The Ghost in the Machine

  On the next higher level are the networks of sensory-motor skills and habits -- such as touch-typing or driving a car, which are performed more or less mechanically, and do not require the attention of the highest centres -- unless some disturbance throws them out of gear. Driving a car is a routine which includes, among its 'rules of the game', stepping on the brake pedal when there is an obstacle ahead. But on an icy road braking can be a risky affair, the steering wheel has a different feel, and the whole strategy of driving must be altered -- transposed into a different key, as it were. After a while this, too, may become a semi-automatic routine; but let a little dog amble across the icy road in front of the driver, and he will have to make a 'top-level decision' whether to slam down the brake, risking the safety of his passengers, or run over the dog. And if, instead of a dog, the jaywalker is a child, he will probably resort to the brake, whatever the outcome. It is at this level, when the pros and cons are equally balanced, that the subjective experience of freedom and moral responsibility arises.

  Feedbacks and Homeostasis

  But the ordinary routines of existence do not require such moral decisions, and not even much conscious attention. The physiological processes breathing, digestion, etc. -- look after themselves: they are self-regulating. And so are most routine activities: walking, bicycling, driving a car. The principle of self-regulation is in fact fundamental to the hierarchic concept. If a holon is to function as a semi-autonomous sub-whole, it must be equipped with self-regulatory devices. In other words, its operations must be guided, on the one hand, by its own fixed canon of rules and on the other had by pointers from a variable environment. Thus there must be a constant flow of information concerning the progress of the operation back to the centre which controls it; and the controlling centre must constantly adjust the course of the operation according to the information fed back to it. This is the principle of "feedback control".* The principle is old -- James Watt had already used it in his steam-engine to keep its velocity steady under varying conditions of load. But its modern applications, under the name of "cybernetics", have been remarkably successful in the most varied fields, from physiology to computing machines -- another case of pulling lively rabbits out of an old hat.

  * Feedback is generally defined as the coupling of the output to the input.

  The simplest illustration of feedback control is thermostatically regulated central heating. You set the thermostat in the living room at the desired temperature. If the temperature falls below it, the thermostat activates an electrical circuit, which in turn increases the rate of burning in the heating plant. If it gets too hot in the room, the opposite process takes place. The plant in the cellar controls the temperature in the room; but the information sent back to it by the thermostat in the room corrects the function of the plant, and keeps it steady. Another obvious example is the servo-mechanism which keeps a ship on a steady course by automatically counteracting any deviation from it. Hence the term 'cybernetics' -- from the Greek cybernitos = helmsman.

  The living organism is also controlled by a thermostatic device, which keeps its temperature at a stable level -- with variations rarely exceeding one centigrade, more or less. The seat of the thermostat is in the hypothalamus, a vital structure in the brain-stem. One of its functions is to maintain homeostasis -- a steady body temperature, pulse rate, and chemical balance of body fluids. The microscopic thermostat in the brain-stem has been shown to react to local temperature changes of a hundredth of a centigrade. When the temperature in its immediate vicinity -- on the ear-drum -- exceeds a critical level, sudden sweating sets in. Conversely, when the temperature falls, the muscles automatically start to shiver, converting energy into heat. Other 'homeostats' (a term coined on the analogy of the thermostat) control other physiological functions, and keep the organism's milieu interieur -- its 'inner environment' -- on a stable level.

  We thus have precise evidence for self-regulating mechanisms operating at the basic levels of the hierarchy. The word 'homeostasis' was coined by Walter B. Cannon, the great Harvard physiologist, who had a clear grasp of its hierarchic implications. He wrote that homeostasis liberates the organism 'from the necessity of paying routine attention to the management of the details of bare existence. Without homeostatic devices, we should be in constant danger of disaster, unless we were always on the alert to correct voluntarily what normally is corrected automatically. With homeostatic devices, however, that keep essential bodily processes steady, we as individuals are free from such slavery -- free to . . . explore and understand the wonders of the world about us, to develop new ideas and interests, and to work and play, untramelled by anxieties concerning our bodily affairs.' [2]

