Marcelo Gleiser FULL Interview Transcript


David: Can you please tell us just what the fine-tuning argument and problem has been in physics.

MG: Right, so fine-tuning: imagine the old radios that you had to tune in to the station, and if you didn’t quite get it right, you wouldn’t hear the music. So fine-tuning is somewhat like that. Imagine that the way we understand nature is through this alphabet: the alphabet of constants – the constants that physicists like to call the Constants of Nature. So you have the electron mass, the electron charge, the proton mass, the proton charge. There are quite a few of those, and the point is this: those constants have been measured through the ages to have certain values which are very specific, and had they been otherwise, meaning if those values were different, nature would have worked in a very different way than it does. And if nature worked in a very different way than it does, we wouldn’t be here.

So the fine tuning essentially means that the Constants of Nature have the value that they do have and because of that we are possible. So the question becomes, why those values?

MG: If they were different, we wouldn’t be here.

Ard: So why would we not be here? Would there be no life?

MG: If you tweak just a little bit of the proton mass, stars would not be possible. If you tweak the proton mass, if you tweak the neutron mass just a tiny bit – less than a percent – stars would behave differently. They would burn much faster. They would not produce the heavier elements – like calcium, iron – that we need.

Ard: So what would happen if the stars were different?

MG: Without fine-tuning, the stars would not behave the way they do. They would not produce the chemical elements that they do, and life as we know it, which depends on a whole set of different chemical elements, would not be possible.

So when people jokingly say, ‘We’re all stardust’, it’s not a joke. It is actually beautiful. It’s true: we definitely are stardust, and, in fact, all the chemical elements that we have in our bodies – the calcium in your bones, the iron in your blood – they belonged to stars, billions of years ago before the solar system existed.

David: So what have been the responses to that problem over the last 30 years?

MG: So one of the responses is, who cares? You know, it just happened to be that way. It’s an accident, and the fact that it’s an accident doesn’t make it special at all. So that’s one possibility: it’s all random, and because of that there is no reason to try to explain it, which is quite appealing, actually, in many ways.

The other one is to say there is a reason for this: everything has a reason, and the goal of science is to explain why things are the way they are. Hence, the fact that the electron has this mass etc. must have a causal explanation. And so what would that be? Then it becomes not so much a fine-tuning, but a search for an explanation for the fine-tuning.

David: Right.

MG: There have been a few out there, but the most popular one nowadays comes from something called String Theory, which is a very bold attempt to understand nature in a completely different way than we usually understand, which is that instead of things being made of little bits called elementary particles, they are actually made of vibrating wiggly things called strings. And the same way that when you play a violin or a guitar you pluck a string, and if you change where your finger is, you’re going to get a different sound, a different frequency or vibration, those strings can vibrate in different ways, and depending how they vibrate, they actually emulate the properties of all the different particles of nature. So it’s a very cool idea, and it’s an idea that, in principle, could bring together all different forces of nature: so the big, grand unifying theory.

The problem is, on these string theories, that you would hope, originally, when they were proposed in the, early 80s – they were called Super Strings – they would say, ‘We’re going to solve these equations, and the solution is going to be the universe as we know it!’ You know, everything is in there. And, people tried and tried and tried.

Ard: Did you try?

MG: I tried, yes. And one of the problems with these theories is that you have ten dimensions: nine spatial and one time. And then you look around, you’re like, ‘Wait a second, I only see three.’ You know, is it north, south, east, west, up, down? Right, three? Where are the other six?

David: So the other dimensions are here, they’re just curled up really small and we can’t see them?

MG: That’s right. They’re really so small that you cannot see them.

David: So they’re all around us?

MG: Imagine each point of space has a little six-dimensional blob, or sphere, associated with it, and that’s what it is. And it’s not so crazy because if you look at this. [Holds up a stick] This is a stick. If you look at it from very, very far away, it’s going to look like a line, and a line is a one-dimensional thing. You can only go this way or that way. But you look closer and you realise it’s not really a line because you can also go around. So this is more like a cylinder. But from far away it looks like it has one dimension, because this circular dimension around it is too tiny compared to the length of the stick.

The idea is exactly the same. Every point in space has this six-dimensional sphere hidden in it, and it’s just so tiny, we don’t see it. And so the question is, why are they so tiny?

