* 'Philosophy of commonsense: accepting primary beliefs of mankind as ultimate criterion of truth' (The Concise Oxford Dictionary).
I have suggested that the evils of mankind are caused, not by the primary aggressiveness of individuals, but by their self-transcending identification with groups whose common denominator is low intelligence and high emotionality. We now come to the parallel conclusion that the delusional streak running through history is not due to individual forms of lunacy, but to the collective delusions generated by emotion-based belief-systems. We have seen that the cause underlying these pathological manifestations is the split between reason and belief -- or more generally, insufficient co-ordination between the emotive and discriminative faculties of the mind. Our next step will be to inquire whether we can trace the cause of this faulty co-ordination -- this disorder in the hierarchy -- to the evolution of the human brain. Should contemporary neurophysiology, though still in its infancy, be able to provide some indication of the causes of the trouble, we would have made a first step towards a frank diagnosis of our predicament and thereby gain some inkling of the direction in which the search for a remedy must proceed.
Summary
The considerations set out in earlier chapters led us to distinguish three factors in emotion: nature of the drive, hedonic tone, and the polarity of the self-assertive and self-transcending tendencies.
Under normal conditions the two tendencies are in dynamic equilibrium. Under conditions of stress the self-assertive tendency may get out of control and manifest itself in aggressive behaviour. However, on the historical scale, the damages wrought by individual violence for selfish motives are insignificant compared to the holocausts resulting from self-transcending devotion to collectively shared belief-systems. It is derived from primitive identification instead of mature social integration; it entails the partial surrender of personal responsibility and produces the quasi-hypnotic phenomena of group-psychology. The egotism of the social holon feeds on the altruism of its members. The ubiquitous rituals of human sacrifice at the dawn of civilisation are early symptoms of the split between reason and emotion-based beliefs, which produces the delusional streak running through history.
XVI
THE THREE BRAINS
I have no inclination to keep the domain of the psychological floating as it were in the air, without any organic foundation . . . Let the biologists go as far as they can and let us go as far as we can. Some day the two will meet. Freud
Let me recapitulate: when one contemplates the streak of insanity running through human history, it appears highly probable that homo sapiens is a biological freak, the result of some remarkable mistake in the evolutionary process. The ancient doctrine of original sin, variants of which occur independently in the mythologies of divene cultures, could be a reflection of man's awareness of his own inadequacy, of the intuitive hunch that somewhere along the line of his ascent something has gone wrong.
Mistakes in Brain-Making
The strategy of evolution, like any other strategy, is subject to trial and error. There is nothing particularly improbable in the assumption that man's native equipment, though superior to that of any known animal species, nevertheless may contain some serious fault in the circuitry of his most precious and delicate instrument -- the central nervous system.
Whether a skylark is happier than a rainbow trout is a nice debating point; both are stagnant species, but well adapted to their ways of life, and to call them evolutionary mistakes because they have not got the brains to write poetry would be the height of hubris. When the biologist talks of evolutionary mistakes, he means something more tangible and precise: some obvious deviation from Nature's own standards of engineering efficiency, a construction fault which deprives an organ of its survival value -- like the monstrous antlers of the Irish elk. Some turtles and insects are so top-heavy that if in combat or by misadventure they fall on their back, they cannot get up again, and starve to death -- a grotesque error in construction which Kafka turned into a symbol of the human predicament. But before talking of man, I must discuss briefly two earlier evolutionary mistakes in brain-building, both of which had momentous consequences.
The first concerns the brain development of the arthropods which, with more than seven hundred thousand known species, constitute by far the largest phylum of the animal kingdom. They range from microscopic mites through centipedes, insects and spiders to ten-foot giant crabs; but they all have this in common, that their brains* are built around their gullets. In vertebrates, the brain and spinal cord are both dorsal -- at the back of the alimentary canal. In invertebrates, however, the main nerve chain runs ventrally -- on the belly side of the animal. The chain terminates in a ganglionic mass beneath the mouth. This is the phylogenetically older part of the brain; whereas the newer and more sophisticated part of it developed above the mouth, in the vicinity of the eyes or other distance-receptors. Thus the alimentary tube passes through the midst of the evolving brain-mass, and this is very bad evolutionary strategy because, if the brain is to grow and expand, the alimentary tube will be more and more compressed (see Figure 11). To quote Gaskell's The Origin of Vertebrates:
Progress on these lines must result in a crisis, owing to the inevitable squeezing out of the food-channel by the increasing nerve-mass. . . . Truly, at the time when vertebrates first appeared, the direction and progress of variation in the Arthropoda was leading, owing to the manner in which the brain was pierced by the oesophagus, to a terrible dilemma -- either the capacity for taking in food without sufficient intelligence to capture it, or intelligence sufficient to capture food and no power to consume it. [1] * In lower forms the ganglionic masses which are precursors of the brain.
Top: relation between the alimentary canal (A) and nervous system (B) of an invertebrate. The upper brain mass (c) and the lower brain mass (d) constrict the alimentary canal (after Wood Jones and Porteus). Bottom: section across the brain of a scorpion-like invertebrate. The upper and lower brain masses (c and d) constrict the narrow alimentary tube (A) in the centre of the brain (after Gaskell).
