect, it is not upon any bundle of learning processes, and particularly not the types of learning denoted by conditioning and T-mazes. Why then did so many worthies in the lists of science equate consciousness and learning? And why had I been so lame of mind as to follow them?
The reason was the presence of a kind of huge historical neurosis. Psychology has many of them. And one of the reasons that the history of science is essential to the study of psychology is that it is the only way to get out of and above such intellectual disorders. The school of psychology known as Associationism in the eighteenth and nineteenth centuries had been so attractively presented and so peopled with prestigious champions that its basic error had become imbedded in common thought and language. That error was, and still is, that consciousness is an actual space inhabited by elements called sensations and ideas, and the association of these elements because they are like each other, or because they have been made by the external world to occur together, is indeed what learning is and what the mind is all about. So learning and consciousness are confused and muddled up with that vaguest of terms, experience. It is this confusion that lingered unseen behind my first struggles with the problem, as well as the huge emphasis on animal learning in the first half of the twentieth century. But it is now absolutely clear that in evolution the origin of learning and the origin of consciousness are two utterly separate problems. We shall be demonstrating this assertion with more evidence in the next chapter.
Consciousness as a Metaphysical Imposition
All the theories I have so far mentioned begin in the assumption that consciousness evolved biologically by simple natural selection. But another position denies that such an assumption is even possible. Is this consciousness, it asks, this enormous influence of ideas, principles, beliefs over our lives and actions, really derivable from animal behavior? Alone of species, all alone! we try to understand ourselves and the world. We become rebels or patriots or martyrs on the basis of ideas. We build Chartres and computers, write poems and tensor equations, play chess and quartets, sail ships to other planets and listen in to other galaxies ? what have these to do with rats in mazes or the threat displays of baboons? The continuity hypothesis of Darwin for the evolution of mind is a very suspicious totem of evolutionary mythology.7 The yearning for certainty which grails the scientist, the aching beauty which harasses the artist, the sweet thorn of justice which fierces the rebel from the eases of life, or the thrill of exultation with which we hear of true acts of that now difficult virtue of courage, of cheerful endurance of hopeless suffering ? are these really derivable from matter? Or even continuous with the idiot hierarchies of speechless apes? The chasm is awesome. The emotional lives of men and of other mammals are indeed marvelously similar. But to focus upon the similarity unduly is to forget that such a chasm exists at all. The intellectual life of man, his culture and history and religion and science, is different from anything else we know of in the universe. That is fact. It is as if all life evolved to a certain point, and then in ourselves turned at a right angle and simply exploded in a different direction.
The appreciation of this discontinuity between the apes and speaking civilized ethical intellectual men has led many scientists back to a metaphysical view. The interiority of consciousness just could not in any sense be evolved by natural selection out of mere assemblages of molecules and cells. There has to be more to human evolution than mere matter, chance, and survival. Something must be added from outside of this closed system to account for something so different as consciousness. Such thinking began with the beginning of modern evolutionary theory, particularly in the work of Alfred Russel Wallace, the codiscoverer of the theory of natural selection. Following their twin announcements of the theory in 1858, both Darwin and Wallace struggled like Laocoons with the serpentine problem of human evolution and its encoiling difficulty of consciousness. But where Darwin clouded the problem with his own naivete, seeing only continuity in evolution, Wallace could not do so. The discontinuities were terrifying and absolute. Man’s conscious faculties, particularly, “could not possibly have been developed by means of the same laws which have determined the progressive development of the organic world in general, and also of man’s physical organism.”8 He felt the evidence showed that some metaphysical force had directed evolution at three different points: the beginning of life, the beginning of consciousness, and the beginning of civilized culture. Indeed, it is partly because Wallace insisted on spending the latter part of his life searching in vain among the seances of spiritualists for evidence of such metaphysical imposition that his name is not as well known as is Darwin’s as the discoverer of evolution by natural selection. Such endeavors were not acceptable to the scientific Establishment. To explain consciousness by metaphysical imposition seemed to be stepping outside the rules of natural science. And that indeed was the problem, how to explain consciousness in terms of natural science alone.
