How Left and Right Brain Explain Our World with Iain McGilchrist (Part 1)

In this episode of Hunger for Wholeness, Sr. Ilia Delio engages renowned psychiatrist and author Dr. Iain McGilchrist. Together, they explore the profound implications of the brain’s divided hemispheres—and how our overreliance on the left brain might be shaping Western culture in unexpected ways.

What happens when we privilege abstract data over embodied experience? When mechanistic thinking crowds out emotional understanding and context? Drawing from his influential works The Master and His Emissary and The Matter with Things, Dr. McGilchrist proposes that the right hemisphere—long neglected—holds the key to restoring balance, wisdom, and connection in our lives and societies.

Later in the episode, Sr. Ilia and Dr. McGilchrist discuss the nature of consciousness, the mystery of mind beyond brain, and the role of implicit knowing in liturgy, love, and the deepest human experiences.

ABOUT IAIN MCGILCHRIST

“What is required is an attentive response to something real and other than ourselves, of which we have only inklings at first, but which comes more and more into being through our response to it – if we are truly responsive to it. We nurture it into being; or not. In this it has something of the structure of love.”

Dr. Iain McGilchrist is a psychiatrist, neuroscience researcher, philosopher and literary scholar. He is a Quondam Fellow of All Souls College, Oxford, an Associate Fellow of Green Templeton College, Oxford, a Fellow of the Royal College of Psychiatrists, and former Consultant Psychiatrist and Clinical Director at the Bethlem Royal & Maudsley Hospital, London. He has been a Research Fellow in neuroimaging at Johns Hopkins Hospital, Baltimore and a Fellow of the Institute of Advanced Studies in Stellenbosch. He has published original articles and research papers in a wide range of publications on topics in literature, philosophy, medicine and psychiatry. He is the author of a number of books, but is best-known for The Master and his Emissary: The Divided Brain and the Making of the Western World (Yale 2009). In November 2021 his two-volume work The Matter with Things: Our Brains, Our Delusions, and the Unmaking of the World was published by Perspectiva Press. www.channelmcgilchrist.com

Whether you're enjoying Hunger for Wholeness or see ways we can improve, we’d genuinely value your feedback. Your insights help us serve our listening community with greater depth and clarity. Visit christogenesis.org/feedback to share your thoughts. Thanks for being part of the journey.

Transcript

Robert: Welcome to Hunger for Wholeness. In today's episode, Ilia speaks with renowned author and psychiatrist Iain McGilchrist. Ilia invites Iain to reflect on his enduring insights, especially what the divide between the brains' hemispheres reveals about the state of Western culture. Our conversation later turns to a deeper question. What distinguishes the brain from the mind?

Ilia: Ian, let me begin because your work, I think, is one of the most important works today in terms of philosophy, in terms of science, and just in terms of anthropology ourselves within a very complexified culture. So can you just for the sake of our listeners, just tell us a little bit about your background, what brought you to write your initial book on that split brain or that divided mind idea and how you have come to develop that through your subsequent works with these two incredible volumes on the matter within things and very interesting on this question of mind and matter. So I'm going to open it up to you.

Iain: Okay, as they say, I have a checkered career. I went up to Oxford actually to study philosophy and theology with the intention of being ordained and quite probably becoming a monk. And none of this happened. When I went for my interview, in order to get into Oxford, I had to sit and examine some subject, which happened to be English literature, which was a love of mine. And my examiner said, "You mustn't do philosophy and theology. It's not an honours degree." Well, believe it or not, in those days, it wasn't an honours degree at Oxford. Whereas now, I believe you can get an honours degree in Frisbee, literally, from some universities. 

So they said, "Why don't you come and study literature? You seem to have a flair for it." We got the knack. So I thought, "Right, I will." And that was fine. And I really, really enjoyed it. And then after I'd finished my undergraduate degree, I took an exam to get a fellowship from All Souls College, Oxford. All Souls is a very odd place. It's the only Oxford or Cambridge College that has no students, not even graduate students. It only has fellows. And the way to get into it in those days was to do a three-day exam, which I did. And I was pleased to succeed in it. And I went on thinking I was going to write more about literature. and then my dissatisfactions with writing about literature—I'm sorry this is relevant, it sounds like a very long way around, but it is relevant to what you're interested in knowing—my dissatisfactions with English became something I thought I wanted to write about from a philosophical point of view. 