So, back to strings. Strings, to exist, have to vibrate in this nine-dimensional space, and the point is those extra six dimensions, they can be folded up in many different ways – just like if you get a balloon you can twist it, you can make holes in it. These are different topologies. So the six-dimensional extra space has different topologies. When people start to calculate how many of these could be around, instead of ‘the universe’ coming out, they came up with a ridiculously huge number, which is a ten with 500 zeros on top: so, one with 500 zeros afterwards.

David: Isn’t that many more particles than we have in the universe?

MG: Oh, pfft! Yeah, many, many, many, many more particles.

David: That’s a big number.

MG: It is a ridiculous number, which means, now what? So the goal, the dream, of finding ‘the universe’ became, ‘What do we do with all this stuff?’ That’s where the multiverse came up. So each solution, each folding of this extra-dimensional space, is, potentially, a different kind of universe.

David: So we’re going to have 10 to the power 500 different universes to explain this one?

MG: Yes, exactly.

David: But instead of having the difficulty of explaining how one universe comes into being, now we’ve got to explain how 10 to the 500 universes came into being.

MG: Right.

David: And since we can’t explain this one, it seems to me we’ve just made the problem a whole lot worse, not better!

Ard: Yeah, but I think the argument would be that now you’ve got a mathematical theory, at least, a beautiful theory which explains that.

David: I don't know. It doesn’t seem that beautiful to me. We used to have the one universe we needed to explain, now we’ve got loads.

MG: Exactly. It’s like the universe now becomes a data point in a vast manifold of possible points, and are you really explaining something with that? Did you gain any knowledge from this?

Ard: And there’s a question maybe about can you do experiments on…?

MG: That, to me, is the fundamental question. Physics is supposed to be an empirically validated science. You come up with some hypothesis, doesn’t matter how crazy it is, but it has to be empirically tested. You’ve got to make an experiment, an observation, and say, ‘Yeah it’s okay’, or ‘It’s not okay’. In practice, it’s not so black and white. There are many, many subtleties to this argument, but at the end of the day you need to be able to prove your idea, otherwise it’s not physics, it’s something else.

Ard: Prove it by experiments.

MG: You prove it by experiments, and that’s why there is the rift, right? Because… It’s something else because it’s a different way of doing science. Because what you’re trying to do now is you’re bringing up an idea that is based on a-posteriori reasoning, which is, ‘We’re here’. We start from that, and usually the explanation is, ‘How did we get here?’ You go from beginning to end. Now, it’s starting from the end and you want to create an argument based on our existence. And the point is, is that good enough as an explanatory tool, or are we just throwing in the towel and pretending we are smart?

Ard: So wouldn’t you also say that this method of trying to find out about other universes is like the method Dirac used to predict antimatter? He used the tools of mathematics: he tried to make something consistent and out of it pops antimatter. You do it again and you get the Higgs boson. You do it again, and out pops other universes. Isn’t that…?

MG: Yeah. That would be beautiful if I could go and do an experiment to see the multiverse the same way I see the Higgs or the positron, but I can’t. So it…

Ard: That’s where it’s different?

MG: Yeah, so the mathematics is compelling. But being compelling doesn’t mean it’s right. And that’s very important.

Ard: Do you think that because, in the past, that compelling mathematics has turned out to be true, that physicists feel that it must be true about the multiverse?

MG: Well, you have to be careful. It has been true a few times, sometimes, not always.

Ard: Okay.

MG: And of course, when it is true, it’s so mind-bogglingly spectacular that you go, ‘Whoa! There is something going on here.’ But you can’t make that into a rule.



David: You are not one of those who think that mathematics is woven into the fabric of the universe?

MG: So, the question of mathematics being the language of God, so to speak, or, sort of, the blueprint of reality, right? There is no question that there are patterns in nature. They are repetitive and they can be described through mathematics in beautiful ways.

You have not just symmetric patterns, or almost symmetric patterns – I like to make that distinction because nothing in nature is perfect. You have periodicity in the orbit of planets, and things like that. Clearly there is order, but I think to just say that this sort of symmetry in nature is the hidden code, so to speak – that all you have to look for is that symmetry – is missing half of the story.

David: What’s the other half?

MG: The other half is the role of asymmetry in nature. There is a lot of imbalance in nature, and it’s really through the complementary roles of symmetry and asymmetry that nature creates. A lot of stuff happens because of this imbalance between the two.

Ard: Give an example.

