The Master and His Emissary Introduction

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The Master and His Emissary Introduction

Author: Iain McgilChrist Publisher: London, UK: Yale University Press. Publish Date: 2010 Review Date: Status:📚

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The subject of hemisphere differences has a poor track record, discouraging to those who wish to be sure that they are not going to make fools of themselves in the long run. Views on the matter have gone through a number of phases since it was first noticed in the mid-nineteenth century that the hemispheres were not identical, and that there seemed to be a clear asymmetry of function related to language, favouring the left hemisphere. At first, it was believed that, apart from each hemisphere obviously having sensory and motor responsibility for, and control of, the opposite (or ‘contralateral’) side of the body, language was the defining difference, the main specific task of the left hemisphere. The right hemisphere was considered to be essentially ‘silent’. Then it was discovered that, after all, the right hemisphere appeared better equipped than the left hemisphere to handle visual imagery, and this was accepted as the particular contribution it made, its equivalent to language: words in the left hemisphere, pictures in the right. But that, too, proved unsatisfactory. Both hemispheres, it is now clear, can deal with either kind of material, words or images, in different ways. Subsequent attempts to decide which set of functions are segregated in which hemisphere have mainly been discarded, piece after piece of evidence suggesting that every identifiable human activity is actually served at some level by both hemispheres. There is, apparently, vast redundancy. Enthusiasm for finding the key to hemisphere differences has waned, and it is no longer respectable for a neuroscientist to hypothesise on the subject.

This is hardly surprising, given the set of beliefs about the differences between the hemispheres which has passed into the popular consciousness. These beliefs could, without much violence to the facts, be characterised as versions of the idea that the left hemisphere is somehow gritty, rational, realistic but dull, and the right hemisphere airy-fairy and impressionistic, but creative and exciting; a formulation reminiscent of Sellar and Yeatman’s immortal distinction (in their parody of English history teaching, 1066 and All That) between the Roundheads – ‘Right and Repulsive’ – and the Cavaliers – ‘Wrong but Wromantic’. In reality, both hemispheres are crucially involved in reason, just as they are in language; both hemispheres play their part in creativity. Perhaps the most absurd of these popular misconceptions is that the left hemisphere, hard-nosed and logical, is somehow male, and the right hemisphere, dreamy and sensitive, is somehow female. If there is any evidence that could begin to associate each sex with a single cerebral hemisphere in this way, it tends to indicate, if anything, the reverse – but that is another story and one that I will not attempt to deal with in this book. Discouraged by this kind of popular travesty, neuroscience has returned to the necessary and unimpeachable business of amassing findings, and has largely given up the attempt to make sense of the findings, once amassed, in any larger context.

Despite the recognition that the idea has been hijacked by everyone from management trainers to advertising copywriters, a number of the most knowledgeable people in the field have been unable to escape the conclusion that there is something profound here that requires explanation. Joseph Hellige, for example, arguably the world’s best-informed authority on the subject, writes that while both hemispheres seem to be involved in one way or another in almost everything we do, there are some ‘very striking’ differences in the information-processing abilities and propensities of the two hemispheres.1 V. S. Ramachandran, another well-known and highly regarded neuroscientist, accepts that the issue of hemisphere difference has been traduced, but concludes: ‘The existence of such a pop culture shouldn’t cloud the main issue – the notion that the two hemispheres may indeed be specialised for different functions.’2 And recently Tim Crow, one of the subtlest and most sceptical of neuroscientists researching into mind and brain, who has often remarked on the association between the development of language, functional brain asymmetry and psychosis, has gone so far as to write that ‘except in the light of lateralisation nothing in human psychology/psychiatry makes any sense.’3

What is it they do that is so different? Well, I will argue, nothing much: it is quite true that almost everything we once thought went on in one or other hemisphere alone is now known to go on in both.5 So where does that leave the pursuit of hemisphere differences? Right on track. The whole problem is that we are obsessed, because of what I argue is our affiliation to left-hemisphere modes of thought, with ‘what’ the brain does – after all, isn’t the brain a machine, and like any machine, the value of it lies in what it does? I happen to think this machine model gets us only some of the way; and like a train that drops one in the middle of the night far from one’s destination, a train of thought that gets one only some of the way is a liability. The difference, I shall argue, is not in the ‘what’, but in the ‘how’ – by which I don’t mean ‘the means by which’ (machine model again), but ‘the manner in which’, something no one ever asked of a machine. I am not interested purely in ‘functions’ but in ways of being, something only living things can have.