And effectively what it was, was that in the seminar room one took an amazing communication from another human being, quite possibly no longer alive, who had written what they had written because they thought it mattered. And in the seminar room, we got cleverer than the author. We always had some theory about what was going on here. I didn't like that at all. We disembodied the work by turning it into an abstract meaning. We got rid of its individual qualities by generalizing and putting it in a genre. And effectively, we made the implicit, where the power of the work lied, entirely explicit. And one was left with a defected body, which had been a living body. Somehow there was only a skeleton left. And so I wrote a book called Against Criticism, which was about my dissatisfactions with the process. One, it's turning the unique into the general, two, turning the implicit into the explicit, and three, making something that is thoroughly embodied, disembodied. And I thought that this was an interesting topic and the most interesting person on this topic at that time was Oliver Sacks. He'd only just written Awakenings. I was very excited in reading that because I thought here is a man who is a practicing doctor who at the same time is a thinker. 

There's a lot of philosophy in that book, a lot of it in asides and footnotes and so on. And he's also got the knack of looking into the individual case and being able to see general truth there. So I thought I’d be somebody like Oliver Sacks. So the first thing to do was to get into a medical school. I spent a year sort of doing the basic sciences. I had maths at a reasonable level at school, but not the sciences. So I did that and cut a long story short, I graduated in medicine. I wanted to do psychiatry because it's where the body and mind meet. And that question really intrigued me. And in my training there, I saw lots of unanswered questions about why the brain should be divided, why it should be asymmetrical, why the corpus callosum, the band of fibers at the base of the brain, should be largely involved in inhibition. What does that tell us? And nobody had a sensible answer, except a colleague, an older colleague called John Cuffing. 

He'd written a remarkable book called The Right Cerebral Hemisphere and Psychiatric Disorders. And I went to a lecture of his one day and afterwards I went up and talked to him because he said so many interesting things. That the left hemisphere, the speaking hemisphere, doesn't understand implicit meaning. The right hemisphere does that. The left hemisphere doesn't preserve uniqueness. It turns everything into exemplars of something general. The left hemisphere is not much in touch with the body. It tends to abstract things from their embodied nature. So I thought, golly, this is fascinating. And putting that together with my unanswered questions about why the brain is structured in this way, I went into 30 years of studying the division between the two hemispheres. There you have it. I was begged by colleagues who had my wellbeing at heart not to do this because it would cause me to crash. My whole career would be annulled and nobody would take me seriously because this topic was known to be just ridiculous psychology. And the thing there is there is a lot of ridiculous psychology. Yes, that is true. But that's not what I was doing. I was trying to find a better answer.

Ilia: So we have opposite careers, actually. You went from science, I went from science to literature in some ways. And we both wind up at the same point in some similar interests, which is very, very interesting. Yeah, that's really, it was quite interesting here. You went from right brain to left brain, I went from left brain to right brain, and we're meeting here in the corpus callosum, which is known as Zoom.

Iain: So what caused you to change from neuroscience to, I think, theology mainly, isn't it? Theology and philosophy.

Ilia: Honestly, it's a short answer, God. In the simplest, I was a materialist in the way that I thought science was the answer to all our deepest questions. And so I was one of those kind of snobbish scientists. I had very little time for the humanities, quite honestly. And I took them because we had to take them, but I felt that they were not challenging enough and not substantive enough in terms of getting to the complexities of life. And so I spent bachelor's, master's, PhD in science, so 13 years studying sciences, and wound up, my master's degree was actually an animal model of schizophrenia. We were looking at, just at that time, dopamine was beginning to be discussed. The drug Elevil was coming into the force. We were looking at dopaminergic receptors and this type of thing. And I worked at a psychiatric hospital for three summers. 

So I was very, very interested in the organic basis of mental illness and what is it that goes on in the brain that causes this dysfunction. And the way people's lives are just really changed by the way neurochemically we can be disrupted. And then I went on to do sort of neurophysiology in the spine. I went from brain to spinal cord actually because the spinal cord is just a smaller circuit. So you can study the circuits more easily. So I worked on a model of Lou Gehrig's disease. You know, how we get to that kind of axonal bundling that blocks nutrition to the distal nerves and this type of thing. 

So your work has just brought back for me immense complexity for one thing and the mystery of the human brain. I mean, even though we know so much more today about it, but the trillions of neurons and glial cells and the fine tuning of this organ, that allows one single movement, like the movement of your finger. And so when you get to the higher levels of personality or decision-making, honestly, I think the more we know, in some ways, the less we know, because I feel like it's kind of an endless search for this mystery. 

