Semir Zeki Full Interview Transcript


Ard: I wanted to ask a question that I read on your blog recently. You talked about how colour is perceived, and this has to do, partially, with the way our brains are structured. So the structure to our brains allows us to see colour in certain ways, and then there’s also a structure to our brain that allows us to perceive mathematics in certain ways. And that’s clearly evolved over time.

SZ: Yes, well, look, I think we have to go a step back and ask, what is the function of the brain? Now, there are a lot of functions which you can impute to the brain – individual functions: seeing, hearing, working out solutions, acting and so on. But there is one primordial, overall function, which is to acquire knowledge about the world. Now, here is the most important philosophical question of all: to obtain that knowledge, you have to stabilise the world. You cannot obtain that knowledge unless you can stabilise it. Now, in colour vision, what does stabilising it mean? It means that you have to get rid of all the continual changes in the wavelength anti-composition of the light coming from surfaces. You have to discard these and assign a constant colour to a surface.

David: When you say ‘stabilising reality or the colour’, what do you mean by that?

SZ: Well, I’ll give you an example. If we look at green leaves in a park, we see these green leaves as green, at noon on a cloudy day or a sunny day. If you look at them at dawn or at dusk, you’ll still see them as green. If you were to measure the amount of red, green and blue light reflected from these leaves in these different conditions, you find vast differences, and indeed, at dawn and at dusk, they’ll reflect more red light.

Now, how does the brain stabilise the world so that you can see it only as green? It takes the amount of red, green and blue light reflected from that leaf, and the amount of red, green and blue light reflected from the surround. It takes those ratios – those ratios never change.

So whatever amount of green light this leaf is reflecting, the surround will always reflect less, because it’s got lower efficiency. And whatever amount of red light it’s reflecting, the surround will always reflect more because it’s got a higher efficiency. Now, there is no physical law which says that these ratios should be taken. It’s the brain’s law – it’s the brain’s way of stabilising the world in terms of colour.

David: So that we can always say, ‘Oh, that’s a leaf because it’s green’?

SZ: Yes, you can identify something by its colour, absolutely.

David: So, in some ways, we’re not making reality up, but we are imposing a, sort of, slightly artificial order on it.

SZ: No, no, no, no you are making reality up, in a way. The only reality that you can experience is what the brain allows you to experience. Now supposing that you did not have this ratio-taking mechanism in the brain, what will happen? Sometimes that leaf would appear red, sometimes it would appear green, sometimes it would appear blue, sometimes yellow. Then you would no longer be able to recognise it by its colour because you’ve not stabilised the world.

David: Which would be bad news if you fed on green leaves!

SZ: This would be bad news if you fed on green leaves, indeed. It would be very bad news.

David: If you got to a certain time of day and say, ‘My God, there’s not a leaf in sight!’

SZ: Yes, yes, so I think that this is another fundamental issue, which is that there is a reality out there and that we represent that reality, and we take part in constructing that reality. Our brain, through its laws, takes part in constructing that reality. And here in comes stabilising the world: the brain is able to stabilise that world, and acquire knowledge about it, and that’s the only way it can do it.

David: When you talk about stabilising the world, what struck me was that the brain must get a certain pleasure from doing that, because it makes sense of it, as you were saying.

SZ: Yes, yes.

David: And in some way, what you’re doing in science, at a sort of cognitive level, is you’re doing that same thing. You’re saying, here’s all of the confusion of the world, and I will stabilise it by saying, well, underneath this, there are these stable rules that allow me to understand all of it.

SZ: All these mathematical formulations which tell you about the structure of the universe are also an attempt, at a highly cognitive level, to acquire knowledge about the world. I mean, it would be correct, would it not, to say that the description of the structure of the universe is an attempt to acquire knowledge about it.

Ard: Yeah, that’s right.

SZ: Now, there are situations in which there are contradictions. For example, you know, the well-known optical illusion: the bi-stable figures.