The Helpless Spectator Theory
In reaction to such metaphysical speculations, there grew up through this early period of evolutionary thinking an increasingly materialist view. It was a position more consistent with straight natural selection. It even had inherent in it that acrid pessimism that is sometimes curiously associated with really hard science. This doctrine assures us consciousness does nothing at all, and in fact can do nothing. Many tough-minded experimentalists still agree with Herbert Spencer that such a downgrading of consciousness is the only view that is consistent with straight evolutionary theory. Animals are evolved; nervous systems and their mechanical reflexes increase in complexity; when some unspecified degree of nervous complexity is reached, consciousness appears, and so begins its futile course as a helpless spectator of cosmic events.
What we do is completely controlled by the wiring diagram of the brain and its reflexes to external stimuli. Consciousness is not more than the Heat given off by the wires, a mere epiphenomenon. Conscious feelings, as Hodgson put it, are mere colors laid on the surface of a mosaic which is held together by its stones, not by the colors.9 Or as Huxley insisted in a famous essay, “we are conscious automata.”10 Consciousness can no more modify the working mechanism of the body or its behavior than can the whistle of a train modify its machinery or where it goes. Moan as it will, the tracks have long ago decided where the train will go. Consciousness is the melody that floats from the harp and cannot pluck its strings, the foam struck raging from the river that cannot change its course, the shadow that loyally walks step for step beside the pedestrian, but is quite unable to influence his journey.
It is William James who has given the best discussion of the conscious automaton theory.11 His argument here is a little like Samuel Johnson’s downing philosophical idealism by kicking a stone and crying, “I refute it thus!” It is just plain inconceivable that consciousness should have nothing to do with a business which it so faithfully attends. If consciousness is the mere impotent shadow of action, why is it more intense when action is most hesitant? And why are we least conscious when doing something most habitual? Certainly this seesawing relationship between consciousness and actions is something that any theory of consciousness must explain.
The doctrine of emergent evolution was very specifically welcomed into court to rescue consciousness from this undignified position as a mere helpless spectator. It was also designed to explain scientifically the observed evolutionary discontinuities that had been the heart of the metaphysical imposition argument. And when I first began to study it some time ago, I, too, felt with a shimmering flash how everything, the problem of consciousness and all, seemed to shiveringly fall into accurate and wonderful place.
Its main idea is a metaphor: Just as the property of wetness cannot be derived from the properties of hydrogen and oxygen alone, so consciousness emerged at some point in evolution in away underivable from its constituent parts.
While this simple idea goes back to John Stuart Mill and G. H. Lewes, it was Lloyd Morgan’s version in his Emergent Evolution of 1923 that really captured the cheering. This book is a thoroughgoing scheme of emergent evolution vigorously carried all the way back into the physical realm. All the properties of matter have emerged from some unspecified forerunner. Those of complex chemical compounds have emerged from the conjunction of simpler chemical components. Properties distinctive of living things have emerged from the conjunctions of these complex molecules. And consciousness emerged from living things. New conjunctions bring about new kinds of relatedness which bring about new emergents. So the new emergent properties are in each case effectively related to the systems from which they emerge. In fact, the new relations emergent at each higher level guide and sustain the course of events distinctive of that level. Consciousness, then, emerges as something genuinely new at a critical stage of evolutionary advance. When it has emerged, it guides the course of events in the brain and has causal efficacy in bodily behavior.
