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25 Oct, 2019 06:56

We all use quantum mechanics but can’t agree on what it means – physicist

The last century was marked by mesmerizing scientific breakthroughs. But have we come closer to understanding how the world around us functions? We talked to physicist, humanist, popular science author and broadcaster Jim Al-Khalili.

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Sophie Shevardnadze: Jim Al-Khalili, thank you very much for being with us today. It's been a while we wanted to do this interview with you, actually.

Jim Al-Khalili: Oh, thank you. 

SS: Because you're a man who fits perfectly the formula that I live by. I think genius is very simple, and you tend to explain what we think are super complicated things, and you put them into simple terms, so it’s sort of accessible to the general public. I’ve got a lot of questions. 

JK: Ok.

SS: Let’s start with the very obvious ones. There are plenty of warnings from the scientists nowadays about the inventions that we're currently working on, like the artificial intelligence or the robotics, or even the biological dangers. When you think about it, before we thought that science was the way out for the bright future. Now, more time passes, I get a sense that it actually may be turning into a tool of humanity’s demise, in a way. 

JK: Well, Sophie, I'm an optimist, and so I still think science ultimately is going to have to… You know, we need it to save humanity. Science is not good or bad. It's neutral, it’s knowledge. And knowledge, enlightenment is always better than ignorance. It's how we put that knowledge into use. So something like artificial intelligence, and robotics, automation… Yeah, sure, people are nervous. They're nervous about whether robots are going to replace their jobs. They're nervous about the whole “Terminator” movie scenario of machines taking over the world and becoming more intelligent than us. But AI is coming. It's already we're starting to see artificial intelligence happening, and we can't slow it down. My message tends to be “Let's make sure we're ready for it”, not “Let's slow it down or stop it”. But regulations, ethical considerations, and that goes for lots of other areas of science.

SS: Right. You said, science is knowledge. But beside knowledge, it has become a real tool of ruling the world and with everything that is wrong right now with the world and in the world you're almost certain that science will end up in the wrong hands for the wrong purposes. No?

JK: I certainly am concerned about issues such as genetic engineering, where we're moving very fast, and while some countries might put rules, and laws, and regulations about cloning, for example, other private organizations or countries may not. But we've always used our knowledge to develop technologies that change our world. You go back to the Industrial Revolution, even before that. Science has always shaped our lives. Sometimes it's for bad purposes… We've used it for evil, for building weapons of mass destruction. Sometimes it's for good reasons, for developing…

SS: The man, who invented lobotomy, got a Nobel Prize, so yeah. 

JK: Right. Okay. Well, you know, there are some interesting examples. But I think about the advances in medicine. When people say, “If you could build a time machine, what time would you travel to?” Now. This is the best time to live. Despite all the problems and the issues facing humanity in the 21st century, now is still the best time to be alive, because of the advances in medicine and technology. Our lives are easier, are richer. So I'm still an optimist. I know we have huge challenges facing us in my lifetime and my children's lifetime, but I still think science can have the answer.

SS: Because it has become so acute at this point, the breakthroughs that scientists are making, feels like we're on the verge of, I don’t know, becoming a different world and a different civilisation. Do you feel scientists (because they're more than scientists at this point with all these breakthroughs), do you feel they should be maybe more engaged in society politics? I don't know, maybe have more impact on decision making. Take global warming, for instance, I know you care a lot about it. So many scientists all around the world have been saying, “This is serious! This is happening!” And then you still have elected officials saying, “Uh? We don't think it's a big deal. It’s much ado about nothing”, you know.

JK: Yeah, I think it's certainly true that scientific discoveries and technological advances are happening ever more rapidly. Maybe a thousand years ago, someone from the 10th century talking to some from the 9th century, they wouldn't have too much that wasn't in common. The gap in transformation of humanity is getting smaller and smaller. Now we look back and think, “Ten years ago, if I looked at my latest smartphone, I'd be amazed!” Things are happening more quickly. Scientists, absolutely, I think, really do need to step out of their laboratories, away from their offices, talk to wider society and think themselves about the implications and ethics of what they're doing. We can't slow down technological developments, but we need to engage with society about what it means to make sure we're ready for it.

SS: But a stumbling point here is that a lot of scientists don't know how to talk. I remember interviewing a guy from CERN, we were talking about the discovery of the Higgs boson. And no matter how hard I tried, I wouldn't understand anything, no matter how much he tried to explain it to me. And I figured, maybe this is the problem why scientists can’t communicate these breakthroughs to people. You are an amazing example of “a science PR”, in a good way. Do you think right now there are things in science that cannot be communicable to the public?