MG: I have lots of examples. One good example is in life. It turns out that proteins, which are made of chains of amino acids, like big molecules, and these amino acids they are basically molecules and they have a carbon in the centre, and then they have four sticks coming out of it. And it turns out that they come in two ways. They can be what we call left-handed and right-handed, jby the way in space they look like. And it turns out that if you go and you synthesise an amino acid in the laboratory – it was Pasteur that discovered this – you get 50/50: fifty percent with the left-handed shape and 50 percent with the right-handed shape. When you look at the amino acids in all living creatures, from bacteria to a sequoia, they all come only in the left-handed shape.

Ard: So, why…?

MG: The right-handed shape just is not there. So there is a fundamental asymmetry between the two, and without that asymmetry, the lock-and-key mechanism that proteins need to, kind of, fold and split and create, be part of reproduction, etc., wouldn’t work.

David: Hm!

MG: And we do not know why this is true, okay? We just know it’s true. It’s there. It’s fundamental for life. So that’s an asymmetry which is very important, for example.

Ard: How about matter and antimatter?

MG: Exactly, so there you go. You know, that’s the good physics example: the fact that Dirac’s equation predicts that there should be as much matter as antimatter in the universe. And antimatter is nothing so esoteric that goes up instead of down, or anything like that. It just means a particle that has an opposite electric charge but the same mass. So, for example, the electron, which is negatively charged, has an antimatter particle called the positron, which is positively charged.

In principle, they should come in equal amounts, but when you look out, you find out that there is no antimatter out there – very, very, very little. And that’s good because if there were as much matter as antimatter in the universe, we wouldn’t be here.

David: We’d have all gone, pfft!?

MG: Exactly, because matter and antimatter, when they come together, they disintegrate into a puff of gamma rays – very high-energy radiation. So if you find your anti-person walking around, don’t shake hands. And so that’s the story, and we do not know. I spent a long time trying to understand what sort of causal processes may have happened early in the history of the universe that would have biased one form over the other, and there are all sorts of ideas – none of them is very compelling right now.

Ard: Okay. That’s a big mystery.

MG: So you need both. And I think it’s this yin and yang kind of thing, you know? You can’t just look at this reverential perfection, symmetry, as, kind of, the language of God, where nature is showing you that you really need both to make sense of things.

Ard: But there is some beauty to this combination between symmetry and broken symmetry.

MG: I think so. I have been proposing that there is what I call the aesthetic of the imperfect.

Ard: Okay.

MG: Physics is a little old-fashioned, in a way, in thinking that it’s really the perfection that counts. It’s truth, right? The arts and music, they moved away from that in the early 20th century, and I think we’re still stuck in it.

Of course, symmetry’s fundamental: you cannot be a serious scientist, and physicist in particular, without having deep respect and veneration for symmetry. But symmetry is often an approximation to the real thing.

There’s this joke about the physicist that looks at a cow, and he says, ‘Consider a spherical cow as the first order approximation to what a cow is.’ And it works quite well for many things, right? If you want to collide cows at high speed, it’s a good approximation. But it’s not a good approximation if you want to milk the cows and things like that.

Ard: So do you think that when we understand biology better, that this aesthetic of symmetry won’t be the right way of thinking about it?

MG: Yes. I think life is a great example of the importance of asymmetry. You know, I have another example, which is Marilyn Monroe. So, Marilyn Monroe had a beautiful little mole. Imagine if she had two equidistant moles, how ugly she would look. So symmetry is not always beautiful. There is this breaking of symmetry, and I think we should embrace a combination of both.



David: Why do they want this Grand Unified Theory?

MG: I think it has a little bit to do with Occam’s razor: the idea that you want to look for the simplest explanation for everything, if possible. And if you look at nature, nature is complex: it’s very diversified. But perhaps we’re looking at nature with the wrong glasses. If you put the right glasses on, you would see that all that we see as different is really a manifestation of this single force, and so that’s Grand Unification.

David: Sounds awfully religious to me.

MG: It does, doesn’t it? Sounds like monotheism.

David: Yeah. Sounds like God in a white coat.

MG: That’s exactly what I think. I think that even though I’ve worshipped unification for many, many years in my career, I’m not like that anymore – I’ve sort of moved away.

David: Why not? What happened?

MG: Because I don’t see the point.

David: Wait a minute… What happened to you that you used to see the point, and then now you don’t? That’s a bit of a change.