So you asked how I got here, so I joined a monastery right after my doctorate. And everyone thought I had sort of a breakdown of some sort, like being in the lab too long. And then I joined eventually a Franciscan order. And I think I just asked too many questions. And they thought the best remedy for me would be to send me to school. And so they asked me to study theology. Actually they asked me to study spirituality. And I didn't really quite know what spirituality was. So I asked to study theology. I had a course in that. I had no idea what I was getting into, but here I am 30 years later as a theologian who works in the area of science and religion. So these areas are bringing them together today is, I think, one of the most important tasks for us to do. When you were talking about language, I always remember the two language centers, the Wernicke and the Baroque as areas of language. And always wondering, how do these two function, for example, in an age of AI and how the brain is making sense of the world and the language we use. 

Language is so important in framing concepts of reality. We're constantly shaping the world. So maybe can you just talk a little bit about these two areas? Like you said, the right brain is sort of the embodied brain, that part of the brain that's kind of connected to the wider world. The left brain is sort of the AI machinic, the machinic world. Do you see that we have sort of a global condition today? Just the way life has complexified, like, has the brain really, are we working a functional dichotomy between these two hemispheres?

Iain: Well, yes, there is a problem with the way in which we see the world is implicit in the title "The Matter with Things" which could be read in at least three ways. Obviously, there's something that is the matter with things and part of it is that we think the world is purely material and that this has nothing to do with consciousness and that we also believe or seem to act as if the world is made up of separate things. Whereas I think what stands forward for us out of the vast range of experiences, things, just elements in a web that attract our attention. So yes, well, I mean, as you point out, Bernicke's area and Broca's area, the receptive and expressive as they were called, areas of speech function, they're both in the left hemisphere. 

There's an enormous amount of language also in the right hemisphere, and two aspects of language that differ from the way in which a computer would understand language by having a rule book and a dictionary. So to the extent that a computer had syntactical rules could make sense grammatically of an utterance and could make another utterance, that is very much left hemisphere based. But there are skills that only the right hemisphere has. Probably the most important of these is the aspect of language called pragmatics, which is what does this utterance in the context actually mean? So there are things that on the surface of it seem to mean one thing, but actually mean another. That might be also through another thing that the right hemisphere is enormously much better at than the left hemisphere, tone of voice. So if I say the simple monosyllable "yes" or "yes" or "yeah", I could do 50 different tones of voice and they'd all mean something different with the same apparent semantic content. But also the right hemisphere understands what is not expressed as important, what is implicit as important, and that is a very big thing because I think that most of our communication with one another is not just on the absolutely literal meaning of the words if they were written down and fed into a computer. 

A lot of times it's a metaphor we've butted, it's a joke of something that's not meant to be taken seriously but is humorous. It might be poetry, it might be liturgy, it might be language as used in a whole range of ways artistically, which is not the same as the way language functions when we read a dishwasher repair manual. So I think all those things are important. At the end of the day, it's the right hemisphere that sees the whole of the utterance in context and is able to interpret it. So for example if we're together in a room and I say, "It's rather hot in here," you know that too. I'm not telling you about the temperature. I'm asking you if you wouldn't mind opening a window. And the right hemisphere understands that, but the left hemisphere doesn't understand why you're telling me something that's quite obvious.

Robert: Spoken language has evolved over millennia and involves far more than simply knowing dictionary definitions. Its complexity raises profound questions. What do we really know? And how do we know it? Yanex asks Iain what epistemological insights he can offer based on his understanding of language and the brain, especially in relation to experiences like love and liturgy. Later, Ilia and Iain explore the distinction between brain and mind, focusing in particular on the contrast between the left and right hemispheres.

Ilia: One thing that you're saying, Ian, is that meaning words that convey meaning are not confined to the literal word itself. So feelings, intuitions, so our understanding, so the knowing process is so much more than the information packed in the bit of a word.

Iain: Absolutely. I make a distinction between the lowest level of communication, which is information, and then there's knowledge, which is where you understand what is happening in a sort of mechanistic way. And then there is understanding, which is putting the whole thing together with everything else you know and what you know of the context and actually getting the gist of what is really being spoken about. So those to get an understanding you need far more than just the ability to, as it were, look the words up in a book.