David: Oh, the young woman/old woman or the duck/rabbit

SZ: Yes, duck/rabbit, that sort of thing, which you can illustrate. Now, there is no solution to this… there is no certainty as to which solution is the valid one, because there isn’t a valid solution. So what the brain does is very simple, it makes both solutions valid, but only one has the conscious state at any given moment: you cannot see them both. And what does the brain do when you’ve got the laws of gravitation conflicting with the laws of quantum mechanics? It treats them separately. So, it’s again using the same strategy of saying, look, they are both correct, but not at the same time.

Ard: So something which is very surprising about the laws of mathematics is that somehow our brain has evolved in order to understand these laws, apparently, but then it turns out these laws are deeply engrained in the universe. So why did our brains…?

SZ: Well, our brains have evolved in the universe, and they… This is not an easy question to answer, and I just do not know the direct link between the structure of the universe and the structure of mathematical formulae which reveal that structure of the universe. But what is evident is that there is a certain logical deductive system, which by the way is applicable in as much in mathematics as it is in the humanities, and to obtain… to stabilise the world, to obtain the knowledge, you have to obey that logical deductive system.

Ard: Do you think that suggests that that logical system might somehow be in the universe before our brains arrived?

SZ: I wouldn’t dare stick my neck out as much as that. But I would say that it is through that logical system that you derive knowledge about the universe, and hence the reality you create, and the reality that you know, is based on that system, and because that system is similar in most humans, you get this similar, kind of, reality. Now, yes, there are big differences – a Buddhist maybe thinking of things in different terms — but if you look at it very carefully, it boils down to essentially the same thing.

I’m not saying there’s no physical reality out there. I’m not saying there isn’t a universe. I’m not saying the Earth isn't round. I’m not saying any of these things. All I’m saying is that to obtain knowledge about that, we do it through our brain, and we use our brains’ mathematical, logical system to obtain that knowledge.

Now, it would be, to me, extremely interesting about certain kinds of knowledge which are not directly observable, such as the Big Bang, such as black holes, such as the fact the universe was a billionth of the size of an atom before the Big Bang. These are not directly observable by us: these are deductions arrived at by mathematical formulations.

I’m very interested to learn, and I’ve got no strong position on that, if a totally different logical system would have arrived at the same conclusion. Now, if it does, then my argument is completely null and void, on the other hand, if it does not, then you’ve got to concede that a significant part of our knowledge is based on the structure and functioning of our brains.

David: So it’s whether the lens that we look through reflects what’s out there, or somehow distorts it? Whether we look through a glass darkly or clearly?

SZ: Yes, yes, yes.


David: Why did you get interested in beauty? Because it’s not the normal thing that neuroscientists get interested in.

SZ: Well, it’s part of a more general question, which is I’m interested in the visual brain: how the visual brain functions, how we see. So the next step, really, is to ask, how does a visual input arouse an emotional state? And one of these is beauty. In a sense, what is the point of learning all about the visual brain and not being able to say what happens in your brain when you experience something which is visually beautiful? So that was the inevitable next step.

David: And what were you expecting when you started? Were you expecting that beauty would be a separate thing?

SZ: No, I think in this instance we just did not have any hypothesis. We just thought that it would be interesting to see what happens when you experience something which is visually beautiful: not only beautiful portraits, beautiful landscapes, but also beautiful abstract art. And then you go and say, well, philosophers have spoken of beauty in the abstract, so I must look at musical beauty as well. And then you reach the ultimate question, which is mathematical beauty, because mathematical beauty is one of the reasons why mathematicians speak of mathematical beauty in poetic terms. One mathematician described one of the beautiful equations as the equivalent, the mathematical equivalent, of the soliloquy in Hamlet. So you see how impressed they are. And indeed, when we did the experiments on mathematics, some of the subjects were in tears.

David: Really?

SZ: Yes, yes.

David: So, wait a minute, tell me what you did in this experiment.

SZ: Well, all we did was to give them sixty equations to classify as to how they experienced them as beautiful. We gave them a scale from one to nine: one was very beautiful and nine was very ugly. And each one classified them according to their own subjective experience, and then they came into the scanner and looked at these same equations and reclassified them. So, we now knew that they had a category of equations which to them were beautiful, ones that were ugly, and ones that were indifferent. And the experience of mathematical beauty correlates with activity in the same part of the brain as experiencing musical beauty or visual beauty.

