The theory of everything is a fabrication – natural philosopher

SS: So you put forth an argument that reality, as we perceive it, is always limited by our knowledge of it, which is also always limited. So what in fact is knowledge then? Is it accumulated personal experience about something? Or can there be more to it?

MG: Yeah, so I think that's a good and difficult question. I think you can think of knowledge in different ways, and they depend on the context. So for example, you can have experiential knowledge of the world without any sort of scientific background. So, you know there is day, you know there is night, you know there is winter, you know there is summer. And so, that is knowledge and it's based on the experience of being alive and of being out in the world. And we humans all kind of share some level of that knowledge, depending where you live. But then you also have more specialised kinds of knowledge and that will depend on the specialisation. So a geologist will have the knowledge which is based on his or her knowledge of rocks, and how tectonic plates move, and an astronaut will know about spaceships and how to spacewalk. So knowledge really is an accumulated amount of information that we have vetted over time to be reliable – at least, the good kinds of knowledge, there is also the bad kinds of knowledge, like false knowledge and misinformation. And so, to a certain extent, you can think of knowledge also as a measure of belief, – you know, you believe that this information has value for you.

SS: But let's say science is a tool of acquiring knowledge, right? But what if a scientific discipline itself is actually based on no solid facts at all? If you take quantum physics, which is all guesswork and presumptions, or philosophy, which is often an interpretation of other people's interpretations?

MG: Hmm. So I would not think that quantum physics is really that loose, you know, if you think about it, actually, quantum physics is the science that is best validated by experiments that we know, in a sense that it makes predictions and those predictions – you go to the laboratory and you test those predictions, and they're incredibly successful. So in practical terms, and the fact that I'm talking to you all the way from the northern United States, and I think you are in Georgia, if I'm not wrong, that means that all this digital technology that we are working on, actually is based on quantum physics. So it works really well. The problem with quantum physics is we don't know how to interpret the mathematics that we work with. So it's a more of a philosophical issue about quantum physics, which we could talk for hours about. But in terms of reliability, it works really well. Philosophy – if you're gonna contrast philosophy with quantum physics, you're right. I mean, they are very, very different things because in philosophy you don't have what scientists call empirical validation. That is you don't go to the lab and test someone's idea about the nature of space and time in metaphysics or something like that. And that is why philosophers love to talk to one another, hardly agree with one another. And some of the questions are as old as philosophy itself, it's pretty crazy really. If you look at the history of philosophy, and you talk about the first philosophers in the West, you know, the pre-Socratic philosophers in Greece like 600 years BCE, they were asking questions that we're still asking and disagreeing about, like, the nature of matter, the nature of justice, the nature of beauty, and that is because philosophy really is about contemplating questions that are not obviously… There is no definite test about this is the way it is or this is the way it is. And so yes, you have a lot of room for argumentation, but not in quantum physics.

SS: Okay, so here's another question. What makes ‘knowing’ different from ‘thinking’ or ‘believing’?

MG: Right. So let's use the word ‘knowing’ in a more concrete way and say that if you're talking about scientific knowledge, you're talking about knowledge, which is based on... There are two parts to it. One of it is ‘okay, I have an idea that the moon is going to appear in the sky tonight’, and I can go tonight, and I can see, ‘Oh, there is the moon’, or I can see, ‘Oh, no, there is no moon’, and you may be patient and wait a while to understand that, well, the moon didn't show up because it was not a full moon or a quarter moon, but it will show up eventually. So this is knowledge that you obtain by looking at things and making... So humans are really wonderful –

SS: So experiencing firsthand?

MG: Yes, right. And we take notes, we tell stories, and with those stories, we create knowledge, and this knowledge is shared across generations. And with scientific knowledge, there is the observation, and there is the community. You know, it's really interesting. So when is a scientific idea accepted by the scientific community? Well, it has to be validated, it has to be vetted. So it's a community consensus that will decide if an idea is right or wrong. Let me give you an example. In 2012, this new famous particle called ‘the Higgs boson’ was discovered in CERN in Europe. What does it mean that it was discovered? It was discovered because the observations that were made showed a little bump in a curve with an excess of energy there, and then you had 5000 scientists looking at that picture and saying, ‘Okay, is this a new particle? What is this thing?’ And there was a long process of vetting that observation to say, ‘Yes, that is a new particle. It's not a statistical anomaly’. So it's an interesting confluence of what you see of the world, and how a community thinks about what you're saying. So it's a little tricky, but it works.