One of the more durable generalisations about the hemispheres has been the finding that the left hemisphere tends to deal more with pieces of information in isolation, and the right hemisphere with the entity as a whole, the so-called Gestalt – possibly underlying and helping to explain the apparent verbal/visual dichotomy, since words are processed serially, while pictures are taken in all at once. But even here the potential significance of this distinction has been overlooked. Anyone would think that we were simply talking about another relatively trivial difference of limited use or interest, a bit like finding that cats like to have their meat chopped up into small bits, whereas dogs like to wolf their meat in slabs. At most it is seen as helpful in making predictions about the sort of tasks that each hemisphere may preferentially carry out, a difference in ‘information processing’, but of no broader significance. But if it is true, the importance of the distinction is hard to over-estimate. And if it should turn out that one hemisphere understands metaphor, where the other does not, this is not a small matter of a quaint literary function having to find a place somewhere in the brain. Not a bit. It goes to the core of how we understand our world, even our selves, as I hope to be able to demonstrate.

Things change according to the stance we adopt towards them, the type of attention we pay to them, the disposition we hold in relation to them. This is important because the most fundamental difference between the hemispheres lies in the type of attention they give to the world. But it’s also important because of the widespread assumption in some quarters that there are two alternatives: either things exist ‘out there’ and are unaltered by the machinery we use to dig them up, or to tear them apart (naïve realism, scientific materialism); or they are subjective phenomena which we create out of our own minds, and therefore we are free to treat them in any way we wish, since they are after all, our own creations (naïve idealism, post-modernism).

The kind of attention we pay actually alters the world: we are, literally, partners in creation. This means we have a grave responsibility, a word that captures the reciprocal nature of the dialogue we have with whatever it is that exists apart from ourselves.

the relationship between the hemispheres does not appear to be symmetrical, in that the left hemisphere is ultimately dependent on, one might almost say parasitic on, the right, though it seems to have no awareness of this fact. Indeed it is filled with an alarming self-confidence. The ensuing struggle is as uneven as the asymmetrical brain from which it takes its origin.

Because I am involved in redressing a balance, I may at times seem to be sceptical of the tools of analytical discourse. I hope, however, it will be obvious from what I say that I hold absolutely no brief for those who wish to abandon reason or traduce language. The exact opposite is the case. Both are seriously under threat in our age, though I believe from diametrically opposed factions. The attempt by some post-modern theoreticians to annex the careful anti-Cartesian scepticism of Heidegger to an anarchic disregard for language and meaning is an inversion of everything that he held important. To say that language holds truth concealed is not to say that language simply serves to conceal truth (though it certainly can do), or, much worse, that there is no such thing as truth (though it may be far from simple). But equally we should not be blind to the fact that language is also traduced and disregarded by many of those who never question language at all, and truth too easily claimed by those who see the subject as unproblematic. It behoves us to be sceptical. Equally this book has nothing to offer those who would undermine reason, which, along with imagination, is the most precious thing we owe to the working together of the two hemispheres. My quarrel is only with an excessive and misplaced rationalism which has never been subjected to the judgment of reason, and is in conflict with it. I hope it will not be necessary for me to emphasise, too, that I am in no sense opposed to science, which, like its sister arts, is the offspring of both hemispheres – only to a narrow materialism, which is not intrinsic to science at all. Science is neither more nor less than patient and detailed attention to the world, and is integral to our understanding of it and of ourselves.

It might seem reductive to link the highest achievements of the human mind, in philosophy and the arts, to the structure of the brain. I believe it is not.

the way we experience the world, and even what there is of the world to experience, is dependent on how the brain functions: we cannot escape the fact, nor do we need to try. At the most basic, some things that we know to be potential objects of experience – sounds at particularly high or low frequencies, for example – are not available to us, though they may be to bats and bears; and that’s simply because our brains do not deal with them. We know, too, that when parts of the brain are lost, a chunk of available experience goes with them. But this is not to hold that all that exists is in the brain – in fact, it demonstrates that that cannot be the case; nor is it to say that mental experience is just what we can observe or describe at the brain level.

OK, but if my purpose is to understand the world better, why do I not just deal with mind, and forget about the brain? And in particular why should we be concerned with the brain’s structure? That may be of academic interest to scientists, but as long as it carries on working, does it really matter? After all, my pancreas is doing fine, without my being able to remember much about its structure. However one conceives the relationship of mind and brain – and especially if one believes them to be identical – the structure of the brain is likely to tell us something we otherwise could not so easily see. We can inspect the brain only ‘from the outside’ (even when we are probing its innermost reaches), it is true: but we can inspect the mind only ‘from within’ (even when we seem to objectify it). Seeing the brain’s structure is just easier. And since structure and function are closely related, that will tell us something about the nature of our mental experience, our experience of the world. Hence I believe it does matter.