The whoop with which this antireductionist doctrine was greeted by the majority of prominent biological and comparative psychologists, frustrated dualists all, was quite undignified. Biologists called it a new Declaration of Independence from physics and chemistry. “No longer can the biologist be bullied into suppressing observed results because they are not discovered nor expected from work on the non-living. Biology becomes a science in its own right. Prominent neurologists agreed that now we no longer had to think of consciousness as merely dancing an as insiduous but futile attendance upon our brain processes.12 The origin of consciousness seemed to have been pointed at in such away as to restore consciousness to its usurped throne as the governor of behavior and even to promise new and unpredictable emergents in the future. But had it? If consciousness emerged in evolution, when? In what species? What kind of a nervous system is necessary? Andas the first flush of a theoretical breakthrough waned, it was seen that nothing about the problem had really changed. It is these specifics that need to be answered. What is wrong about emergent evolution is not the doctrine, but the release back into old comfortable ways of thinking about consciousness and behavior, the license that it gives to broad and vacuous generalities. Historically, it is of interest here to note that all this dancing in the aisles of biology over emergent evolution was going on at the same time that a stronger, less-educated doctrine with a rigorous experimental campaign was beginning its robust conquest of psychology. Certainly one way of solving the problem of consciousness and its place in nature is to deny that consciousness exists at all.
It is an interesting exercise to sit down and try to be conscious of what it means to say that consciousness does not exist. History has not recorded whether or not this feat was attempted by the early behaviorists. But it has recorded everywhere and in large the enormous influence which the doctrine that consciousness does not exist has had on psychology in this century. And this is behaviorism. Its roots rummage far back into the musty history of thought, to the so-called Epicureans of the eighteenth century and before, to attempts to generalize tropisms from plants to animals to man, to movements called Objectivism, or more particularly, Actionism. For it was Knight Dunlap’s attempt to teach the latter to an excellent but aweless animal psychologist, John B. Watson, that resulted in a new word, Behaviorism.13 At first, it was very similar to the helpless spectator theory we have already examined. Consciousness just was not important in animals. But after a World War and a little invigorating opposition, behaviorism charged out into the intellectual arena with the snorting assertion that consciousness is nothing at all.
What a startling doctrine! But the really surprising thing is that, starting off almost as a flying whim, it grew into a movement that occupied center stage in psychology from about 1920 to 1960. The external reasons for the sustained triumph of such a peculiar position are both fascinating and complex. Psychology at the time was trying to wriggle out of philosophy into a separate academic discipline and used behaviorism to do so. The immediate adversary of behaviorism, Titchenerian introspectionism, was a pale and effete opponent, based as it was on a false analogy between consciousness and chemistry. The toppled idealism after World War I created a revolutionary age demanding new philosophies. The intriguing successes of physics and general technology presented both a model and a means that seemed more compatible with behaviorism. The world was weary and wary of subjective thought and longed for objective fact. And in America objective fact was pragmatic fact. Behaviorism provided this in psychology. It allowed a new generation to sweep aside with one impatient gesture all the worn-out complexities of the problem of consciousness and its origin. We would turn over a new leaf. We would make a fresh start. And the fresh start was a success in one laboratory after another. But the single inherent reason for its success was not its truth, but its program. And what a truly vigorous and exciting program of research it was! with its gleaming stainless-steel promise of reducing all conduct to a handful of reflexes and conditional responses developed from them, of generalizing the spinal reflex terminology of stimulus and response and reinforcement to the puzzles of headed behavior and so seeming to solve them, of running rats through miles and miles of mazes into more fascinating mazes of objective theorems, and its pledge, its solemn pledge to reduce thought to muscle twitches and personality to the woes of Little Albert.14 In all this there was a heady excitement that is difficult to relate at this remove. Complexity would be made simple, darkness would be made light, and philosophy would be a thing of the past.
From the outside, this revolt against consciousness seemed to storm the ancient citadels of human thought and set its arrogant banners up in one university after another. But having once been a part of its major school, I confess it was not really what it seemed. Off the printed page, behaviorism was only a refusal to talk about consciousness. Nobody really believed he was not conscious. And there was a very real hypocrisy abroad, as those interested in its problems were forcibly excluded from academic psychology, as text after text tried to smother the unwanted problem from student view. In essence, behaviorism was a method, not the theory that it tried to be. And as a method, it exorcised old ghosts. It gave psychology a thorough house cleaning. And now the closets have been swept out and the cupboards washed and aired, and we are ready to examine the problem again.