Ilia: Yeah, and I think this is the difference between knowing as a holistic process of the engaged mind and information. I think knowledge, because it involves feeling, emotion, intuition, perception, in a sense that place of the heart as well as the mind, leads to something more than mere information. So I think real knowledge has to lead to a passion for more life.

Iain: I would agree. And there I draw attention to the different meanings in most languages other than English of different types of knowing. So, for example, I know that Paris is the capital of France, but I know Paris because I spent three years studying that. Actually, I didn't, but for the sake of the argument. And these are quite different knowledge from experience and knowledge of data. And in almost every language that I know other than English, in fact, every other language I know other than English. There are different words for this, these two kinds of knowing. And I think we've got stuck on a very mechanistic version of what language is. Language is also embodied. A single word can activate involuntarily movement or attention to a part of the body. Even reading about something can actually begin to initiate an experience in the brain of whatever it is that's been described in words. 

Also, of course, our thinking is not just going on in the brain. That is the most important place, obviously, for what we know. But there are other parts of the body which take part in our experience and therefore in our knowledge of the world. So it's a wholly different thing from this disembodied abstract connection of symbols. It is actually a living process. And all the things that matter to us most, love, religious faith, friendship, art, architecture, music, poetry, ritual, myth, all these things are most powerful when they are implicit. Once they've been made explicit, they lose their power because they've been turned into something else which is not what the original was.

Ilia: In other words when they're made explicit they're turned into an object of study or an object for you know manipulation or control or however you want whatever we do with that you know which we hold out for us. That's so interesting because I was thinking about liturgy, and the way liturgy, it brings our senses, our feeling, it's so much more like this idea of knowing God is so much more than just an informational data system. There's this kind of holistic taken up in all that we are in this mystery of that which we cannot know, but which we perceive, which we experience deep within us. And in terms of the brain, I mean, years ago, I don't know if you're familiar with Andrew Newberg's work on the mystical mapping, those parts of the brain involved with mystical experience. 

I thought it was quite interesting. And I think it was Ramachandran who spoke of the God neuron or the God particle and locating that area of the religious brain. So we begin to start again, we go into that monastic mode. Can we go into that part of the brain that deals with religious experience, somewhere in the campus or something? And then we kind of lose. we start doing that we lose so this mind, so brain and mind, can you just speak a little bit between brain and mind? Because sometimes we want to understand things, we reduce things to parts in the brain and we lose this sense of mind or something that the brain is embedded in something so much more than just a bunch of neurons and nuclei firing.

Iain: Well yes, I mean one of the most striking things is the case of people who are born effectively without brains, people with hydrocephalus. Hydrocephalus, of course, being when a lot of the space inside the skull is taken up by CSF, cerebrospinal fluid, instead of brain tissue. And there are examples of people who had very little brain. And one case reported by John Lorber was of a young man in his 20s who'd got a first class mathematics degree from Leeds University and an IQ of 126. Was also, socially speaking, quite normal, but had only a thin rim of cortex inside his skull. But even more extraordinary is hydranencephaly, in which there is literally no brain. So you come up the spinal column, you come to the midbrain eventually, but there is no actual cerebrum there. And yet these people, I mean, they've been widely studied. There are not that many of them, but they appear to be able to see things, hear things, have favorite pieces of music, favorite toys, and can read and recognize different people's faces. And this is without a visual cortex without an auditory cortex, that sets one thinking what exactly is happening here. 

I mean, of course, they're not able to do what they would have been able to do had they got a full brain. But it's not just in the brain that experience can be found, which is a point I was making about the gut and the heart. I mean, when I was in medical school, there were fibers that connected the heart to the brain and they were C-fibers, as you know, these are pain-conveying fibers. So obviously the brain needed to know something. And of course there were afferent fibers from the brain to the heart, but these afferent fibers, okay, we understand the pain ones, but there's far, far more than that. It turns out that there's a lot of messages being sent to the brain all the time from the heart and from the gut. The thing I mention to people is that the gut has more neurons in it than the brain of a dog, which is a pretty sophisticated animal. So, and not all just there to enable you to open your bowels or to keep things moving. So, there's a great deal going on and also outside of the neuronal system, there's of course, the effects of hormones. In fact, pretty little parts of the body that are not contributing to our experience in some way. 