  Self-regulating devices are found not only on the visceral level; they operate on every level of an organism's activities. A boy riding a bicycle, a tightrope-walker balancing himself with his bamboo stick, are perfect examples of kinetic homeostasis. But each depends on constant kinesthetic feedback -- on sensations reporting the movements, tensions, postures of his own body. When the feedback stops, homeostasis breaks down. The next quotation is from Norbert Wiener, who coined the term 'cybernetics', and put the concept of feedback on the map:

  A patient comes into a neurological clinic. He is not paralysed, and he can move his legs when he receives the order. Nevertheless, he suffers under a severe disability. He walks with a peculiar, uncertain gait, with eyes downcast, on the ground and on his legs. He starts each step with a kick, throwing each leg in succession in front of him. If blindfolded, he cannot stand up, and totters to the ground. What is the matter with him? . . . [He] suffers from tabes dorsalis. The part of the spinal cord which ordinarily receives sensations has been damaged or destroyed by the late sequelae of syphilis. The incoming messages are blunted, if they have not totally disappeared. The receptors in the joints and tendons and muscles and the soles of his feet which ordinarily convey to him the position and state of motion of his legs send no messages which his central nervous system can pick up and transmit, and for information concerning his posture he is obliged to trust his eyes and the balancing organs of his inner ear. In the jargon of the physiologist, he has lost an important part of his proprioceptive or kinaesthetic sense. [3]

  In other words, the patient's sensory hierarchy, which provides the feedback to the controlling centre, has been impaired. All sensory-motor skills, from riding a bicycle to touch-typing and piano-playing, operate by means of feedback loops, provided by the complex networks which connect the two branches of the hierarchy.

  But let us beware of using the principle of feedback control as a magic formula which explains everything -- as computer theoreticians occasionally tend to do. The concept of feedback, without the concept of hierarchic order, is like the grin without the cat. We have seen that the performance of a skill follows a pre-set pattern, according to certain rules of the game. These are fixed, but sufficiently elastic to permit constant adjustments to variable environmental conditions. Feedback can only operate within the limits of those fixed rules -- the 'canon' of the skill. The part which feedback plays is to report back on every step in the progress of the operation, whether it is overshooting or falling short of the mark, how to keep it on an even keel, when to intensify the pace and when to stop. But it cannot alter the intrinsic pattern of the skill. The tit building its nest has a conception of its shape somehow represented in its nervous system -- otherwise the nests of all tits would not be alike; the constant feedback it receives through eye and touch merely tells the bird when 'weaving' should stop and be followed by 'trampling', and when that should be followed by 'lining'. One of the vital differences between the S-R concept and the present theory is that according to the former, the environment determines behaviour, whereas according to the latter, feedback from the environment merely guides or corrects or stabilises a pre-existing pattern of behaviour.

  The primacy and autonomy of such patterns of instinct-behaviour have been strongly emphasised in recent years by ethologists like L
orenz, Tinbergen, Thorpe, etc., and by biologists like v. Bertalanffy and Paul Weiss.* Our acquired skills display the same autonomy. As I am writing these lines, I am getting a constant feedback of the pressure of pen against paper through my fingers, and of the progress of the script through my eyes. But these do not alter the pattern of my handwriting, they merely keep it on an even keel; for, even with closed eyes, my writing will merely get shaky, but its pattern will remain unmistakably the same.

  * e.g., P. Weiss: 'The structure of the input does not produce the structure of the output, but merely modifies intrinsic nervous activities which have a structural organisation of their own.' [4] Or, v. Bertalanffy: 'The stimulus (that is, an alteration of external conditions) does not cause a process in an internally inactive system, but rather modifies the process in an internally active system.' [5]

  Loops within Loops

  So far I have talked about sensory feedback guiding motor activities. But the cross-traffic in the network works both ways, and perception is guided by the intervention of motor activities. Seeing is inextricably mixed up with motion -- from the large motions of head and eyeballs, down to the involuntary minute eye motions -- drift, flicker, tremor -- without which we cannot see at all. Similarly with hearing: if you try to recall a tune, to reconstruct its auditory image, what do you do? You hum it. The perceptual and motor hierarchies are so intimately correlated on every level that to draw a sharp distinction between 'stimulus' and 'response' becomes arbitrary and meaningless. Both have been swallowed up by feedback loops, along which impulses run in circles like kittens chasing their tails.*

  * 'Because stimulus and response are correlative and contemporaneous, the stimulus processes must be thought of not as preceding the response, but rather as guiding it to a successful [conclusion]. That is to say, stimulus and response must be considered as aspects of a feedback loop' (Miller et al. [6]).

