Volli , sempre volli…

Yale University Press 2=09, copyright Iain McGilchrist

INTRODUCTION

Σ

THE MASTER AND HIS EMISSARY

T</FONT=< FONT>HIS BOOK TELLS A STORY=ABOUT OURSELVES AND THE WORLD, AND ABOUT HO= WE

got to be where we are =ow. While much of it is about the structure of the

human brain – the pla=e where mind meets matter – ultimately it is an attempt to

understand the structur= of the world that the brain has in part created.

Whatever the relationsh=p between consciousness and the brain – unless the

brain plays no </FO=T>role in bringing the=world as we experience it into being, a position

that must have few adhe=ents – its structure has to be significant. It might even

give us clues to unders=anding the structure of the world it mediates, the world we

know. So, to ask a very=simple question, why is the brain so clearly and profoundly

divided? Why, for that =atter, are the two cerebral hemispheres asymmetrical? Do

they really differ in a=y important sense? If so, in what way?

The subject of hemisphe=e differences has a poor track record, discouraging to

those who wish to be su=e that they are not going to make fools of themselves in

the long run. Views on =he matter have gone through a number of phases since it

was first noticed in th= mid-nineteenth century that the hemispheres were not

identical, and that the=e 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 obvious=y having sensory and motor responsibility for, and

control of, the opposit= (or ‘contralateral’) side of the body, language was the

defining difference, th= main specific task of the left hemisphere. The right hemisphere<=P>

was considered to be es=entially ‘silent’. Then it was discovered that, after

all, the right hemisphe=e appeared better equipped than the left hemisphere to

handle visual imagery, =nd 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, p=oved unsatisfactory. Both hemispheres, it is now clear, can

deal with either kind o= material, words or images, in different ways. Subsequent

attempts to decide whic= set of functions are segregated in which hemisphere

have mainly been discar=ed, piece after piece of evidence suggesting that every

identifiable human acti=ity is actually served at some level by both hemispheres.

There is, apparently, v=st redundancy. Enthusiasm for finding the key to hemisphere</P= align="center"

differences has waned, =nd 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 h=s passed into the popular consciousness. These beliefs

could, without much vio=ence to the facts, be characterised as versions of the idea

that the left hemispher= is somehow gritty, rational, realistic but dull, and the right

hemisphere airy-fairy a=d impressionistic, but creative and exciting; a formulation</=>

reminiscent of Sellar a=d Yeatman’s immortal distinction (in their parody of

English history teachin=, 1066 and All Tha=) betw=en the Roundheads – ‘Right

and Repulsive’ – an= the Cavaliers – ‘Wrong but Wromantic’. In reality, both hemispheres

are crucially involved =n reason, just as they are in language; both

hemispheres play their =art in creativity. Perhaps the most absurd of these popular

misconceptions is that =he left hemisphere, hard-nosed and logical, is somehow

male, and the right hem=sphere, dreamy and sensitive, is somehow female. If there

is any evidence that co=ld begin to associate each sex with a single cerebral hemisphere

in this way, it tends t= indicate, if anything, the reverse – but that is another

story and one that I wi=l not attempt to deal with in this book. Discouraged by this

kind of popular travest=, neuroscience has returned to the necessary and unimpeachable</FONT=< P>

business of amassing fi=dings, and has largely given up the attempt to

make sense of the findi=gs, once amassed, in any larger context.

Nonetheless it does not=seem to me likely that the ways in which the hemispheres

differ are simply rando=, dictated by purely contingent factors such as the

need for space, or the =tility of dividing labour, implying that it would work just

as well if the various =pecific brain activities were swapped around between hemispheres</P= align="center"

as room dictates. Fortu=ately, I am not alone in this. Despite the recognition

that the idea has been =ijacked by everyone from management trainers to

advertising copywriters= a number of the most knowledgeable people in the field

have been unable to esc=pe the conclusion that there is something profound here

that requires explanati=n. Joseph Hellige, for example, arguably the world’s bestinformed</=>

authority on the subjec=, writes that while both hemispheres seem to be

involved in one way or =nother in almost everything we do, there are some ‘very

striking’ differences=in the information-processing abilities and propensities of the</P= align="center"

two hemispheres.1 =FONT size="3" face="MinionPro-Regular">

neuroscientist, accepts=that the issue of hemisphere difference has been traduced,

but concludes: ‘The e=istence of such a pop culture shouldn’t cloud the main

issue – the notion th=t the two hemispheres may indeed be specialised for

different functions.’<=TRONG>2 And recently Tim Crow, one of the subtlest and most

sceptical of neuroscien=ists researching into mind and brain, who has often

remarked on the associa=ion between the development of language, functional

brain asymmetry and psy=hosis, has gone so far as to write that ‘except in the light

of lateralisation nothi=g in human psychology/psychiatry makes any sense.’3

</FONT=

There is little doubt t=at the issues of brain asymmetry and hemisphere specialisation

are significant. The qu=stion is only – of what?4

I believe there is, lit=rally, a world of difference between the hemispheres.

Understanding quite wha= that is has involved a journey through many apparently

unrelated areas: not ju=t neurology and psychology, but philosophy, literature and

</=ONT>

the arts,=and even, to some extent, archaeology and anthropology, and I hope the

specialists in these ar=as will forgive my trespasses. Every realm of academic

endeavour is now subjec= to an explosion of information that renders those few

who can still truly cal= themselves experts, experts on less and less. Partly for this

very reason it nonethel=ss seems to me worthwhile to try to make links outside

and across the boundari=s of the disciplines, even though the price may be that

one is always at best a= interested outsider, at worst an interloper condemned to

make mistakes that will=be obvious to those who really know. Knowledge moves

on, and even at any one=time is far from certain. My hope is only that what I have

to say may resonate wit= the ideas of others and possibly act as a stimulus to

further reflection by t=ose better qualified than myself.

I have come to believe =hat the