And so that's the first thing I'd say about the brain is that it's only one part of what it is that enables us to have experience of the world. It's a very important one, of course. Then of course there is the business of the two hemispheres and their differences. And perhaps I should just say a few words about that because people may think that they've heard about this, and I'd like them to put out of their minds everything that they've heard, because over three decades it's become obvious to me and to everyone else that the things that used to be said are not right. The left hemisphere is not the only one that can do reason, it's not the only one that processes language, as I suggest the right hemisphere plays an important part in particularly in understanding the meaning of utterances. And it's not down to earth and reliable, it's often frankly deluded. So I look in the matter of things quite early on, I look at about 25 to 30 of the best known neuropsychiatric syndromes where people become psychotic. And in almost every case, this syndrome is precipitated by damage to the right hemisphere, not by damage to the left. Nor is it the most intelligent hemisphere, the right hemisphere is more intelligent not just in emotional and social intelligence, but actually in cognitive intelligence IQ terms. 

So all of the stuff that people may have heard is wrong. The right hemisphere is not airy-fairy and unreliable. It happens to see a great deal more and to understand a great deal more than the left hemisphere. And it is better in touch with emotion, but it's not emotional in some detrimental sense. In fact, expression of emotion that is inappropriate to the context or exaggerated is inhibited by the right hemisphere and not by the left. So we're very badly off if we don't understand how much we rely on the right hemisphere. 

And the reason there are these differences between the hemispheres, not the ones that we used to say, which I've just said are not true, are to do with attention. That's a fascinating topic. It's a fascinating topic from a theological, philosophical point view as well. The two hemispheres have evolved to be distinct. They're not entirely separate, although the big connection at the base of the brain, the corpus callosum, only begins with mammals. So all earlier species of creatures didn't have that connection. They had other very fine commissures, but nothing in the order of the corpus callosum. 

And the reason that these two hemispheres or two types or modules of neurons need to be kept separate in all creatures we've looked at is because they attend to the world in two wholly different ways. The left hemisphere prioritises getting things, using stuff, and this of course is very important for staying alive. First of all you have to be able to catch or pick up food and you need to do that fairly swiftly and deftly, and for this it targets whatever it is that it needs and locks onto that. But if that's the only kind of attention it pays, it won't survive, because at the same time it needs to pay an exact opposite kind of attention, which is broad and looking at the whole picture in a sustained way, having vigilance, whereas the left hemisphere is busy picking up a seed, catching a rabbit, doing whatever it is doing in order to manipulate the world. So I sometimes say that the left hemisphere apprehends the world in the sense of grasping onto it, which is what ad prehendere literally means. And the right hemisphere comprehends the world, in other words, takes together what it knows to make sense of it and really to understand it. 

And so the differences between the hemispheres are that the left hemisphere sees the world made up of bits because it's targeted piecemeal, little bits, one and another. See what connects them. It's only interested in their utility. It doesn't see that they're always changing and flowing. It thinks that they're fixed and so that it can grab its attention literally sort of like the Gorgon's stare, it mobilizes what it is so that it can grab it neatly and quickly. It doesn't understand implicit meaning. It doesn't really understand animacy. It sees it simply as mechanisms. 

And so if you suppress somebody's right hemisphere, they will start seeing living creatures as machines or inanimate objects or zombies. So it's seeing a very special kind of world, one that is a represented world. In other words, it is latching on to what is left in the mind after something is no longer present. It can't be represented in the sense of being present again, but it is represented. And that's a very different thing from the original element. This is what Wordsworth wrote about, that when he was a child, he saw everything in all its immediacy and its glory as something awe-inspiring. As he got older, as he went to the left hemisphere, he'd say, "Yes, I've got it, picturesque scene. Yes, another waterfall for my collection," etc. It couldn't actually be there with the presence of the thing and be inspired by it. So that's what the left hemisphere brings up, this very mechanistic, very diminished, rather unintelligent, but useful pitch. 

And the right hemisphere has a quite different picture, which is of things that are always interconnected, that are never precisely known, that are largely implicit, that have human meaning and animate in many cases, and are fully present. So these are very different ways of experiencing the world. And in short, it seems to me that we've got locked into a way of looking at the world as is typical of the left hemisphere, and we're denying that there is anything else there. Very convenient. If you don't understand it, just say it doesn't exist.

Ilia: Yeah, what you said here in about 15 minutes could be now a whole course.

Robert: We'll pick up the conversation next time as Ilia and Iain delve even deeper into the left-right brain distinction, exploring how Iain interprets our societal struggles through the lens of brain science, consciousness, and even prayer. I'm Robert Nicastro. Thanks for listening.