David: Can you show us?

SZ: This is part of the emotional brain. So this is a brain looked at in mid-section.

SZ: This is the front of the brain. This is the back of the brain. So you’ve bisected the brain, and you’re looking inside there, and this shows you the area of activity in the medial orbitofrontal cortex, which correlates with the experience of mathematical beauty.

David: So when your mathematicians said, ‘That’s beautiful’, that’s the bit that lit up?

SZ: Yes, yes, exactly. Not when they said it, when they experienced it was beautiful. Then if you look at the regions of the brain which are active with musical and visual beauty, now you’ve got the same area. You see this area in yellow is common to both. There’s a huge area of overlap, but it’s the same area of the brain that’s active when you experience mathematical beauty.

David: So what does that tell you, Semir?

SZ: Well it tells you a number of things. First of all, as a neurobiologist, let me just rephrase this question, ‘What does it tell me?’ You have to understand what am I looking for. I’m not looking to explain beauty or to tell you what art is, nothing like that. I am really trying to only find out, because I’m a scientist, what are the areas of the brain which are engaged when you experience beauty.

So the first thing that it tells me is that the experience of beauty, regardless of source, correlates with activity in a given part of the brain, number one. Number two, it is part of the emotional brain. Number three, that the activity there, I have not shown you this, but the intensity of activity is related to the intensity of the experience. In other words, if you find something extremely beautiful, then the intensity of the activity is much higher than if you’re indifferent to it or something.

But it also raises questions which inevitability make us trespass into other fields which do not properly belong to us, which is, what is the use of beauty? What does it indicate? And why is there a common area in the brain for the experience of beauty from such diverse sources?

And this question especially imposes itself in respect to mathematical beauty. What is it about mathematical beauty that people experience? Now, this part of the brain is also part of the reward centre of the brain and pleasure. But then, you see, beauty is never divorced from reward and pleasure: beauty is a rewarding experience, it’s a pleasurable experience, so the two are mixed. And if one was to read the philosophies of aesthetics, they are always talking of the three – of pleasure, reward and beauty – almost synonymously.

So the question I would ask is, what is it about mathematics that people find so beautiful? It’s a very difficult question, and the answer I would give is that they find something in the logical deductive system of mathematics that makes sense. It’s entirely based on the logical deductive system of the brain, and where did this logical deductive system develop? It developed in the universe.

So it’s an interesting question to consider: if you take a very sophisticated mathematical equation, for example, quantum mechanics, and you have an equation which does not make sense to the logic of the brain – the brain’s deductive logical system – will that ever be considered as beautiful? And if not, will it ever be considered as true?

What’s his name? Eh…

Ard: Dirac?

SZ: Paul Dirac, thank you. Dirac did say that the guide to the credibility and the truth of a mathematical equation lies, above all, in its beauty before its simplicity. If it is beautiful, then chances are higher that it will be true. But ‘beautiful’ implies that there is something in it that satisfies the brain. In the case of mathematics, I would say you’re satisfying the logical deductive system of the brain.

Ard: I have experience myself of studying physics, learning about the Dirac equation, and just being blown away by its beauty. And part of the reason was because Dirac took this theory of quantum mechanics, of small things, and special relativity of fast things, put them together for the electron, and out popped the positron. You know, that was anti-matter that was predicted by taking small things and fast things and putting them together. So he took two unrelated things, put them together and a third, completely unexpected, unanticipated, unimaginable thing happened, which was you predicted a new particle, which was anti-matter.

SZ: Now, there is another story of Hermann Weyl. Hermann Weyl and his attempt to reconcile the theory of relativity with James Clerk Maxwell’s electro-magnetism led to mathematical formulations which were rejected at the beginning. He accepted them only because they were beautiful. Einstein objected to them, and it was only after they were published – ten years after they were published or so – and the event of quantum mechanics, that people began to see that these were true. So the guide to the veracity of the equation was its beauty.