MG: Yeah. So, what happened to me was that I was a full-fledged Platonist before that: I really believed in symmetry as beauty and beauty as truth.

Ard: Sure.

MG: And so what could be more beautiful and true than to have an all-encompassing theory of nature, where all different forces are really a manifestation of a single force. And you would say, everything came from the Big Bang; everything was one in the beginning, so there must have been a single force explaining all of that. It’s very compelling. I mean, we’ve had 3,000 years of monotheistic thinking, and so we are kind of biased to look for one explanation – these absolute explanations.

My whole career as a scientist has been within the expectation of unification, because I was young in the 70s, but I was doing my PhD in the 80s, and through this whole time we were, like, ‘Okay, come on, come on!’ and ‘Where is it?’

Ard: Soon it will come.

MG: Yeah, soon it will come. It’s next year. And what we’ve been seeing is it has not. So you have two choices here: one is it doesn’t matter that it’s not coming, because it’s there, and it’s just a matter of time before we find it. Faith – you know, there is faith in science, obviously. And the other one is let’s listen to nature. It’s trying to tell us something, and let’s pick it up. And what are the consequences of that?

So I came up with a solution to this dilemma which is the following – at least I’m happy with it; I don't know if everybody else is, but I’m happy with it – it’s that the most that we can expect to achieve as humans, in terms of understanding nature, is a simplified theory that could encompass everything as we know it now.

So it might be possible to have a unified theory of what we know now, but it is a fundamental mistake to call that theory a Final Theory of Everything because that goes completely against the spirit of science.

You know, science moves through a progression of ideas. We invent new tools, we find new things, and so who is to tell that we get this theory, ten years from now, the beautiful theory of everything, and then 150 years from now this new machine finds another force of nature? ‘Oops! That’s not part of our scheme. Now what do we do?’

So you have to encompass that. And there is no fundamental reason why knowledge should be final. Because the way we acquire information from nature is through experiments, through tools, and every tool has a limit. You can see that far, you can probe that small, but there is a limit to how far we can see.

Ard: So are you saying that maybe nature’s like an onion. You keep unravelling one bit and then there’s another bit beneath it and another one beneath it, and we shouldn’t ever say that we’ve gotten to the end?

MG: Right. I like to say that knowledge is like an island.

Ard: Oka, like an island? Okay.

MG: Yeah, knowledge is like an island. What we know of the world fits in an island. This island moves out, and sometimes it goes back in when we retreat. We say, ‘Oh, we understood that. No, no, we don’t understand that.’ So we go back. But as any good island, it’s surrounded by what I call the ocean of the unknown.

As this island of knowledge grows, so do the shores of our ignorance, because the perimeter of the island, which is the exposure to what we don’t know, grows as well. Because as you discover more about nature, you become equipped to ask questions you couldn’t even have anticipated before.

There is always going to be other things to find out, which I find… Some people think, ‘Oh, that’s so depressing. What’s the point?’

And to me that’s exactly the opposite. The point is there is always going to be something to find out. That’s exciting, you know. That is like we are always going to be able to be in awe and confused and trying to figure things out.

David: I like that, because one of the things that worried me listening to Frank and others is… I got this feeling that what they wanted was to get their Theory of Everything, where they’d have… We talked about a T-shirt – we’d have all the rules on it and that would be it. From that, everything in the universe would fall out. And I got the feeling that it meant that as we got closer to knowing this Theory of Everything that the universe just got quite boring.

It would just become a machine where I understood it all, and it would just be a glorified watch.

MG: Yeah, absolutely. I’m completely like that. I think it would be a sad day, the day that humanity declared it understood everything about the world. A sad day, because without the mystery we wouldn’t create any more, and that, to me, is just an awful thing.

The dream that we can figure everything out at a very fundamental level, to me, is just a fallacy. I think that just does not make sense. It doesn’t make sense from a philosophical perspective either because it’s based on an absolute, which is there is the possibility of knowing everything exists. And having an absolute is sort of like you can’t contrast that with anything else. You say, ‘the Theory of Everything is this,’ and then you say, ‘Well, how do you know it?’

‘Well, because we know all there is to know.’ And that is wrong: we do not know all there is to know, and we cannot know all there is to know. And to me that opens up this whole freedom of the surprises that come from the unknown.

