The Master and His Emissary: The Divided Brain and the Making of the Western World

by Iain McGilchrist

I don’t believe in the left brain/right brain myth: I believe in discovering the truth about hemisphere difference.

I also did not mean to imply that the changes in cultural balance were due to there having been gross changes in our brains over the time periods in question (the last 2,500 years). Given that we are evolving creatures, it is bound to be true that our brains have changed at some level, since our brains both mould and are in turn moulded by the culture in which we live.

What I suggest is that nowadays we use – draw on the potential of – our brains differently from the way in which we have used them at different periods in the past, periods which also differ from one another in this same respect.

Nor do I suggest that the causes of such cultural shifts can be reduced to neuroscience. There are many causative factors in play when cultures change, including sociological, psychological, environmental, epigenetic, technological, economic and political factors, all of which are interconnected.

I am not attempting to answer the question of what causes changes: just of what patterns are discernible when such changes occur, and how those patterns relate to the possible takes on the world afforded to us by the brain’s bihemispheric structure. Doing so gives us insight into those situations – I believe we are in one now – where the balance is lost. It helps us see what it is we are missing.

I make no claim to be a Freud or a Darwin, but I do see clearly that my hypothesis is in this respect more like Darwin’s than Freud’s. It certainly can act as a philosophical model that reconfigures our knowledge in a way that I believe is richer. But it is derived from, and can be tested against, empirical, experimental observations.

Even on sustained introspection, we can be only indirectly aware of the fact that reality is constructed from two incompatible world views. This fact becomes manifest, however, in the disputes of philosophers and theologians over the ages about the very nature of reality. By such indirect routes we become aware of fundamental irreconcilables in the world, irreconcilables so marked that they have led philosophers, time and again, to conclude that we are ‘citizens of two worlds’ – though those worlds were never fully articulated.

If a neuropsychologist had to choose three things to characterise most clearly the functional contribution of the right hemisphere, they would most probably be the capacity to read the human face, the capacity to sustain vigilant attention, and the capacity to empathise.

I think there are, again, several reasons why this characteristic entrenchment occurs, and indeed is likely to occur whenever a civilisation passes its peak.

First, the left-hemisphere view is designed to aid you in grabbing stuff. Its purpose is utility and its evolutionary adaptation lies in the service of grasping and amassing ‘things’.

We live in an era where articulating and making explicit are of increasing importance and are treated as a mark of truth, and their inverse treated with increasing suspicion. Partly this is another sign of the ‘move to the left hemisphere’ that I am describing, but that is not the only reason for it: it is also necessitated by large-scale movements of populations with different languages and cultures, as well as the sheer size of modern urban societies in which one can no longer rely on much that was once taken for granted in smaller and more closely knit communities.

The right hemisphere’s view is inclusive, ‘both/and’, synthetic, integrative; it realises the need for both. The left hemisphere’s view is exclusive, ‘either/or’, analytic and fragmentary – but, crucially, unaware of what it is missing. It therefore thinks it can go it alone.

in an era where truth seems to be up for grabs, the question of what we can rely on as true seems ever more pressing. In particular, I believe that reductionism has become a disease, a viewpoint lacking both intellectual sophistication and emotional depth, which is blighting our ability to understand what is happening and what we need to do about it.

There are, it seems to me, four main pathways to the truth: science, reason, intuition and imagination.

And that means that we should be appropriately sceptical of the left hemisphere’s vision of a mechanistic world, an atomistic society, a world in which competition is more important than collaboration; a world in which nature is a heap of resource there for our exploitation, in which only humans count, and yet humans are only machines – not even very good ones, at that; a world curiously stripped of depth, colour and value.

I believe there is, literally, a world of difference between the hemispheres. Understanding quite what that is has involved a journey through many apparently unrelated areas: not just neurology and psychology, but philosophy, literature and the arts, and even, to some extent, archaeology and anthropology, and I hope the specialists in these areas will forgive my trespasses.

the most fundamental difference between the hemispheres lies in the type of attention they give to the world.

Nonetheless 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.