Ard: So that’s a really surprising thing.

SZ: Yes, indeed, extremely surprising.

David: It’s more than surprising, it’s just mysterious. Why should it be that way?

SZ: Well, I’m still surprised by it. You know, I’ve got the authority of people like Paul Dirac and Hermann Weyl and Michael Atiyah and others who speak about these things. It is shocking in a way that you find something… You said you were ‘blown over by it’. That’s a dramatic turn of phrase, but apparently it is true.

Now, in the same way, I think there are people who are extremely moved, and indeed are blown over, by the first sight of the Pietà of Michelangelo. It’s a very deep, emotional experience which is very difficult to recapture outside this frame of actually seeing it. So these are the sort of things which lead you to ask the question, what is the use of beauty? Darwin saw it as only a question of sexual selection, which of course it is, but that’s not the only thing. It’s doing a lot more.

David: But isn’t there something strange that the bit of the brain that says that bit of mathematics is beautiful is the same bit that says that this sculpture is beautiful. Why should that be?

SZ: I don’t think that bit of the brain says anything about this bit of mathematics is beautiful. I think all that happens is that when the Michelangelo Pietà, or the mathematical equation, satisfies something in the brain, then you experience beauty, and then you have activity that correlates with the experience of beauty. I don’t think there is an area which… It’s a question of satisfaction and pleasure and reward.


David: Was there some significance to you, beyond what you’ve said, of finding that it’s the same part of the brain that’s linked to the emotional brain that lights up for mathematical beauty and other kinds of beauty? Is that what people expected before? Is it what you expected?

SZ: No, no, no, no, no, no. I had no such expectation. There were any number of possibilities. There was the possibility that this part of the brain did not light up. There was the possibility that the regions of the brain which are critical during the working out of mathematical equations would be lighting up. It could be, perhaps, the audio-visual area is lighting up. So there were no expectations, but it just happened to be same area, which actually mildly surprised me because the experience of mathematical beauty is derived from a highly cognitive source, whereas visual beauty is a very elementary visual source.

And the other thing which had been a critical issue in the philosophy of aesthetics, is can aesthetic judgement ever be quantified? And the answer is yes, in the sense that when you declare something is more beautiful, and these are all declared in writings after the experience, then the activity there is higher than when you find something less beautiful.

So, in a sense, philosophers should be the last people to be upset by these things because they have always spoken about beauty in abstract terms. If you look at John Locke or Hume or any of these people, or Plato or Aristotle, they don’t talk about visual beauty or assimilable beauty, they talk of poetic beauty, beauty in drama, beauty in music, beauty in, in painting and so on.

David: So they’re saying that beauty of itself is a part of the universe. It’s an abstract thing but…

SZ: Well, I wouldn’t put it like that. I would say that activity in a given, specific part of the brain correlates with the experience of beauty. So, if you were to sit down and say to me, you know, ‘Look, I know that you’re only a neurobiologist, and I know I shouldn’t be addressing this question to you, but it’s late in the night. Let me ask you, what is beauty?’

So I would say to you, ‘Look, I can’t tell you what beauty is, but I can tell you a characteristic of beauty which every time you are going to experience it, you’re going to have your medial orbitofrontal cortex increase its activity.’

I’m not even going to say it’s because of something beautiful, but it correlates with it. So I can give you a definition of beauty. I can tell you that when you experience beauty in Hagia Sophia or in the windows of a church, in Mexican sculptures, or the paintings of Cézanne or Poussin, then I can predict for you that you will have activity in the medial orbitofrontal cortex while you experience beauty. So that, I think, is progress.

Ard: Yeah, it is progress, but all you’re saying is it correlates. Beauty is infinitely more than the bit of my brain lighting up.

SZ: It is infinitely more. It’s infinitely more than the beauty of your brain lighting up. It’s infinitely more than a particular part of your brain lighting up. But I don’t think you can experience beauty unless you have a brain. At least I am convinced of that. And, given that, I don’t think you can have a complete theory of aesthetics without taking into account the way the brain handles such experiences.