David: Do you buy into the notion that some people… We’re going to talk to George Ellis about emergence, and I hinted at it there, that when the universe began, presumably there were the rules of physics, but there was no rule of natural selection. It just wasn’t here, but now it is, which seems to me that if you’ve been really quick, if you’d been a physicist around at the beginning and you worked really quickly, you could have understood all the rules of the universe, then life would have come along, and you wouldn’t know everything, because the universe had made itself up a bit. It was now more than it was and had an extra rule. Surely, if it can do it once, who are we to say it’s not going to do it again?

MG: Absolutely.

David: So this notion that we could find all the rules and that would be it seems to me you’ve found all the rules up to now.

MG: I think that’s exactly right.

David: Or is that just rubbish?

MG: No, that’s perfect. And I would say you can divide the history of the universe into four ages: the Physical Age, which is from the Big Bang to the first stars – up to that point, there was no chemistry. And then you call it the Chemical Age, which is when the first stars burn and create the periodic table of elements.

David: So that’s something new already.

MG: That’s something completely new. Then you have the Biological Age, which is when some of these chemicals self-organised to create life. And then after the Biological Age there was the Cognitive Age, which is when some of these living creatures became so sophisticated that they were able to ask questions such as the ones we’ve been talking about.

So these are the four ages, and we don’t know if that’s all there is to know. And they all have different laws. There is no way out, you know. There are fundamental limits to how we can understand what’s going on. It doesn’t matter how sophisticated you are, you still have to follow the laws of thermodynamics. There’s only so much information you can process. There’s always going to be noise in your system, and so there is always going to be some loss of information. And so ultimate knowledge, to me, is just another name for God.

Ard: Okay. And so you think these people, even though they are often arguing against God, are actually doing it in a kind of religious way? They’ve got a new kind of god, which is the god which will explain everything.

MG: Yes, they are trying to make human knowledge into the new God.

Ard: Okay.

MG: And, of course, that horrifies a lot of people, because humans are not supposed to be gods. We mess everything up. And so we should understand our limitations and go back to being humble about how we think about creation and about who we are, before we jump into this incredible notion that we can know everything.



David: You’ve mentioned being… You said you were a Platonist. What do you mean? Tell us about Plato’s Cave.

MG: Plato’s Cave is wonderful. He talks about this allegory of the cave. The first point of his cave idea was that we live in an illusion, and that we have no idea what true reality is. In effect, the senses are always telling you lies. And the way he illustrated that was to say, imagine that you have a group of slaves. They’ve been chained since birth to only look forward to a wall in a cave. So you have all these slaves. All they do is look forward to that cave. Now, they don’t know this, but behind them there is this big fire. And there are some people that hold up little figurines and little shapes to project shadows onto that wall. And the slaves look at those shadows and to them that is the world, their world, because all they can see is whatever is projected on that wall.

So the shadows on the wall are their reality, which basically means that we also are looking at some sort of fake reality, because our senses can betray our reason – that the only way you can really understand things is if you move away from the senses and you go into the realm of mind. So, to Plato, if you want to find truth, you don’t trust your senses, you trust your reason.

Ard: Because out there, the real thing, the true Platonic real thing, is out there, and what we see is just the shadow of it.

MG: Right.

Ard: So if you have a triangle, we see the shadow of the true Platonic perfect triangle?

MG: Exactly. And so those objects of perfection, which are all mathematical objects of perfection – he called them the Perfect Forms – they only exist in your mind. And the true philosopher is the one that can understand those perfect forms and their mathematical beauty and purity, so that he or she can figure out how his God, which is the Demiurge, designed the world.



David: So how come you described yourself once as a Platonist? What does that mean?

MG: The notion of being a Platonist, and the fact that even Plato wasn’t as much a Platonist as the ones who followed him, this whole idea of Platonism simply means that there is truth in mathematics. That nature is mathematical. That if you want to understand the hidden code of nature, you have to do it through mathematics, and only through mathematics.

David: And did you used to believe that? Was that your philosophy?

MG: Yes, because it’s a very compelling idea. Because when you say 2+2=4, there’s some finality to that statement. You can hold that and say, ‘I know that,’ and that gives you a sense of safety, of security.

So you don’t want flakiness when you’re trying to pursue the quest of understanding everything. You want the most profound kind of truth that you can find. So if math can give you that, you embrace it with all your might.

David: And Ard has, I think!

Ard: Yeah…

MG: And lots of mathematicians and lots of physicists believe that. They believe that the fundamental core of nature is essentially pure mathematics.