Because the right hemisphere sees nothing in the abstract, but always appreciates things in their context, it is interested in the personal, by contrast with the left hemisphere, which has more affinity for the abstract or impersonal.168 The right hemisphere’s view of the world in general is construed according to what is of concern to it, not according to objective impersonal categories, and therefore has a personal quality. This is both its strength and its weakness in relation to the left hemisphere.

Not only does the right hemisphere have an affinity with whatever is living, but the left hemisphere has an equal affinity for what is mechanical.

Although there has been much debate about the particular emotional timbre of each hemisphere (of which more shortly), there is evidence that in all forms of emotional perception, regardless of the type of emotion, and in most forms of expression, the right hemisphere is dominant.

Those with right-hemisphere damage have difficulty understanding emotional intonation or implication.229 Curiously it seems that the left hemisphere reads emotions by interpreting the lower part of the face. Though the left hemisphere can understand emotional display, it looks not at the eyes, even when directed to do so, but at the mouth.230 The right hemisphere alone seems to be capable of understanding the more subtle information that comes from the eyes. Empathy is not something one reads in the lower face, where relatively blunt messages – friend or foe – tend to be conveyed.

When it comes to the understanding (and expression) of emotion in language, again, despite left-hemisphere preponderance for language, the right hemisphere is superior.231 Emotional language may be possible even when speech is lost through a left-hemisphere stroke.232 It is the right hemisphere that understands the emotional or the humorous aspect of a narrative.233 Memory for emotional language is in the right hemisphere.234 Ultimately there is clear evidence that when it comes to recognising emotion, whatever it may be, whether it is expressed in language or through facial expression, it is the right hemisphere on which we principally rely.

The right hemisphere clearly does play a role in arithmetical calculations,320 and, in general, mathematical calculations activate more strongly on the right.321 Addition and subtraction activate the right parietal lobe, whereas multiplication activates verbal remembrance of ‘times tables’ in the left hemisphere.

While we are gathering new information, the right hemisphere is responsible, but once whatever it is becomes thoroughly ‘known’, familiar, it is taken over by the left hemisphere.

Plenty of animals show, in their degree, capacity to deduce (deductive reasoning is importantly associated with right-hemisphere function, in any case): crows can reason, even bees have language of a kind. Of course, even the most highly evolved animals are incomparably inferior to ourselves in both respects, but the point is that they do show at least glimmerings of such, utilitarian, functions. But there are many things of which they show no evidence whatsoever: for instance, imagination, creativity, the capacity for religious awe, music, dance, poetry, art, love of nature, a moral sense, a sense of humour and the ability to change their minds.

The most fundamental observation that one can make about the observable universe, apart from the mysterious fact that it exists at all – prompting the ultimate question of philosophy, why there is something rather than nothing – is that there are at all levels forces that tend to coherence and unification, and forces that tend to incoherence and separation. The tension between them seems to be an inalienable condition of existence, regardless of the level at which one contemplates it. The hemispheres of the human brain, I believe, are an expression of this necessary tension. And the two hemispheres also adopt different stances about their differences: the right hemisphere towards cohesion of their two dispositions, the left hemisphere towards competition between them.

Marian Annett, perhaps the greatest living authority on handedness, believes that we may have developed ‘over-dependence on the left hemisphere at the expense of right hemisphere skills’. She points to the unexpectedly large number of left-handers amongst artists, athletes, and ‘skilled performers of many kinds’.146 A marked difference between the performance of the two hands in right-handers is associated with a slight improvement in the right hand, but the price for this, according to Annett, is that ‘the left hand declines dramatically’, a finding that has been corroborated by many other researchers.

The fact that a place is special to some because of its great peace and beauty may, by that very fact, make it for another a resource to exploit, in such a way that its peace and beauty are destroyed. Attention has consequences.

Rather the point is that philosophy in the West is essentially a left-hemisphere process.2 It is verbal and analytic, requiring abstracted, decontextualised, disembodied thinking, dealing in categories, concerning itself with the nature of the general rather than the particular, and adopting a sequential, linear approach to truth, building the edifice of knowledge from the parts, brick by brick.

The idea that the conscious mind is passive in relation to what comes to it through the right hemisphere, and from whatever-it-is-that-exists beyond, is also expressed by Jung: ‘Everyone knows nowadays that people “have complexes”. What is not so well known, though far more important theoretically, is that complexes can have us.’