Now, these are shocking words to many people, but it doesn’t matter. I think many people would say it’s got nothing to do with the brain, beauty exists outside. I’m happy with that statement. I don’t necessarily agree with it, but I would not care to spend time challenging it.

But what I’m saying to you is if you want to have a complete theory of aesthetics, then you must take into account the organ which is responsible for experiencing something that’s beautiful.

Ard: What you’re saying is not that this is the whole of beauty in the brain, this bit lighting up?

SZ: Now this is an important issue you’re raising. These are the usual criticisms directed at us: ‘You are a reductionist, and you are this and you are that. You’ve discovered the pleasure centre; you’ve discovered love centre’. All of this is not true.

David: Or the God Spot, that’s a favourite one.

SZ: Yes, the God Spot. And all of this – the ‘Moral Molecule’ – is not true. I mean, all you’re saying is there is one area of the brain which is especially active when you experience something. You do not say if you cut that bit out and put it in a Petri dish that you would experience beauty. So you’re not saying that it works on its own. But I think that science cannot proceed without reductionism. It’s out of the question. I mean, you cannot ask, what is the structure of this table? You’ve got to ask about the molecules, the subatomic particles.

David: But it’s not the whole story, is it?

SZ: Of course it’s not the whole story. But in order to proceed, one has to do a bit of reductionism. I mean, I find this a very, very trite and silly sort of stone to throw at you, and in a way, it shows a bankruptcy of ideas. You don’t know what else to throw so you throw that.

Ard: But you can imagine the kind of emotional sense somebody has. They see this and they think Professor Zeki has taken beauty and broken it apart and put it into the brain.

SZ: Yes, well, look, Professor Zeki hasn’t done anything of the sort. What Professor Zeki has done is to say to you, ‘Look, you are experiencing beauty and it’s interesting to me to know what happens in your brain when you experience beauty.’ He’s not trying to explain beauty: he’s just trying to understand the brain, which is a different thing. But people, for reasons I do not understand, are afraid of anything that probes into more complex human characteristics.

I think that there is a fear, which I can’t explain, in any attempt to try and explain things like the experience of beauty, or the experience of desire, or the experience of love. I don’t know why people fear this. They think it is too reductionist. They think you are always trying to explain a very complex phenomenon, and they put words into our mouths which are not there. I mean, nobody, no scientist I know, said that they’ve seen the love centre in the brain, or the beauty centre, or anything like that. 

25:14 - THE amoral BRAIN

David: What about the good? People sometimes feel that the good is also beautiful: that good things are beautiful and bad things tend to be ugly. Is there a…?

SZ: It is important to emphasise, I think we left out of the discussion a finding which is important, that moral beauty also correlates with activity in the medial orbitofrontal cortex.

David: Does it? Really?

SZ: This is not our finding, it’s a finding from somebody in Japan. But in the sense of moral beauty, what I mean…

David: It lights up that same bit as mathematical beauty and…?

SZ: Yes, yes, yes.

Ard: But what is moral beauty?

SZ: Well, for example, if I put you in a situation where you’re very hungry and I can give you a very, very nice-looking steak, but you can give up that steak, and remain hungry, and give it to a child who is poor and hungry, then in the first case you have satisfied yourself. You had your reward and pleasure. In the second case, you have satisfied your moral sense, and in such conditions the activity in the medial orbitofrontal cortex goes up. Sorry, I should have said that before. So there is a connection in terms of brain activity in terms of moral beauty, and visual beauty, and musical beauty, and mathematical beauty.

Ard: That’s fascinating.

SZ:-And the experience of someone beautiful as being somebody morally good probably reflects that.

Ard: So we get fooled sometimes by our brains, looking at somebody beautiful and thinking…?

SZ: You get fooled, that’s right.

Ard: But on the other hand, you get fooled because there is something to it. A true moral act, like sharing your food when you’re hungry, actually lights up the same part of the brain.

SZ: Yes, yes, yes, yes, yes.