SS: But let's take a simpler example. Let's say, knowledge has to be based upon something solid, right? Do we only know something that we've experienced firsthand? What I mean is, like, I can know, let's say, all about coffee: where it grows, how the beans are collected methods of roasting, how much caffeine a cup of coffee contains, everything. But if I never tasted coffee, do I truly know what coffee is?

MG: That's a beautiful question. I love it. Because there is a fundamental difference between sort of the knowledge on paper and the subjective experience of having knowledge of something. And this is a question that goes right into the issue of what is consciousness? So it is connected with what some philosophers called ‘the hard problem of consciousness’, which is a really interesting question, which is, can we humans really understand what mind is? Can we really understand what consciousness is? And one of the examples that people do when they're arguing about what is consciousness, is precisely the nature of subjective experience. So for example, let's say, just to compliment your excellent example of coffee, especially being Brazilian, I take coffee very seriously. It's the notion of colour. So you're wearing a red shirt, a dress, I can't really tell because we're all sitting, but it’s red. And I have an experience of that colour, red, and somebody else in your show is going to be looking at that colour, and they will have an experience of that colour, and it's a subjective experience. If you told me the colour red is an electromagnetic wave that has a certain frequency and this one has a certain intensity and that defines what the colour red is, that would tell me nothing about the experience of feeling, subjective experience of experiencing what red means. And you're right, you cannot just theorise about something. You need to have some sort of experience about it because we humans are animals that live in the world through our senses. And so you can hypothesise and theorise about all sorts of things, but that doesn't mean that they will correspond to what the world really is like. There is a joke that if you put down theoretical physicists in a room and tell them, ‘Describe the world outside this room’, their ideas will have nothing to do with the world until you have data. Then data is this bridge between us and the world outside of us and we need that.

SS: I want to examine a bit scepticism because if science as well as religion, let's say, are tools with which humanity has been trying to deal with the unknown, what's the use of scepticism then since it doesn't really give answers like science does, but only makes things even more confusing?

MG: Well, I think scepticism is related to doubt, and it's a wonderful tool so that you're not fooled by what people tell you. And science in a sense is perhaps one of the best tools for us to use in order to not be fooled by what people tell you, in a sense that, you by knowing how to think critically about stuff, you are not going to believe the first thing they tell you. So if they say the Earth is flat, like unfortunately, lots of people nowadays are thinking, you know, it's a very sad story but it's true, you have thousands and thousands of people in the world today who say, ‘The Earth is flat. Period.’ And it's painful to hear that. Are they being sceptical? Or are they being ignorant? So there is a difference between the two things. So a sceptic is a person that is going to ask questions, pointed questions, to try to make sense of some statement, so as to believe that statement, or not believe that statement. And that is a very healthy thing to do. If I tell you that atoms don't exist, or the atoms do exist, you know, a sceptic is going to say, ‘Well, how can I know?’ and then you go through the whole song and dance of ‘Well, this is what laboratory experiments tell you’. But if you don't ask questions, ‘Okay atoms exist’ or ‘Okay, atoms don't exist’ you're not really exercising your freedom to think about stuff in a critical way. So you're just being like a sheep, you know, going with whatever they tell you. And in our days of the internet, where there is so much information and misinformation, scepticism is a very important tool for us to actually learn something from what we're being able to watch out there as opposed to being fooled about stuff like UFOs or life after death and all sorts of other affirmations.

SS: When you discuss science and religion, you say that, like a religious person, a scientist who's making a discovery is guided by faith, not yet fact. So are the belief in creative progress and the religious belief the same deep inside? Let's say, is our technological progress ultimately based on the same thing Christianity is based on? Or are the two fundamentally different types of beliefs?