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although I begin by looking at brain structure in relation to the neuropsychological functions that we know are associated with each hemisphere, my aim is purely to illuminate aspects of our experience.

Freud anticipated that making connections between experience and the structure of the brain would be possible once neuroscience became sufficiently evolved. A neurologist first and foremost, he believed that the mental entities that he described, and whose conflicts shaped our world – the id, the ego and the superego – would one day be more precisely identified with structures within the brain.7 In other words he believed that the brain not merely mediated our experience, but shaped it too. When we look at our embodied selves, we look back into the past. But that past is no more dead than we are. The past is something we perform every living day, here and now. That other founding father of psychoanalysis, Jung, was acutely aware of this, and surmised that much of our mental life, like our bodies, has ancient origins:

Just as the human body represents a whole museum of organs, with a long evolutionary history behind them, so we should expect the mind to be organized in a similar way … We receive along with our body a highly differentiated brain which brings with it its entire history, and when it becomes creative it creates out of this history – out of the history of mankind … that age-old natural history which has been transmitted in living form since the remotest times, namely the history of the brain structure.8

The brain has evolved, like the body in which it sits, and is in the process of evolving. But the evolution of the brain is different from the evolution of the body. In the brain, unlike in most other human organs, later developments do not so much replace earlier ones as add to, and build on top of, them.9 Thus the cortex, the outer shell that mediates most so-called higher functions of the brain, and certainly those of which we are conscious, arose out of the underlying subcortical structures which are concerned with biological regulation at an unconscious level; and the frontal lobes, the most recently evolved part of the neocortex, which occupy a much bigger part of the brain in humans than in our animal relatives, and which grow forwards from and ‘on top of’ the rest of the cortex, mediate most of the sophisticated activities that mark us out as human – planning, decision making, perspective taking, self-control, and so on. In other words, the structure of the brain reflects its history: as an evolving dynamic system, in which one part evolves out of, and in response to, another.

it turns out that there is after all coherence to the way in which the correlates of our experience are grouped and organised in the brain, and we can see these ‘functions’ forming intelligible wholes, corresponding to areas of experience, and see how they relate to one another at the brain level, this casts some light on the structure and experience of our mental world. In this sense the brain is – in fact it has to be – a metaphor of the world.

The great physiologist, Sir Charles Sherrington, observed a hundred years ago that one of the basic principles of sensorimotor control is what he called ‘opponent processors’.10 What this means can be thought of in terms of a simple everyday experience. If you want to carry out a delicate procedure with your right hand that involves a very finely calibrated movement to the left, it is made possible by using the counterbalancing, steadying force of the left hand holding it at the same time and pushing slightly to the right. I agree with Marcel Kinsbourne that the brain is, in one sense, a system of opponent processors. In other words, it contains mutually opposed elements whose contrary influence make possible finely calibrated responses to complex situations. Kinsbourne points to three such oppositional pairings within the brain that are likely to be of significance. These could be loosely described as ‘up/down’ (the inhibiting effects of the cortex on the more basic automatic responses of the subcortical regions), ‘front/back’ (the inhibiting effects of the frontal lobes on the posterior cortex) and ‘right/left’ (the influence of the two hemispheres on one another).11

When I say the ‘left hemisphere does this’, or ‘the right hemisphere does that’, it should be understood that in any one human brain at any one time both hemispheres will be actively involved. Unless one hemisphere has been surgically removed, or otherwise destroyed, signs of activity will be found in both. Both hemispheres are involved in almost all mental processes, and certainly in all mental states: information is constantly conveyed between the hemispheres, and may be transmitted in either direction several times a second. What activity shows up on a scan is a function of where the threshold is set: if the threshold were set low enough, one would see activity just about everywhere in the brain all the time. But, at the level of experience, the world we know is synthesised from the work of the two cerebral hemispheres, each hemisphere having its own way of understanding the world – its own ‘take’ on it. This synthesis is unlikely to be symmetrical, and the world we actually experience, phenomenologically, at any point in time is determined by which hemisphere’s version of the world ultimately comes to predominate. Though I would resist the simplistic idea of a ‘(left or right) hemisphere personality’ overall, there is evidence I will look at later that, certainly for some kinds of activities, we consistently prefer one hemisphere over the other in ways that may differ between individuals, though over whole populations they tend to cohere. For two reasons, even small differences in potential between the hemispheres at quite a low level may lead to what are large shifts at a higher level. For one thing, as Ornstein has suggested, at the level of moment-to-moment activity the hemispheres may operate a ‘winner takes all’ system – that is, if one hemisphere is 85 per cent as efficient at a task as the other, we will not tend to divide the work between them in a ratio of 0.85:1.00, but consistently use whichever is better to do the whole job.12 On those occasions where the ‘wrong’ hemisphere does get in first, however, and starts to take control, at least for not very demanding tasks, it will most probably continue to trump the other hemisphere, even if the other hemisphere would have been a better choice at the outset – possibly because the time costs of sharing or transferring control are greater than the costs of continuing with the current arrangement.13