JK: Yes, I think that is true. I used to think that it doesn't matter what scientific subject we are discussing, it is simply a matter of finding the right language. The Higgs boson, your example, is a very good one. The people who developed the idea of the Higgs field and the Higgs mechanism, they've worked all their lives, 50-plus years to try to understand the detailed mathematics involved in this area of fundamental physics. What right does the wider public have in expecting it to be explained in a sound bite? The great American physicist Richard Feynman once was asked after he won his Nobel Prize, “Can you explain in one sentence what your Nobel Prize is for?” And he told the journalist, “Young man, if I could in a sentence, it wouldn't be worth a Nobel Prize.” So in a sense, sometimes some areas are complicated, but I think the wider issues, the important areas of science that impact on society (like climate change, like artificial intelligence, like our world's energy needs and food resources, like advances in medicine), yeah, we should be able to explain them at least the important aspects that the public need to be aware of. We don't expect everyone to become an expert, a brain surgeon, or a rocket scientist, or a nuclear physicist, but they should be able to understand the basics.

SS: So we are going to get to artificial intelligence. But I suppose there are some things that still can be explained in a simple way. For instance, physics has come a long way from apples falling on heads. Right? It has become some sort of magic to people who don't really know it, especially when we're talking about quantum physics and quantum field. It’s still mind-boggling for me, how you can be looking at one thing and it's one thing then, and then it's a different thing when you're not looking. Can you explain to me, how is it possible that an electron can be in two places, at two points at the same time? OK, let's drop the “how” and “why” part- 

JK: Okay.

SS: I'll just accept it as a fundamental truth.

JK: Okay. 

SS: But why that can be in two points at the same time, and a tennis ball can’t.

JK: Quantum mechanics is a great example because it is a very counter-intuitive scientific theory. We've had it for almost a century now, and yet, if you ask a quantum physicist to be really honest, they will tell you they also find it baffling, ridiculous, because it describes a world, the world of the very, very small, the level of atoms and the particles that make up atoms, which is a very different world from our familiar world of tennis balls. But it seems that's how our universe, how reality is at these smaller scales. So quantum mechanics is a powerful theory. It's very precise. It has helped develop so much of modern technology. Without it, we wouldn't have computers, we wouldn't have smartphones, we wouldn't have so much of modern technology, because quantum mechanics describes how electrons behave. But as you say, an electron being in two places at the same time is crazy. Part of the problem there is language, because to really get a correct view of what the quantum world is like, we need to describe it mathematically. Nature speaks the language of mathematics. If we convert it to human language (English in this case), then inevitably we are losing some of the subtleties. An electron isn't really in two places at once. The mathematics suggests that there's a probability of finding it here or there. And until you look and measure it, you cannot know. But quantum mechanics doesn't tell us what that electron is doing when you are not looking at it. And there are different philosophical ways (they're called the interpretations of quantum mechanics) that tell us different things about what that electron is doing. Maybe the universe is split into two, maybe the electron is like a spread-out cloud, maybe the electron can communicate instantaneously across the whole universe. There are all sorts of… But the weirdness is there, and that's what makes it for me so fascinating. But it's just crazy! 

SS: But when you say “weirdness”… Okay, that could be just an adjective to describe what you love. But do you have any doubt in what you love? Are you absolutely convinced? 

JK: Yes, scientists always have to have doubt. You know, that's built into our DNA that you cannot be certain of anything because tomorrow a new experiment or new observation might be made, which will suggest that my theory, quantum mechanics, for instance, was wrong all along. But in as much as I can be confident, I would say that I'm pretty, pretty sure that quantum mechanics is correct, and it’s the correct description of reality. You know, without quantum mechanics, we wouldn't have understood how semiconductors work. They're not metal conductors of electricity. They're not insulators like plastic or wood. They're in the middle. A semiconductor is… You know, a silicon chip is a semiconductor. So without quantum mechanics, we wouldn't have developed silicon chips. We wouldn't have had microchips, or integrated circuits, or computers. And if you look now at the world around us and how much our lives have been transformed by computers and hence the Internet and so on and so forth, none of that would have been possible if quantum mechanics wasn't correct. 

SS: So you're saying, “Just drop the philosophical side and stick to the practical side”? 