Ard: So, I’ve seen you write that the fact that we exploit people is part of our neurobiology.

SZ: Yes, yes, yes.

Ard: Would you say that’s true?

SZ: Well, you see, I think in terms of that, I’ve got great difficulty in terms of discussing these issues with people who have got no interest in neurobiology, because they think that hate is evil – it’s bad – and love is good. I don’t think that’s the way it works. I think hate and love are part of the makeup of the brain. Hate and love have both served their function in achieving great things, and also in destroying great things. So, to me, it is an amoral system. It’s not a moral or immoral system, it’s an amoral system.

Ard: Our brains, you mean? Our neurobiology?

SZ: Yes, our neurobiology. I don’t think a neurobiologist would have said, ‘Look, I must have a brain that loves. I must have a brain that hates.’ I think it’s just, ‘I must have a brain that survives, and I must have a brain that achieves.’

David: Well, love and hatred a bit like light and dark. You can’t have the one without the other?

SZ: Yes, they are.

David: No matter how lovely the light might be, if there was no dark, you wouldn’t see the light.

SZ: Yes, it’s part of our repertoire.

Ard: But I think what you’re saying is that these neurobiological states are neither good nor evil, in and of themselves.

SZ: Yes.

Ard: The category of good and evil is something outside of those neurobiological states. It’s a different category.

SZ: Yes, I mean, I would say that good and evil, and the urge to destroy, and the urge to love, and the urge to compassion, all have strong survival values.

Ard: But that doesn’t make them right or wrong?

SZ: In terms of neurobiology, it doesn’t make them right or wrong. It’s just these are states, and this…

Ard: But just in terms of us as human beings, right or wrong is a different category?

SZ: I don’t know. I mean, what is right and what’s wrong? I think the killing of millions of people throughout the ages has been tolerated and accepted, and indeed welcomed, rapturously. So, at that time, presumably people did not think of it as wrong.

Ard: Would you say that they were mistaken?

SZ: Well, who am I to say whether they were mistaken or not? At the time they did it, they did it without qualms.

Ard: Yeah, that’s true.

SZ: Equally, people have shown great compassion and sometimes have not asked themselves whether showing great compassion was necessarily a good thing, but they’ve done it. So I think that these are biological things. I’m not sure that they are written out there.

David: When I heard you talking about the brain trying to stabilise reality, like keep the leaf green, what jumped to mind was this tendency that people want to say that there are moral absolutes, moral reality – this is always good and that’s always bad – and I just wondered whether it’s ridiculous to wonder if that tendency derives from that strategy the brain has of trying to just keep things stable.

SZ: I think so, and there’s another similarity there such as you find with illusions, such as you find with the contradiction between the laws of gravity and the laws quantum mechanics. You accept them both; you accept they’re both valid in their own right: they don’t clash. So you would classify some people as good, some people as bad, some people as moral, some as immoral. You stabilise the world for yourself in this way. It’s a very easy pigeon-holing classification.

David: So it might not be that you can say this is morally, absolutely good and this is morally bad, but that whole drive to make a moral world in some ways looks, to me, like it leaps off from that very ancient thing that the brain does. It wants to say, ‘I must be able to categorise things as good or bad.’

SZ: Yes. Yes, yes, yes, yes, yes, absolutely. I think it’s part of the imperative working of the brain to stabilise things or to categorise things, and if they come into conflict, you just put them into separate categories.

Ard: I think that the point is that you stabilise the colour green because that makes it much easier for you to understand what’s really there. So it may be that you stabilise…

David: …morals because they’re really there. You have an answer for everything.

Ard: No, no, no, no, not because it helps you. Even though it may not always be perfect, it helps you see more clearly what’s really there. It has a use. It has a…

SZ: But another word for stabilising would be categorising…

David: And making sense of.


Ard: What is the sublime?

SZ: Give me a second and I’ll tell you. What is the sublime? The definition of it is as interesting as anything else about it: beauty from horror; awe mixed with horror. Or pleasure from displeasure, which is Kant’s definition. It is something which philosophers have considered to be entirely a construct of the mind. So you get Emmanuel Kant saying that to be able to think of infinity as a whole surpasses any standard of sense.