MG: Yes, they are two fundamentally different types of beliefs. And I'm glad you finished by saying that, because in the case of religion, faith does not have to be confirmed by observation. I mean, if you believe in God, you don't care if you're going to see God, or if God exists in a concrete kind of way. You believe in God and that's all you need in order to have faith. And in science, you may have faith in an idea and you could give your life, your whole career, decades of work to prove that that idea is right, but you know what, if eventually, data proves that the idea is wrong, you have to abandon that. And with religious faith, or religion, there are different kinds of gods out there in the world, you do not need that ultimate test in order to – which doesn't mean that people that have faith do not have doubt. You know, I mean, you may be a religious person, and I have talked to many, many religious people over my career, and one thing that they do say is that, you know, believing doesn't mean that you're never in doubt. In fact, doubt is part of religious belief as well, because, you know, a very obvious question that always people ask about God is that if there is God, how come there is so much suffering in the world? And people that believe, when they confront suffering in their own private lives, they say, you know, ‘Why did my cousin who was 10 years old die of cancer?’, something horrible like this. You may doubt your belief, but it's a different kind of doubt than a scientific doubt on an idea that eventually will be vindicated or not by experiments. So, yes, there are different kinds of faiths.

SS: Also, I heard you saying that the pursuit of an equation that would explain everything is a cultural consequence of monotheist faith, that theoretical physicists are just looking for God. But on the other hand, countless generations of humans have been looking for God, and now the physicists are trying their hand at it. What's wrong with that? Maybe it's worth it? What if they really find God? You never know, do you?

MG: Well, so that's an interesting proposition, you're saying that if I have a theory of everything from a scientific perspective, like in physics, you know, that is the scientific equivalent of God. And I actually made that almost like a joke, really, saying, in a sense, that you could think of this theory of everything in physics as God, but you have to be careful with that. Okay, so let's be a little careful with that. First of all, when physicists talk about a theory of everything, they don't really mean everything with a capital E. They mean understanding how the fundamental particles of nature interact with one another, and how gravity works. So it's about forces and particles, a very materialistic theory of everything. And it's not really a theory of everything that is going to say, ‘Oh, yes, I knew Sophie was going to invite me to this show because I know the theory of everything and I can predict everything’. That does not belong to this sort of physical theory of everything. So we have to be a little careful about that. In fact, a lot of the people that work on superstring theory and other ways of looking for theories of everything, would be horrified to say that they're looking for God through physics. But the point is this, in a sense, they are. And that's why I like your question because you have to look at science – and this is something that I've done a lot through my writing, – not just look at science, but the cultural context in which science actually is created. And if you look at it, this notion of unification started in ancient Greece’s philosophy, as it was before created religions in the Middle East, Judaism, and then Christianity, etc. And the idea of unity, that everything comes from a single source is incredibly powerful in our way of thinking. And a Hindu person would not think that way, you know, because they have gazillions of gods. So for them, there is maybe unity in the ultimate-source-of-all-gods kind of thing, but it's not as compelling as this notion that everything is one. And I am all for looking for unity in science. In fact, my PhD and for many years in my career, I was doing superstring theory and looking for unification too. But as I grew older, I started to realise that you can pursue a theoretical dream for a long time, as long as there's some sort of data backing you up. And what has happened with the theory of everything is that decades have passed, we're talking about 50 years have passed, you know, people have been looking for this. And actually even before we got Einstein, – you know, Einstein spent the last 20 years of his career, looking for a theory that would unify gravity and electromagnetism, and he failed. And, and everybody has been failing ever since, and not just from a theoretical perspective, it’s super hard to do, but data is just not helping us. Everything that we hoped to find in the last 20 years at the same machine that found the Higgs boson, you know, the LHC at CERN in Switzerland, we haven't found it. So it comes to a point where do you draw the line between stubbornness and blindness? You know, you just don't want to accept that this big grand dream of a theory of everything is more a theoretical fabrication than what nature is telling us. And I started to think that way.