David: And you’re saying you’ve moved away from that?

Ard: You don’t believe it anymore?

MG: No, I don’t believe that anymore. I think that mathematics is a human invention.

Ard: Oh!

MG: It’s a product of how we evolved in this very specific planet to make sense of things and to survive. So there are certain things in mathematics which are definitely true. So if you’re an intelligence that can count, you know, one, two, three, four, then you can develop the sense of a set of integer numbers, and from there you can go on and do other things. But there may be intelligences that do not count.

There’s this famous mathematician from England called Michael Atiyah who had this image of this intelligent blob that lived at the bottom of the ocean. It was dark. It didn’t move. It didn’t have to collect any food. The food just came to it from above, and all it sensed was the flow of currents. So this intelligence created a super-sophisticated hydrodynamics – the physics of fluids and how they move about – but it would not count because there was nothing to count, unless it could hear its own heart beat or something like that.

So the fact that you’re intelligent does not mean that you have to create the integers. It really depends on the context in which you evolved.

Ard: Would you say that’s a lack that it had?

David: I’m not convinced by that, because surely the prime numbers would still be prime, even though this creature hadn’t discovered…

MG: What if there are no primes? There are no numbers?

Ard: If you don’t experience numbers, you may or may not be able to count with them, but that doesn’t mean that they don’t exist.

MG: It exists to whom? I mean to that blob? It exists, and that’s all that matters, and it would know a lot about plasticity and shapes and the form of shapes, continuous…

David: That’s quite radical, isn’t it?

Ard: My dog doesn’t know about prime numbers, but that doesn’t mean they don’t exist.

MG: Right.

Ard: It’s because it lacks the intelligence, or maybe the experience of them.

MG: Where do they exist?

Ard: Who knows?

David: I asked this question and they laughed at me.

Ard: I think they’re non-empirical realities, but what’s wrong with that?

David: What’s a non-empirical reality?

Ard: Something you don’t need to measure in order to know that it’s true.

Ard: For example, in physics, Sir Roger Penrose gave us the idea of complex numbers, or imaginary numbers.

MG: Mm-hm.

Ard: So it’s very strange…  it surely looks like an invented thing – the square root of minus one – but it turns out that it had all this surprising richness to it that eventually allowed us to formulate quantum mechanics in that language. So, the argument is that you have something that seems very abstract and made up, but then it turns out to have a life of its own, and not only does it have a life of its own, but it ends up being able to describe things about the physical world that you didn’t know about when you came up with it. That’s very surprising.

MG: It’s surprising to a certain extent.

Ard: Okay.

MG: Because physicists are really good at picking the bits of mathematics that are useful.

Ard: Sure.

MG: There are all sorts of mathematics that are completely useless. To physics, they’re not picked. So I wouldn’t jump to conclusions like that, because, I think, at the very bottom of this question is the following question: what comes before, mind or reality?

Ard: What does that mean? Mind or reality?

MG: So the people that say that mathematics is the language, is the code of nature, they’re basically saying that there is mind before everything else. There is sort of almost like some sort of metaphysical plan to reality, which is that mathematics is the fundamental blueprint of everything that exists, and we’re just discovering that stuff because it’s just there. We’re just plucking the fruit.

David: A lot of mathematicians we’ve talked to have said that.

MG: Yeah, the pure mathematicians.

David: ‘We’re not making this up. We are discovering it.’ And you don’t think that?

Ard: You don’t think it’s true?

MG: Well, I don’t know it’s true, but I don’t agree with that. I think that first comes reality. Not just reality, but the parts of reality that we can observe. Then our minds try to make sense of what’s going on, creating concepts which are useful to us.

So, for example, if you go way before mathematics, if you were a hunter-gatherer in some forest and you couldn’t distinguish between the brush and a panther, you die.

So, clearly pattern recognition was incredibly important to the survival of humanity way before there was mathematics. So our brains were moulded in such a way to favour certain things over other things so that we could thrive in an environment which was very hostile. One of them was the notion of pattern recognition. The other one was the notion of ordering. So you wanted to order things – you order space; you order time – so we created this mathematics and then the science based on this mathematics because it was very useful to us.

And so, to me, what we are trying to do, is we are trying to use our minds to describe the portions of reality that we can. And then, of course, as we evolve as a species and we learn more about reality, we pluck more math and more math and more math to do that job. And so there is a very productive, symbiotic relationship between our minds and reality.