I mean, you cannot sense infinity, you’ve got to think about it. And during the English Enlightenment, in the 18th century, it became, sort of, the awe and the horror, and the beauty of it was seen in natural landscapes: Mont Blanc and Everest and these sea storms, and things like that.

So these were things that you could, sort of, contemplate. They were awesome and therefore beautiful, but they were also things which were terrifying. However, it’s different from the terror that you might feel if somebody were to come at you with a knife.

I was, however, expecting to see some activation in the medial orbitofrontal cortex here, with the experience of the sublime.

David: So it would be beautiful?

SZ: Yes. These experiments were very similar to the experiments on beauty, except that people looked at Mont Blanc and Everest and Mount Fuji and stuff like that.

David: Right.

SZ: And then the pattern of activity was slightly different. There was no activity here.

David: So on that picture, where was the beauty part that lit up previously?

SZ: It would be here.

David: Right. So it didn’t light up at all?

SZ: It didn’t light up at all.

David: Was that a surprise?

SZ: Yes, this was a bit of a surprise to me. I was expecting to see some activity there, but apparently not. And, in a way, the language begins to make sense, because the definition of sublimity is distinct from the definition of beauty. You see, beauty is, as Edmund Burke said: it’s small; it’s comprehensible; it’s assimilable. The Sublime is vast, it’s awesome, and it makes you feel small. It’s a very, very different experience. And they emphasise, and philosophers did, it was more a construction of the mind.

With the experience of the sublime you’ve got another system that’s active when you see something beautiful. But the big difference between the two is that there is no activity in the medial orbitofrontal cortex.

David: The philosophers and the art historians will talk about the sublime and say it’s awesome and it invokes terror and it’s all very flowery, and you are tempted to think they are just making it up because they’re very clever chaps who have a lot of time on their hands.

SZ: No, no, no. I think they are not making it up. I think they are being very serious and we take them very seriously, and in fact, they are right. First of all, and this is not evident, they are really impressive in dividing sublimity from beauty. It’s a very interesting conceptual subdivision which not everybody would have made.

And secondly, this distinction finds a difference in terms of brain activity. And thirdly, yes, you’re right, there are parts of the brain which are active when fear, or at least dangerous situations are there.

David: Right.

SZ: So this is the area here which is active during the experience of beauty and shown in green. You can see there’s no red there, which means it was not active during the experience of the sublime. The experience of the sublime led to activity here which actually refers to the nucleus inside the brain. For example, this region here, the inferior medial frontal gyrus has been strongly implicated in emotional experiences, and the experience of the sublime is an emotional experience. So it is there. You’ve got also areas which are deactivated, which are not visible on this but will be visible on this.

David: So they’re supressed, you mean?

SZ: Yes, activity in them is supressed. For example, the superior frontal gyrus and then the singlet area which is here, alright?

David: And what does that say?

SZ: Well, these are areas which have been implicated in self-awareness, and they are referential with a respect to yourself, with respect to the outside world.

David: Ah, right.

SZ: Not by us, but by other people. And, and in a sense, it is interesting that they’ve been deactive. You’d get rather lost in this enormity of the experience.

David: So when you’re experiencing the sublime, the bit of your brain that says, this is me in the world, gets supressed?

SZ: I’m not sure it gets suppressed. I mean, it’s interesting that there’s deactivation in an area which is involved in a self-referential part of your brain and your position in the world. So you feel, I suppose, slightly diminished.

David: Which is, of course, exactly what people say when they talk about the sublime.

SZ: Yes, yes, yes.

David: So the map of activation and deactivation you see does actually correlate with how all these philosophers have been describing the experience.

SZ: Yes, and, I think one of the reasons why we went into the study of the sublime is because it is described, as in Kant, as an experience which transcends the standard of sense. And when you have infinity – infinity is sublime and it’s indescribable in sensory terms, in cognitive terms. So, as I say, there’s nothing here that can contradict anything the philosophers have said.