  Let me illustrate this by a celebrated experiment. A cat's auditory nerve was wired to an electric apparatus so that nerve impulses transmitted from the ear to the brain could be heard in a loudspeaker. A metronome was kept going in the room, and its clicks, as transmitted by the cat's auditory nerve, and amplified by the apparatus, were clearly audible. But when a mouse in a jar was brought into the room, the cat not only lost interest in the metronome, as one would expect, but the impulses in its auditory nerve became feebler or stopped altogether. This is a dramatic example of how the admission of stimuli at a peripheral receptor-organ -- the outermost Kremlin gate -- can be controlled from the centre.

  The lesson taught by this and similar experiments can be best summed up by way of an anecdote. In the good old days before the turn of the century, Vienna had a mayor, called Lueger, who professed to a mild form of anti-semitism. But he also cultivated a number of Jewish friends. When taken to task over this by one of his cronies, Lueger gave the classic answer: 'I am the Burgomaster, and I decide who is a Jew and who is not.' Mutatis mutandum, the cat watching the mouse and turning a deaf ear to the metronome may just as well have said: It's I who decide what is a stimulus and what is not.'

  A Holarchy of Holons

  Let us carry this inquiry into the meaning of current terminology a step further, and ask just what that convenient word 'environment' is meant to signify.

  When I am driving my car along a country road, the environment in contact with my right foot is the accelerator-pedal, and the environment in contact with my left foot is the clutch-pedal. The elastic resistance to pressure of the accelerator provides a tactile feedback which helps to keep the speed of the car steady, while the clutch controls another invisible environment, the gearbox. The feel of the wheel under my hands acts like a servo-mechanism to keep a straight course. But my eyes encompass a much larger environment than my feet and my hands; it determines the overall strategy of driving. Thus the hierarchically organised creature that I am is in fact functioning in a hierarchy of environments, guided by a hierarchy of feedbacks.

  One advantage of this interpretation is that the hierarchy of environments can be extended indefinitely. When a chess player stares at the board in front of him, the environment in which his thoughts operate is determined by the distribution of chess-men on the board. Assume that the situation allows twenty possible moves permitted by the rules of the game, and that five of these look promising. He will consider each in turn. A good player may be able to think at least three moves ahead -- by which time the game would have branched out into a great variety of possible situations, each of which the player must try to visualise in order to decide on his initial move. In other words, he is guided by feedbacks from an imagined board, in an imagined environment. Most of our thinking, planning and creating operates in imaginary environments.

  We have seen, however, that all our perceptions are coloured by imagination. Thus the difference between 'real' and 'imaginary' environments becomes a matter of degrees -- or rather of levels, ranging from the unconscious phenomena of projecting figures into the Rohrschach blot, to the chess master's uncanny powers of inventing the future. Which is just another way of repeating that the hierarchy is open at the top.

  To sum up this chapter in a formula, we may say that the organism in its structural and functional aspects is a hierarchy of self-regulating holons which function (a) as autonomous wholes in supra-ordination to their parts, (b) as dependent parts in sub-ordination to controls on higher levels, (c) in co-ordination with their local environment.

  Such a hierarchy of holons should rightly be called a holarchy -- but, remembering Ben Jonson's warning, I shall spare the reader this further neologism.

  VIII

  HABIT AND IMPROVISATION

  All good things which exist are the fruits of originality. John Stuart Mill

  The somewhat technical character of the preceding chapters and the frequent use of engineering terms like 'input', 'output', 'triggers', 'scanners' and the rest, might have aroused in the reader the uneasy suspicion that the author is trying to replace one mechanistic model by another mechanistic model, the concept of man as a conditioned automaton by a concept of man as a hierarchic automaton. In fact, however, we are gradually -- though perhaps rather painfully -- moving towards a way out of the trap of mechanistic determinism. The escape hatch, so to speak, is at that 'open end' at the top of the hierarchy, to which I have repeatedly referred, although the meaning of this metaphor can emerge only gradually.

