The Divided Brain and the Search for Meaning

by Iain McGilchrist

All understanding is in this sense provisional, a matter of observing similarities and differences

Matter is precisely as hard to explain as consciousness, so that trying to reduce one to the other would not help, even if it were not a strictly meaningless exercise.

I take it that we bring about a world in consciousness that is partly what is given, and partly what we bring, something that comes into being through this particular conjunction and no other. And the key to this is the kind of attention we pay to the world.

What we do not expect to find, we just will not see: much elegant research demonstrates that we are essentially blind to what we do not think is there.

The left hemisphere, as in birds and animals, pays the narrow-beam, precisely focussed, attention which enables us to get and grasp: it is the left hemisphere that controls the right hand with which we grasp something, and controls the aspects of language (not all language) by virtue of which we say we have ‘grasped’ the meaning – made it certain and pinned it down. The right hemisphere underwrites sustained attention and vigilance for whatever may be, without preconception. Its attention is not in the service of manipulation, but in the service of connection, exploration and relation. That is, after all another reason why we reach out a hand – to connect, to create, to share in another's fate, or to explore the world for what it is.

the left hemisphere's raison d'être is to narrow things down to a certainty, the right hemisphere's is to open them up into possibility. In life we need both. In fact for practical purposes, narrowing things down to a certainty, so that we can grasp them, is more helpful. But it is also illusory, since certainty itself is an illusion – albeit, as I say, a useful one. There is no certainty.

I sometimes think of the right hemisphere as what enables Schrödinger's cat to remain on reprieve, and the left hemisphere as what makes it either alive or dead when you open the box. It collapses the infinite web of interconnected possibilities into a point-like certainty for the purposes of our interaction with the world. Although ‘seeing clearly’ is an image of grasping the truth, there is no such thing. At what level of magnification, at what level of description can you be said to have seen something clearly? Is a book seen clearly when it is seen as a whole in your hand, or when you read it, or when you take a magnifying glass to the paper and see the hills and dales of the paper, or when you go further and see the filamentous threads of which the paper is composed, or under electron microscopy, or when it finally resolves into probabilities of the presence of subatomic particles, and reveals itself to be mostly – nothing at all?

Another way of thinking of the difference between the hemispheres is to see the left hemisphere's world as tending towards fixity, whereas that of the right tends towards flow.

the purpose of the left hemisphere is to allow us to manipulate the world, not to understand it.

You can actually see this process happening using brain imaging. The left hemisphere abstracts and generalises, where the right hemisphere's world remains truer to each embodied instance, and appreciates the unique.

neuroscientist V.S. Ramachandran calls the right hemisphere the devil's advocate, because it is always interested in the particular, upsetting the left hemisphere's tendency to collapse unlike into like, and see only what it is expecting to see.

The left hemisphere's world is a representation only. It is like a map, useful precisely because almost all the information about the land to which it refers has been left out.

Here [fig 2] you see in turn a tree as conceived by both hemispheres, by the left hemisphere alone, and then by the right. You will notice that, compared

We are not atoms, nor mixtures, but compounds with rich emergent properties, nowhere dreamed of in the single human heart.

as Aristotle emphasised, there are different kinds of reasoning, different kinds of knowledge, and different modes of understanding appropriate to different areas of life. We do not understand a poem as a doctor understands a patient, and that, in turn, is different from how an accountant understands a business plan. This is not a flaw in poetry, or medical practice, that could be remedied if only it were all rationalised mechanically. The arts and humanities need to remember this: they don't have to feel inferior to science, and try to model themselves on them. Like physicists, but in a quite different way, they are in the ultimately important business of understanding the world and making sense of it, not just learning how to manipulate it.

in The Master and His Emissary, shows that the left hemisphere sees truth as internal coherence of the system, not correspondence with the reality we experience.

hemispheres. As Kant memorably put it, concepts without intuitions are empty, intuitions without concepts are blind.