JK: I'm saying you can. You can do if you just want to be a pragmatic, what’s called “an instrumentalist”. This is someone who doesn't care about all the philosophic detail. I just want to use it. For me, that's almost… 

SS: But you dig the philosophical part of it?

JK: I like it, because I'm a physicist. I mean, in a sense, I'm talking about the distinction between a scientist, a physicist and an engineer. A physicist has all the deep thoughts. An engineer wants to use the knowledge to do something useful in the world.  

SS: It's kind of like a historian and a writer who writes a literature book about that period of time. 

JK: I guess so. Yeah, I guess so. I think a physicist is curious about “how”. How is that electron doing what it's doing? An engineer will say, “That's fine. This equation will help me develop something that will improve humanity, something useful.” But for me, I'm still obsessed with the underlying philosophy of how it behaves the way it does. 

SS: You have once said that you would really hope that scientists will at some point work on quantum teleportation. At this point, we know that scientists have been able to teleport information. Do you think that we could at some point teleport matter?  

JK: In theory, in principle, it's possible.  

SS: How would that work? 

JK: Well, if you can teleport information so you'd have to have… You know, if we think about a single particle, not even an atom, a particle that makes up an atom, an electron, say, or a photon, a particle of light, to teleport that photon from there to there, you're not actually moving the matter, you're moving the information. That is what's being transferred. So you're not moving a material object. If you extrapolate that, you want to move a whole lump of material in a particular arrangement of atoms, you need to have the raw material in the other place already. And the information is transferred to reconstitute what you had originally. So in “Star Trek”, when Captain Kirk is transported down to a planet, it's not him. It's not the... I mean… 

SS: Yeah.

JK: Physics says that it's not actually him. There have to be atoms of oxygen, and carbon, and nitrogen, and hydrogen, and all the other atoms that make up a human – all have to be there. And the information about those atoms that make up Captain Kirk in that arrangement, all that information has to be transferred to reconstitute him on the planet's surface. But that information is incredibly complex. We can talk about transporting information about one particle, but when you have trillions of particles arranged in a very special way to make up a living human being, it's almost inconceivable. 

SS: I was going to ask if there is a such thing as a teleport in the foreseeable future, would you step into it, honestly? 

JK: Well, that becomes quite an interesting metaphysical question, because if it does work– 

SS: Can you transport consciousness with the atoms of your body? Wouldn't that be kind of death? 

JK: Well, for me, I would say that consciousness is a particular state of the atoms, the neurons that make up my brain. Consciousness isn't a magical extra thing. I'm just made of atoms ultimately arranged in a special way that are thinking and now talking to you. So if we're teleporting me, we are also teleporting my consciousness. But, of course, my philosophical problem will be that it's not me that has arrived at the other end. It's a new version of me.

SS: It’s the information about you, right. 

JK: And I'd be a bit worried about any glitches or…

SS: Right. 

JK: …or errors. 

SS: Where would the real you be stuck in all this, right?  

JK: Yeah, exactly. So you know what is a real me? Similarly, if you make a clone of me, which one is the real me? Is there such a thing as the real me? That's an interesting philosophical question. But I don't think teleportation is going to happen in my lifetime, if ever. I think it's hundreds of years in the future.  

SS: Another thing that you always talk about is quantum biology, and that's marrying quantum physics with biological processes. Most of your books are very much about how the world that we're living is governed and depends on quantum biology. Can you give me some very obvious examples?  

JK: Yeah. I mean, this is a new field. It's still somewhat speculative. I would dare even say controversial. Quantum mechanics has been used in physics, so we have quantum physics. We have quantum chemistry. But quantum biology is new. And part of it is historical because when quantum mechanics developed in the 1920s and 30s, it was developing at the same time as biology was developing genetics and molecular biology, and molecular biology and genetics didn't need quantum mechanics. Now we're starting to see particular examples of where maybe quantum mechanics is necessary to explain the processes of life, for example, in photosynthesis, the way a plant leaf captures sunlight and converts it into chemical energy. One stage in that very complicated biochemical process requires… You talked about the electron being in two places at once. In this case, it looks like that photon, the particle of light, follows multiple routes through the cell simultaneously. One photon moving in lots of directions at the same time. If it sounds ridiculous to you – exactly! Welcome to quantum mechanics! But in my view, if quantum mechanics… If life has had for nearly four billion years to find tricks to develop and to evolve, and according to Darwinian evolution, if quantum mechanics offered an advantage, life would have found a way of utilizing it. So maybe now there are half a dozen or so different examples. So if photosynthesis is one– 

SS: What kind of mysteries can quantum biology uncover about life on Earth that we don't know at all about?  