SS: But your last sentence makes me think even more that if there is a slight possibility of actually knowing everything, then that is God because I've had so many interviews with a lot of different people of science. For instance, I had dozens of interviews with astronauts, and you know, these are people of science, you know, they've been taught like scientists to go to space, and then they tell me, ‘We started believing in God the minute we left Earth because when you look at everything, there is no possible explanation of how this is possible unless there is God’. And then I have this really famous elderly lady who is a neuroscientist, and she is like a full-on scientist, and she says, ‘The more I study the human brain, the more I understand that except for God, nothing could have created this’. So what I'm saying is that if you know everything, isn't that God?

MG: If you could know everything, but you can never know everything as a human.

SS: Okay, so you suggest that at one point in the furthest imaginable future, there will never be a moment when there will be nothing left to learn, right?

MG: I really don't think that's possible, yeah. And that's what this book ‘The Island of Knowledge’ is about and I can tell you why. Let's imagine this, and I'll tell you what the island of knowledge is because I think it's a good image for people. Let's imagine that everything that we learn about the world fits on an island. So as we learn more and more, because we are learning more and more, this island grows. Now, as any good Island, the island is surrounded by an ocean, in this case, it’s the ocean of the unknown, of stuff we do not know. And the paradox of learning (and this is what the point is) is that as the island grows, the boundaries between what is known and what is not known, are also growing, which means that as we learn more stuff, we are able to ask questions that before we couldn’t even have thought about. Let me give you a very practical example. The microscope was invented in the late 1600s in Holland. Before the microscope was invented life was something. After the microscope was invented, people started to look at a drop of water, and they said, ‘Oh, my God, look at that! There are all these little creatures moving around in the drop of water! So life is much more complex.’ And then all these new questions about what is life emerged from this new tool. And knowledge is always like that. If you look at the history of science, you know, as it moves on and on and on, you invent something like we talk about computers now, so everything is information, so I could give you a whole interview about the world is information and information is absolutely essential, etc. And that's because this is what we know now, and this is what is allowing us to ask these questions. So the paradox of knowledge is that by knowing more, you also not know more. And this pursuit, as long as you have funding to keep asking questions, is in principle, infinite. You know, infinite is, of course, a crazy word that doesn't make a lot of sense. But as you push the boundaries of knowledge forward, new questions will always emerge. And just to make things more interesting, in this ocean of the unknown, there are little regions of unknowables that are fundamental questions that you can ask scientifically, that you cannot answer with the science that we have today. So unless you change completely the way science works, there is no way you could answer these questions with the science that we have today. For example, the origin of everything or the origin of life on Earth, – do we really know how life could have emerged on Earth 4 billion years ago? Not really, you know, you can have life in the laboratory, you can make it but that doesn't mean that you know what happened 4 billion years ago. So there are questions that you can ask, which are good scientific questions, but the framework of science could not give you answers. So that's why I'm an optimist because the fact that we will always not know something means that scientists will always have employment, will always be able to be working.

SS: Here's a very human question because we, humans, are used to always sort of aiming at a goal and reaching a hill and actually getting there. But if you're saying that we're all going to be like Sisyphus, never reach the top of the hill, always kind of stay ignorant, what's the point of everything, then?

MG: Ah, here we go. So I'm a mountain runner. And I actually have used this exact analogy in a different way, which is the following. So you're going up the hill and this hill, this mountain is your objective, right? And then when you get to the top of that mountain, there are two things you can do. You can look down and you can say, ‘Ha, I reached my objective, I'm done’. Or you can look around and you can say, ‘Oh, no, look, there are all these other mountains, taller than this one, so that I can keep climbing bigger and bigger mountains’. And then when you climb the biggest mountain of them all, you go and you look up and there’s the whole universe to explore. So it's just a matter of attitude. And to me, you know, there is always something new to learn.

SS: It's been such a pleasure talking to you. Thank you very much for this insightful conversation about knowledge. I really hope we get to see the next book very soon and we get to do this again.

MG: Happy to, Sophie, absolutely. I'll talk to you. 

SS: Thank you. Take care of yourself.

MG: Alright. Bye.