The dilemma seems to have been particularly acute for 'the highest scorpion and spider-like animals, whose brain-mass has grown round and compressed the food-tube so that nothing but fluid pabulum can pass through into the stomach; the whole group have become blood-suckers. These kinds of animals -- the sea-scorpions -- were the dominant race when the vertebrates first appeared. . . . Further upward evolution demanded a larger and larger brain with the ensuing consequence of a greater and greater difficulty of food supply.' [2] Another authority, Wood Jones, comments:
To become a blood-sucker is to become a failure. Phylogenetic senility comes with the specialisation of blood-sucking. Phylogenetic death is sure to follow. Here, then, is an end to the progress in brain building among the invertebrates. Faced with the awful problem of the alternatives of intellectual advance accompanied by the certainty of starvation, and intellectual stagnation accompanied by the inability of enjoying a good square meal, they must perforce elect the latter if they are to live. The invertebrates made a fatal mistake when they started to build their brains around the oesophagus. Their attempt to develop big brains was a failure. . . . Another start must be made. [3]
The failure is reflected by the fact that even in the highest forms of invertebrates -- the social insects behaviour is almost entirely governed by instinct; learning by experience plays a relatively small part. And since all members of the beehive are descended from the same pair of parents with no discernible varieties in heredity, they have little individuality: insects are not persons. Admiration for the marvellous organisation of the beehive should not blind us to this fact. In vertebrates, on the other hand, as we ascend the evolutionary ladder, individual learning plays an increasing role compared to instinct -- thanks to the increase in size and complexity of the brain, which was free to grow without imposing on us a diet of porridge.
The second cautionary tale concerns our old friends, the mars
upials. I have called them the poor cousins of us piacentals, because each species of pouched animal, from mouse to wolf, is of an inferior 'make' compared to its opposite number in the placental series. Wood Jones (himself an Australian) comments regretfully: '. . . They are failures. Wherever marsupial meets higher mammal, it is the marsupial that is circumvented by superior cunning and forced to retreat or to succumb. The fox, the cat, the dog, the rabbit, the rat and the mouse are all ousting their parallels in the marsupial phylum.' [4]
The reason is simple: the brains of the marsupials are not only smaller, but of a vastly inferior construction. The ring-tailed opossum and the bush-baby lemur are both arboreal and nocturnal animals with certain similarities in size, appearance and habits. But in the opossum, a marsupial, about one-third of the cerebral hemispheres is given to the sense of smell -- sight, hearing and all higher functions are crowded together in the remaining two-thirds. The placental lemur, on the other hand, has not only a larger brain, though its body is smaller than the opossum's, but the area devoted to smell in the lemur's brain has shrunk to relative insignificance, giving way, as it should, to areas serving functions that are more vital to an arboreal creature.
When the marsupials took to the trees, smell ought to have become unimportant to them compared to the distance receptors, sight and hearing, and their nervous system ought to have reflected the change. But in contrast to our ancestors, the placental tree-dwellers, this change failed to take place in the marsupials. Moreover, an important component is lacking in the brain of the higher marsupials, the so-called corpus callosum. This is a conspicuous nerve tract which, in placentaIs, connects the 'new' (non-olfactory) areas of the right and left cerebral hemispheres. It obviously plays a vital integrative part, though the details of its functioning are still somewhat problematical,* and its absence from the marsupial brain seems to have been a principle factor in their arrested development.
* Some humans were found at autopsies to have been born without a true corpus callosum -- yet were apparently none the worse for it.
The point where that development comes to an end is the koala bear. It is, to quote Wood Jones again, 'the largest and most perfectly adapted tree-dwelling marsupial. In bulk we may compare it with the Patas monkey.' [5] But, compared to the monkey, the koala cuts a very poor figure: 'In the koala the tree-climber has become a tree-clinger. Hands have turned into hooks; and fingers are not used for plucking fruit or leaves or testing novel objects, but for fixing the animal, by virtue of the long curved claws, to the tree upon which it clings.' [6]
It cannot do otherwise because its principal sense is still smell, which is of little use in an arboreal creature. Like Quoodle, the koala thinks with his nose. His brain weighs only one-seventh of the monkey's; and most of it is occupied by the smell area which in the monkey has virtually vanished; while the non-smell areas of the koala have no corpus callosum to connect them. The koala is the end of the marsupial line of evolution, left behind clinging to his eucalyptus tree like a discarded hypothesis -- while his monkey cousin is only the beginning of the evolution from primate to man. It is a fascinating speculation whether, if the marsupials had been equipped with a corpus callosum, they would have evolved into a pouched parallel to man, as they have evolved into pouched parallels of the flying squirrel and the wolf.
'A Tumorous Overgrowth'
But before congratulating ourselves on having such a superior brain which does not strangle our oesophagus or condemn us to live by smell, we ought to pause and examine the possibility that man, too, might carry a constructional fault inside his skull, perhaps even more serious than the arthropod and marsupial precedents; a constructional error which potentially threatens his extinction -- but which might still be corrected by a supreme effort of self-repair.