  It will perhaps become a little clearer if we consider the appearance of more complex, more flexible and less predictable forms of behaviour on successively higher levels of a hierarchy. Conversely, with each step down to lower levels, we find increasingly mechanised, stereotyped and predictable behaviour-patterns. When one is writing a gossipy letter to a friend, it is difficult to foretell what will come into one's head next; the choice of possible alternatives is very large. Once you have decided what to say next, the number of alternative ways of saying it is still large, but nonetheless more restricted by the rules of grammar, the limits of one's vocabulary, etc. Finally, the muscle-contractions, which depress the typewriter keys, are stereotyped and could as well be carried out by a robot. In the language of the physicist, we would say that a sub-skill, or holon, on the n level of the hierarchy has more 'degrees of freedom' (a larger variety of alternative choices permitted by the rules) than a holon on the (n - 1) level.

  Let me briefly recapitulate some points from earlier chapters: every skill (or habit) has a fixed and a variable aspect. The former is determined by its canon, the 'rules of the game', which lend it its characteristic pattern -- whether the game is making a spider's web, constructing a bird's nest, ice-skating, or playing chess. But the rules permit a certain variety by alternative choices: the web can be suspended from three or four points of attachment, the nest can be adjusted to the angle of the fork in the branch, the chess-player has a vast choice among permissible moves. These choices, having been left open by the rules, depend on the lie of the land, the local environment in which the holon operate
s -- they are a matter of strategy, guided by feedbacks. Put in a different way, the fixed code of rules determines the permissible moves, flexible strategy determines the choice of the actual moves among the permissible ones. The larger the number of alternative choices, the more complex and flexible the skill. Vice versa, if there is no choice at all, we reach the limit case of the specialised reflex. Thus rigidity and flexibility are opposite ends of a scale which applies to every type of hierarchy; and in every case we shall find that flexibility increases, rigidity decreases, as we move upward to higher levels.

  The Origins of Originality

  In the instinctive behaviour of animals, we find at the bottom end of the scale monotonously repeated patterns of courting and threatening, mating and fighting -- rigid, compulsive rituals. Sometimes, when the animal is frustrated, these rituals are performed pointlessly on the wrong occasion. Cats will go through the motion of burying their faeces on the kitchen tiles. Young squirrels, reared in captivity, when given nuts will go through the motions of burying them in the bottom of the wire cage, 'and then go away contented, even though the nuts are exposed to full view' (Thorpe [1]).

  At the opposite end of the scale we find very complex and flexible skills displayed by mammalians like chimpanzees and dolphins -- but also by insects and fishes. Ethologists have produced impressive evidence to show that under favourable circumstances even insects are capable of behaving in ways which could not be predicted from the creature's known repertory of skills, and which fully deserve to be called 'ingenious' or 'original'. Professor Baerends, for instance,* has spent years on an exhaustive study of the activities of the digger wasp. [1a] The female of this species lays her eggs in holes which she digs in the ground. She provisions the holes first with caterpillars then, when the eggs have hatched, with moth larvae; then with more caterpillars, until she finally closes the hole. Now the point is that each female has to look after several holes at the same time, the inhabitants of which are in different phases of development, and thus need different diets. She not only provides each according to its needs, but when a hole is robbed of its supplies by the experimenter, promptly replenishes it. Another wasp builds clusters of clay-cells, lays an egg in each, provides it with provisions for the future, then seals the cell -- much as the Egyptians used to do with Pharaoh's burial chambers. If now the experimenter makes a hole in the cell -- something quite unprecedented in the wasp's scheme of things -- she will first pick up the caterpillars which have fallen out, and stuff them back through the hole, then set about mending the cell with pellets of clay -- a repair job which she has never done before. But that is not the end of it. Hingston has described the exploits of another type of wasp in a crisis. He made a hole in a cell in a fiendish way, so that it could not be repaired from the outside. But this species of wasp always works from the outside. The wasp wrestled with the task for two hours, until night came and she had to give up. Next morning she flew straight to the damaged cell, and set about repairing it by a new method: 'she examines it from both sides and then, having made a choice, elects to do the repair from within.' [2]