Ornstein, 1997, p. 16.
Sergent, 1982.

The other is that, though such winner-takes-all effects may still be individually small, a vast accumulation of many small effects could lead ultimately to a large bias overall, especially since repeated preference for one hemisphere helps to entrench still further an advantage that may start out by being relatively marginal. To the extent that a process goes on usefully in one hemisphere, it reinforces the sending of information preferentially to that hemisphere in the future. ‘Small initial differences between the hemispheres could compound during development, ultimately producing a wide range of functional asymmetries, via a “snowball” mechanism.’14 The hemispheres are thus involved in differentiating themselves.

Laeng, Chabris & Kosslyn, 2003, p. 313.

‘The universe is built on a plan, the profound symmetry of which is somehow present in the inner structure of our intellect.’19 This remark of the French poet Paul Valéry is at one and the same time a brilliant insight into the nature of reality, and about as wrong as it is possible to be. In fact the universe has no ‘profound symmetry’ – rather, a profound asymmetry. More than a century ago Louis Pasteur wrote: ‘Life as manifested to us is a function of the asymmetry of the universe … I can even imagine that all living species are primordially, in their structure, in their external forms, functions of cosmic asymmetry.’20 Since then physicists have deduced that asymmetry must have been a condition of the origin of the universe: it was the discrepancy between the amounts of matter and antimatter that enabled the material universe to come into existence at all, and for there to be something rather than nothing. Such unidirectional processes as time and entropy are perhaps examples of that fundamental asymmetry in the world we inhabit. And, whatever Valéry may have thought, the inner structure of our intellect is without doubt asymmetrical in a sense that has enormous significance for us.

Note: the imperfect nature of reaity is what allows anything to extst. if it were perfect, there would only be nothingness

As I have said, I believe that there are two fundamentally opposed realities rooted in the bihemispheric structure of the brain. But the relationship between them is no more symmetrical than that of the chambers of the heart – in fact, less so; more like that of the artist to the critic, or a king to his counsellor. There is a story in Nietzsche that goes something like this.21 There was once a wise spiritual master, who was the ruler of a small but prosperous domain, and who was known for his selfless devotion to his people. As his people flourished and grew in number, the bounds of this small domain spread; and with it the need to trust implicitly the emissaries he sent to ensure the safety of its ever more distant parts. It was not just that it was impossible for him personally to order all that needed to be dealt with: as he wisely saw, he needed to keep his distance from, and remain ignorant of, such concerns. And so he nurtured and trained carefully his emissaries, in order that they could be trusted. Eventually, however, his cleverest and most ambitious vizier, the one he most trusted to do his work, began to see himself as the master, and used his position to advance his own wealth and influence. He saw his master’s temperance and forbearance as weakness, not wisdom, and on his missions on the master’s behalf, adopted his mantle as his own – the emissary became contemptuous of his master. And so it came about that the master was usurped, the people were duped, the domain became a tyranny; and eventually it collapsed in ruins.22

The meaning of this story is as old as humanity, and resonates far from the sphere of political history. I believe, in fact, that it helps us understand something taking place inside ourselves, inside our very brains, and played out in the cultural history of the West, particularly over the last 500 years or so. Why I believe so forms the subject of this book. I hold that, like the Master and his emissary in the story, though the cerebral hemispheres should co-operate, they have for some time been in a state of conflict. The subsequent battles between them are recorded in the history of philosophy, and played out in the seismic shifts that characterise the history of Western culture. At present the domain – our civilisation – finds itself in the hands of the vizier, who, however gifted, is effectively an ambitious regional bureaucrat with his own interests at heart. Meanwhile the Master, the one whose wisdom gave the people peace and security, is led away in chains. The Master is betrayed by his emissary.

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The Master and His Emissary Introduction

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