Heidegger saw the disasters of Western materialism as stemming from a ‘forgetting of Being’, and the apparently opposed forces of capitalism and communism as merely variants in a common technicity and exploitation of nature. Our attempts to force nature according to our will are futile, he thought, and show no understanding of Being. This might sound like a pious reflection, and one that does not tally with reason. But there is meaning here that even the left hemisphere can understand. The domination and massive despoliation of nature and natural resources, the reduction of the world to commodity, has not led to the happiness it was designed to yield.

If one had to encapsulate the principal differences in the experience mediated by the two hemispheres, their two modes of being, one could put it like this. The world of the left hemisphere, dependent on denotative language and abstraction, yields clarity and power to manipulate things that are known, fixed, static, isolated, decontextualised, explicit, disembodied, general in nature, but ultimately lifeless. The right hemisphere, by contrast, yields a world of individual, changing, evolving, interconnected, implicit, incarnate, living beings within the context of the lived world, but in the nature of things never fully graspable, always imperfectly known – and to this world it exists in a relationship of care.

There is a tendency for the life sciences to consider a mechanistic universe more ‘real’, even though physics long ago moved away from this legacy of nineteenth-century materialism, with the rather odd result that the inanimate universe has come to appear animate, to take part in mind, while the animate universe appears inanimate, mindless. Science has to prioritise clarity; detached, narrowly focussed attention; the knowledge of things as built up from parts; sequential analytic logic as the path to knowledge; and the prioritising of detail over the bigger picture. Like philosophy it comes at the world from the left hemisphere’s point of view. And the left hemisphere’s version of reality works well at the local level, the everyday, on which we are focussed by habit.

The paradox of philosophy is that we need to get beyond what can be grasped or explicitly stated, but the drift of philosophy is always and inevitably back towards the explicit.

Too much self-awareness destroys not just spontaneity, but the quality that makes things live; the performance of music or dance, of courtship, love and sexual behaviour, humour, artistic creation and religious devotion become mechanical, lifeless, and may grind to a halt if we are too self-aware. Those things that cannot sustain the focus of conscious attention are often the same things which cannot be willed, that come only as a by-product of something else; they shrink from the glare of the left hemisphere’s world.

But the laws of non-contradiction, and of the excluded middle, which have to rule in the left hemisphere because of the way it construes the nature of the world, do not hold sway in the right hemisphere, which construes the world as inherently giving rise to what the left hemisphere calls paradox and ambiguity. This is much like the problem of the analytic versus holistic understanding of what a metaphor is: to one hemisphere a perhaps beautiful, but ultimately irrelevant, lie; to the other the only path to truth.

I am not committed to the view that the brain is the driver of culture, any more than I am to the view that culture is the driver of brain development. They will inevitably mould each other. But one of the constraints on how we see the world has to be the balancing of the options given to us by the two cerebral hemispheres. These constitute relatively stable differences over the length of human history. Cultural shifts can exploit such options: but hemisphere differences would still constrain the options available to the human mind.

Today all the available sources of intuitive life – cultural tradition, the natural world, the body, religion and art – have been so conceptualised, devitalised and ‘deconstructed’ (ironised) by the world of words, mechanistic systems and theories constituted by the left hemisphere that their power to help us see beyond the hermetic world that it has set up has been largely drained from them. I have referred to the fact that a number of influential figures in the history of ideas, among them Nietzsche, Freud and Heidegger, have noted a gradual encroachment over time of rationality on the natural territory of intuition or instinct.

It is conceivable that, were it possible to scan the brain of pre-Achaean humans – say, in the eighth century BC – one might find some small, but possibly measurable, differences in the structure, or more probably in the functioning, of the brain, compared with the brains of those who lived 1,000 years earlier, or with the modern human brain. But such changes could take place only over very long time scales. As to what is actually happening in the brain when the more recent ‘swings’, those of the last five hundred years or so, take place, nothing is visible (at least nothing on a scale that we could actually measure). Is there anything going on at the brain level at all? I think the answer is ‘yes’.