But the notion that there is a grand plan in nature which is mathematical, and we’re just trying to uncover that, sounds to me very crypto-religious. It’s very much like some sort of medieval cult and that God was this supreme mathematician, and the job of scientists is essentially to uncover the Truth – with a capital T – which is reading the mind of God, so to speak.

Ard: And you don’t like that?

MG: I don’t like that.

David: I love the idea that you’re part of a medieval cult! This is great! This day is getting better and better.

Ard: That’s why you want to be careful around me late at night! But you don’t like it because you think it smacks too much of religion?

MG: I don’t think we need that. I don’t think that we need that in order to make sense of things…

David: Even if we, as you were saying, create the beginnings of mathematics, isn’t it that once you’ve created it, there are a whole load of consequences which flow from that first stuff? In some sort of theoretical sense, all of those consequences of what you started with, they’re already there, and you are now going to discover them.

So there is a process of discovery. In other words, we’re not free to make up the next bit of mathematics any old way. The next bit of mathematics is already decided because of the few things we invented at the beginning. So in that sense we really are. So you could forgive people for thinking, ‘My god! That was there before I got there. It was waiting for me.’ Because, in some sense, it really was. It didn’t need to be put there by God, did it? It was just a consequence of the first few ideas that we had.

MG: Could you argue the same way about music?

David: Precisely. I would say yes.

MG: Because, you know, music is… once you have the notes, everything else follows. So any species that is intelligent enough to understand that there are musical scales can come up with all the symphonies that… because they’re just waiting there to be discovered, right? And I think they are not. They are just being created by this very clever neuronal network that we have in our heads that allows us to do these wonderful things. I think… Let me put it another way…

David: Okay, go on.

MG: I think that to say that everything is out there…

David: I’m not saying everything.

MG: But it’s taking away from how amazing humans are.



David: Can we go back to reductionism? You said you felt that there was… we’d come to the end of that particular kind of science. What did you…?

MG: I wouldn’t say that. No, I don’t think you can…

David: What did you…?

Ard: There’s a danger of reductionism, at least?

MG: Reductionism has been physics’ best friend, in the sense that it’s been so useful as a way of making sense of what’s going on, because what it does is if you have something very complicated, you break it into little bits, study the little bits, put things back together again and hope that the total is the sum of its parts.

And the ultimate goal of reductionism, of course, is to reduce everything to the simplest possible components. So this notion goes all the way back to atomism, the old notion of atomism from Greece, where matter is made of little things, and hence you just have to put them back together again like Lego, like little Lego blocks.

Ard: So reductionism is this idea that you can break it into the parts, but the whole is nothing more than the sum of the parts?

MG: Exactly. And that’s true for many systems. But it gets harder when the systems are not so well-behaved and they have many, many interacting parts.

But there is a place for reductionism in science, obviously. The fact that every atom of hydrogen is the same around the universe is a triumph of reductionism. And it’s true, they are the same. There is this fundamental repetition of these basic building blocks.

And that’s why it’s been so tantalising to extend this notion to everything there is. So people have tried to do mechanistic models of pretty much the mind, and the weather, and…

David: Life.

MG: …life, and even economics. And those things just don’t do very well.

Ard: And they don’t do very well because those are things that are emergent in some way or the other?

MG: They don’t do very well because sometimes, depending on the complexity of the system, if you have a system that has many parts, they interact with one another in what we call non-linear ways. So a non-linear interaction is if you kick, a rock it kicks you back in the same way. In a non-linear world with non-linear forces a small stimulus can create a huge effect, and vice versa. So it becomes much harder to predict the behaviour of a system which has many parts doing that at the same time.

The thing about reductionism is that it tries to make the universe into a big machine, like clockwork, and that is a very old idea from the 18th century, 19th century, where, if everything is mechanistic – there is this big engine behind everything – then everything is explainable and everything is predictable. This is the ultimate determinism.

And the consequence of this is that if everything is predictable, so is behaviour, so is what I’m going to say now. And that makes us a prisoner of this machine. And that tells you that you’re really not a free person: that there is no such thing as free will.

And that’s why the Romantics were so pissed off at the scientists, because they were saying, ‘Hey, it’s all a big machine.’