Consciousness as the Reticular Activating System
But before doing so, one final approach, a wholly different approach, and one that has occupied me most recently, the nervous system. How often in our frustrations with trying to solve the mysteries of mind do we comfort our questions with anatomy, real or fancied, and think of a thought as a particular neuron or a mood as a particular neurotransmitter! It is a temptation born of exasperation with the untestableness and vagueness of all the above solutions. Away with these verbal subtleties! These esoteric poses of philosophy and even the paper theories of behaviorists are mere subterfuges to avoid the very material we are talking about! Here we have an animal ? make him a man if you will ? here he is on the table of our analysis. If he is conscious, it has to be here, right here in him, in the brain in front of us, not in the presumptuous inklings of philosophy back in the incapable past! And today we at last have the techniques to explore the nervous system directly, brain to brain. Somewhere here in a mere three-and-a-half pound lump of pinkish-gray matter, the answer has to be. All we have to do is to find those parts of the brain that are responsible for consciousness, then trace out their anatomical evolution, and we will solve the problem of the origin of consciousness. Moreover, if we study the behavior of present-day species corresponding to various stages in the development of these neurological structures, we will be able at last to reveal with experimental exactness just what consciousness basically is.
Now this sounds like an excellent scientific program. Ever since Descartes chose the brain’s pineal body as the seat of consciousness and was roundly refuted by the physiologists of his day, there has been a fervent if often superficial search for where in the brain consciousness exists.15 And the search is still on. At the present, a plausible nominee for the neural substrate of consciousness is one of the most important neurological discoveries of our time. This is that tangle of tiny internuncial neurons called the reticular formation, which has long lain hidden and unsuspected in the brainstem. It extends from the top of the spinal cord through the brainstem on up into the thalamus and hypothalamus, attracting collaterals from sensory and motor nerves, almost like a system of wire-tabs on the communication lines that pass near it. But this is not all. It also has direct lines of command to half a dozen major areas of the cortex and probably all the nuclei of the brainstem, as well as sending fibers down the spinal cord where it influences the peripheral sensory and motor systems. Its function is to sensitize or “awaken” selected nervous circuits and desensitize others, such that those who pioneered in this work christened it “the waking brain.”
The reticular formation is also often called by its functional name, the reticular activating system. It is the place where general anesthesia produces its effect by deactivating its neurons. Cutting it produces permanent sleep and coma. Stimulating it through an implanted electrode in most of its regions wakes up a sleeping animal. Moreover, it is capable of grading the activity of most other parts of the brain, doing this as a reflection of its own internal excitability and the titer of its neurochemistry. There are exceptions, too complicated for discussion here. But they are not such as to diminish the exciting idea that this disordered network of short neurons that connect up with the entire brain, this central transactional core between the strictly sensory and motor systems of classical neurology, is the long-sought answer to the whole problem.
If we now look at the evolution of the reticular formation, asking if it could be correlated with the evolution of consciousness, we find no encouragement whatever. It turns out to be one of the oldest parts of the nervous system. Indeed, a good case could be made that this is the very oldest part of the nervous system, around which the more orderly, more specific, and more highly evolved tracts and nuclei developed. The little that we at present know about the evolution of the reticular formation does not seem to indicate that the problem of consciousness and its origin will be solved by such a study.
Moreover, there is a delusion in such reasoning. It is one that is all too common and unspoken in our tendency to translate psychological phenomena into neuro-anatomy and chemistry. We can only know in the nervous system what we have known in behavior first. Even if we had a complete wiring diagram of the nervous system, we still would not be able to answer our basic question. Though we knew the connections of every tickling thread of every single axon and dendrite in every species that ever existed, together with all its neurotransmitters and how they varied in its billions of synapses of every brain that ever existed, we could still never ? not ever ? from a knowledge of the brain alone know if that brain contained a consciousness like our own. We first have to start from the top, from some conception of what consciousness is, from what our own introspection is. We have to be sure of that, before we can enter the nervous system and talk about its neurology.
We must therefore try to make a new beginning by stating what consciousness is. We have already seen that this is no easy matter, and that the history of the subject is an enormous confusion of metaphor with designation. In any such situation, where something is so resistant to even the beginnings of clarity, it is wisdom to begin by determining what that something is not. And that is the task of the next chapter.