Classical natural selection, which depends on the very slow process of random mutation, with environmental selective pressures then acting over generations to favour certain mutations above others, requires long periods of time. It is just about conceivable that this operated in the ancient Greek situation, since this arose on the back of the incursion of a new population into the central Mediterranean at this time, with a different gene pool. In that sense this change is quite different from those that came afterwards in modern Europe.

(and, still more, of course, Eastern cultures). Genetic shifts might also explain the extraordinary decline which followed the overrunning of the Roman Empire by Goths, Huns and Franks in the fourth and fifth centuries AD, since, however much one may admire aspects of life in what used to be called the Dark Ages, effectively whole ways of thinking and being, whole aspects of the phenomenological world, simply disappeared in the West for nearly a thousand years.

But the later evolution of ideas, from the Renaissance on, is simply not susceptible to this kind of argument, because the time periods are far too short, and there aren’t any major migrations of population that I’m aware of that might change the European gene pool sufficiently.

But imitation would always work faster, so that in the end what we chose to imitate would govern which epigenetic mechanisms got selected (e.g. a culture in which we learnt to think and speak of ourselves in more computer-like ways would lead to selection for the ‘geek’ brain), rather than the genes that got selected dictating what we imitated.

Human choices appear to be open, but the existence of free will remains hard to argue for, though some have made sophisticated cases based on an understanding of the realms of theoretical physics in which cause and effect cede to probabilities and uncertainties. I am not able to evaluate these properly. Viewed from the phenomenological point of view, however, we feel ourselves to be free, though being pulled, drawn, attracted forward towards and by things that have a sort of magnetic power (such as archetypes), rather than pushed or prodded forward by what’s happened.

We have, then, become free to choose our own values, our ideals. Not necessarily wisely, of course. This process could be commandeered by the left hemisphere again if it could only persuade us to imitate and acquire left-hemisphere ways of being in the world. That is what I believe has happened in recent Western history. In our contemporary world, skills have been downgraded and subverted into algorithms: we are busy imitating machines.

In 1973, Chris McManus and Nick Humphrey had already published in Nature the results of a study of approximately 1,400 Western portrait paintings from the sixteenth to twentieth centuries, showing that there is a tendency during this period, also, for the sitter to be portrayed looking to the viewer’s left.6 These findings have since been confirmed by others.7 The implication appears to be that the focus of interest comes to lie in the viewer’s left visual field (preferentially subserved by the right hemisphere), at the same time that the more emotionally expressive left hemiface of the subject (controlled by the subject’s right hemisphere) is exposed to view. The strength of Hufschmidt’s research, apart from the enormous scale of his undertaking, is his inclusion of the ancient world. This reveals a distinct shift towards favouring the right hemisphere in the appreciation of representations of the human face from the sixth century BC onwards.

In summary, therefore, whereas Brener would see overall a straightforward opposition of the two hemispheres, with a perhaps hard-to-explain advance in right-hemisphere functions at the expense of the left occurring at this time, I would see a rise in bilateral frontal lobe function initially, which both necessitates an advance of the left hemisphere to underwrite the ‘distance’ involved and, through the creation of necessary distance, enables the right hemisphere to expand its capacity. I do not deny the evidence of right-hemisphere advance, simply relate it differently to the roles of the left hemisphere and frontal lobes.

The problem with this is that all the evidence suggests that schizophrenia is a relatively modern disease, quite possibly existent only since the eighteenth century or thereabouts, and that its principal psychopathological features have nothing to do with regression towards irrationality, lack of self-awareness, and a retreat into the infantile realm of emotion and the body, but entail the exact opposites: a sort of misplaced hyper-rationalism, a hyper-reflexive self-awareness, and a disengagement from emotion and embodied existence.

For Heraclitus logos, the ultimate reason, cause, meaning, or deep structure of the world, is not some power that lies somewhere behind appearances, as it later would become, but is what Kahn calls a ‘phenomenal property’, evidenced and experienced in reasoned thought and responses to the world.50 If we are enabled to attend to experience, rather than to our pre-conceived ideas about experience, we encounter, according to Heraclitus, the reality of the union of opposites. Appreciating this coming together, wherein all opposing principles are reconciled, was the essence of sophia (wisdom, the root of philosophy) for Heraclitus.51 Opposites define one another and bring one another into existence.