The first reason for this suspicion is the extraordinary rapidity of the evolutionary growth of the human brain -- a feat, as we know, unique in evolutionary history. To quote Professor Le Gros Clark: 'It now appears from the fossil record that the hominid brain did not begin to enlarge significantly before the beginning of the Pleistocene, but from the middle Pleistocene [circa half a million years ago] onwards it expanded at a most remarkable speed -- greatly exceeding the rate of evolutionary change which had so far been recorded in any anatomical character in lower animals. . . . The rapidity of the evolutionary expansion of the brain during the Pleistocene is an example of what has been termed "explosive evolution".' [7]
Next, let me quote from Judson Herrick's The Evolution of Human Nature:
The history of civilisation is a record of slow but dramatic enrichment of human life interspersed with episodes of wanton destruction of all the accumulated riches of property and spiritual values. These episodic reversions to bestiality seem to be increasing in virulence and in the magnitude of the resulting disasters until now we are threatened with the loss of everything that has been won in our struggle for the better life. In view of this record it has been suggested that the enlargement of the human brain has gone so fast and so far that the result is actually pathological. Normal behaviour depends upon the preservation of a balanced interplay between integrating and disintegrating factors and between the total pattern and local partial patterns. So, it is claimed, the human cortex is a sort of tumorous overgrowth that has got so big that its functions are out of normal control and 'race' erratically like a steam engine that has lost its governor. This ingenious theory was published by Morley Roberts and quoted with apparent approval by Wheeler. [8] Their arguments seem to be plausible in view of the past history of wars, revolutions, and crumbled empires, and the present world-wide turmoil that threatens total destruction of civilisation. But the theory is neurological nonsense. [9]
In the form stated here it certainly is. It cannot be the size of the cortex alone which 'puts its function out of normal control'. We must look for a more plausible cause.
The cause which contemporary research seems to indicate is not increase in size, but insufficient co-ordination between archi-cortex and neocortex -- between the phylogenetically old areas of our brain, and the new, specifically human areas which were superimposed on it with such unseemly haste. This lack of co-ordination causes, to use a phrase coined by P. MacLean, a kind of 'dichotomy in the function of the phylogenetically old and new cortex that might account for differences between emotional and intellectual behaviour'. [10] While 'our intellectual functions are carried on in the newest and most highly developed part of the brain, our affective behaviour continues to be dominated by a relatively crude and primitive system. This situation provides a clue to understanding the difference between what we feel and what we know. . . .' [11]
Let us look a little closer at what is implied in these statements by an eminent contemporary neurophysiologist.
The Physiology of Emotion
The distinction between 'knowing' and 'feeling', between reason and emotion, goes back to the Greeks. Aristotle in De Anima pointed to visceral sensations as the substance of emotion and contrasted them with the form, i.e., the ideational content of the emotion. The intimate connection between emotion and the viscerae is a matter of common experience, and has always been taken for granted by laymen and physicians alike: we know that emotional arousal affects heartbeat and pulse; that fear stimulates the sweat glands, grief the tear glands, and the respiratory, digestive, not to mention the reproductive, systems are all involved in the experience of emotion. So much so that the word 'visceral' was originally used to refer to strong emotional feelings, including fear ('he has no guts') and pity ('the bowels of mercy').
Well into the eighteenth century, the medical profession adhered to the Galenic doctrine, according to which thoughts circulated in the brain, emotions circulated in the vessels of the body. At the beginning of the nineteenth century, this ancient dualism yielded to a more modern version: in his immensely influential books, Anatomie Générale and Recherches Physiologiques sur la Vie et la Mort, Xavier Bichat drew a fundamental distinction between the cere
bro-spinal nervous system, including the brain and spinal cord, which looked after all the external transactions of the animal with its environment; and the 'ganglionic', now called autonomic nervous system, which controlled all organs serving internal functions. The first was governed by a single centre, the brain; but the second, Bichat thought, was governed by a great number of 'little brains', such as the solar plexus, in various parts of the body. The cerebro-spinal nervous system was held to be responsible for all voluntary action; the autonomic, governing the viscera, was beyond voluntary control; and so were the passions or emotions which all belonged to the visceral domain.
Bichat's doctrine reigned for a whole century; it was proved wrong in many, if not most, details; but the distinction he made between the functions of the two systems, and their correspondence with the ancient dualism between thought and emotion, is still valid in broad outlines. Nobody, of course, believes any longer that the experience of emotion is located in 'little brains' in the vicinity of the heart and bowels. All experience is centralised in the brain, including the control of the autonomic system which looks after visceral function. As one would expect, the viscera are controlled by a phylogenetically very ancient structure in the brain-stem, the region of the hypothalamus (thalamus: Greek for inner chamber or woman's apartment). This is the crucial area, in close proximity to the pituitary gland and to the vestiges of the primitive smell-brain, which regulates visceral and glandular functions beyond voluntary control, and is intimately connected with emotional experience.