And they would say, ‘Wait! Wait a second. What about love and feelings and confusion and doubt? Where does that all fit into this new science you guys are talking about? That’s not the whole picture. It cannot be the whole picture.’

So that is where reductionism starts to flounder. Because, basically, it’s trying to do much more than it can, which is to predict the future in a way which is 100% accurate, and we know now that that’s not possible.

David: And is that dangerous for science, do you think?

MG: It is dangerous for science, because whenever science says that it can understand everything – including who you are, and who you’re going to be, and how you’re going to grow up – it’s robbing people of themselves. It’s basically killing their persona, in a sense, and saying, ‘You really are just a mountain of atoms, and if I know how to crank this machine, I’m just going to tell you who you are,’ and that just makes you dumb. It makes you into an automaton, and nobody wants to be an automaton.

David: It robs the world of meaning, doesn’t it? It says there’s just the machine. Someone’s turning the little handle on the machine, and it doesn’t mean anything.

Ard: Well, no one’s turning it. The machine’s just…

David: Well, it’s turning itself.

Ard: The machine’s just kind of rattling along. You may think that you’re doing something, but actually it’s the machine that’s rattling along. And so, there is no self…

David: Does it rob it of meaning?

MG: Well, it does because it basically tells you that there’s no point in searching for anything because everything is already written. There is no point in trying to understand who you are, because who you are is really pointless. It’s about electrons interacting in this big complicated way, and nobody likes that, right? I mean, you want to be able to be mysterious. People want mystery before they want reason and certainty. I think people need to not know.

Ard: But just to interject… Some people are saying, ‘Well, that may be the case that you want this, but I’m sorry for you.’

David: Yeah, grow up!

Ard: Grow up, yeah. Grow up and face the cold, hard reality that we are nothing but a bag of chemicals.

MG: Oh, we are definitely nothing but a bag of chemicals, but we have no clue how to predict how that bag of chemicals will behave.

Ard: Okay.

MG: So to say that reductionism fails doesn’t mean that there is more to it than matter. It doesn’t mean that there is some sort of soul or spirit that is controlling stuff. It just means that science cannot do that job, and I think that’s a wonderful thing.

People ask way too much of science. Some scientists, the ones that push reductionism all the way to the end, they are asking science much, more than science should be able to answer, which is to answer everything.

Science was not designed to give us all the answers. In fact, science thrives on ignorance. We need not to know in order to create new knowledge. And so this belief, because it’s nothing more than a belief, that science can probe into the behaviour of everything and come up with final answers about who you are, or even about what nature is, it’s really a misunderstanding of what science is about and how science actually operates.

Ard: But I think the argument sometimes goes like this: ‘Well, we don’t yet have a science of free will, or who you are, but we will one day. Because we didn’t used to have a science of gravity, but now we do. We didn’t used to have a science of quantum mechanics, but now we do. And so, one day we’ll have a reductionist explanation of everything in Marcelo Gleiser based on the atoms in his body.’

MG: And that to me is like a prayer. You know, like praying. You know, to me, what’s really important, right, is that we are creatures that look for meaning in everything that we do. We want to feel justified in our actions, and those scientists, you know, who are saying that there is an ultimate knowledge, that is their search for meaning.

Ard: Yeah.

MG: That’s what makes their lives meaningful. You know, if there is anything that says what is the meaning of life? Right? Well, the meaning of life is to live a life full of meaning, and that’s exactly what they are doing in their own way. So, if they believe that you can understand everything, then, that is the ultimate quest of the rational mind, and you dedicate your life to that, that is what gives them meaning, and that is awesome.

Ard: Yes.

MG: You know, good to them! And what I’m saying is that there are other ways in which we can find meaning in your life. To me, the way I look at this right now is… I look at what we learned about the universe, what we have learned about all the planets outside of Earth, what we have learned about how life evolved in this planet – and we know how rare Earth is and how rare we are as a species, an intelligent species, the, sort of, stardust that can actually think –  and that brings us back, we humans, to the centre of things. You know, not in a Copernican way, that we are the centre, but in the fact that we, like Carl Sagan said before I did, are how the universe is thinking.  And because of that, and I have my little crusade here, we should be guardians of life, and specifically of this planet.

So, to me, this new science, instead of saying, ‘Oh, the universe is enormous. We are nothing. We are just machines. We have no free will’, no, we are actually incredibly important because without us the universe wouldn’t have any meaning, because there would be no one to think about meaning in the universe.