JK: Well, we simply don't know. At the moment we're just looking at very specific mechanisms saying, “It looks like that would only work if that particle was behaving in a quantum sort of way”. Maybe, you know, our sense of smell or the way certain animals sense the Earth's magnetic field for navigation. We know they do that. Maybe they use some quantum trickery to do that. So these are very specific examples which are not going to change the way we see the world. But the bigger picture, even more speculative, is that maybe life is special because it can use quantum mechanics in a way that inanimate matter cannot use. Because one of the big questions is “What does it mean to be alive? What is the difference between life and non-life?” Maybe quantum mechanics has a role to play in answering that question.  

SS: From my understanding, quantum biology is also very much about DNA, the importance of the DNA mechanism in general. Do you think breakthroughs in quantum biology could bring us closer to gene editing? 

JK: Possibly. I mean, the whole area of genetic engineering and gene editing seems to be moving very quickly without any quantum mechanics. Thank you very much. But of course, we are not talking about individual particles, protons, which are the nuclei of hydrogen atoms. They are being moved around. They form the glue that holds the DNA strands together. But when you talk about protons, you're talking about the world of quantum mechanics. These particles are so small they behave according to the rules of quantum mechanics. So it's crazy to think that those processes down at the level of biomolecules in DNA don't obey the laws of quantum mechanics as well. So maybe quantum mechanics is going to be necessary to really understand that. 

SS: How difficult is it to be working in a field that is still largely theoretical? Is it hard to get funding and grants from bureaucrats? 

JK: Well, I'm lucky I work in a university where we are expected to pursue sort of curiosity-driven research. We don't have to justify. If I was working for an organization or private company, they would want to know, “What is the product that your science is going to help us develop that we can sell to make money?” In a university we don't. We can pursue intellectual curiosity. Blue sky research. It's always difficult to get funding, but there are mechanisms involved. You apply for grants, and then they ask you to think and come up with theories and ideas and developments that may, of course, one day have an application. 

SS: So you've done that all your life, come up with theories. And you’ve thought about theories of others. How much in general do we know about universe? I mean, how much holes are there in our perception of the world in percentages? Do we even know 5 per cent of how things work? 

JK: It depends who you talk to. You're talking to me. I think there have been stages in the history of science, and physics in particular, because physics tends to be the most arrogant of the sciences. You know, we are dealing with the biggest questions, the fundamental issues of reality. And there've been periods when we thought we were almost there. The end of the 19th century: we thought, you know, we had electromagnetism and thermodynamics and Newton's mechanics, we could understand the universe. And then we discover x-rays. What is that! We discover radioactivity. We discover the structure of the atom. And suddenly there's a new revolution by the beginning of the 20th century. Einstein comes along. The pioneers of quantum mechanics come along. And then the end of the 20th century: people like Stephen Hawking were saying… He famously wrote a paper, maybe about 1980, saying we're coming to the end of theoretical physics, almost everything is understood. Now we realize all the matter in the universe that we know of is only 5 per cent of the stuff out there. There's dark energy and dark matter. We have our two most successful theories – quantum mechanics and Einstein's relativity, and we don't know how they fit together. So my view is that we still have a long way to go, and that's great! Because I want for there to be lots more we don’t know.

SS: It’s funny you mentioned relativity and quantum together, because I was talking to Michio Kaku maybe a year or two ago. And he was like, “My goal is to combine relativity, quantum and other theories and come up with one formula that would explain everything.” I mean, is this too romantic, or is it actually possible? Is it feasible? 

JK: I'm not sure it is feasible. It's always been the sort of the headline. The ultimate holy grail of theoretical physics, is to come up with the “theory of everything”, the equation to wear on your T-shirt. I don't know how possible that is. We don't think quantum mechanics is wrong. We don't think relativity is wrong. But there are two very different theories. And then there's also the nature of time itself. I think we're moving slowly in the right direction. But I'm not sure we're going to be able to simplify it into a single packed theory that describes all phenomena. I think it's going to be more complicated than that. 

SS: Do you believe in parallel realities? Scientists who actually work with black holes and quantum physics and all of that, are talking about time travel, and they're talking about time travel not like crazy people, but like scientists. 

JK: Yeah. I mean, the first book I wrote was about time travel. It’s 20 years ago now. It's fun. I think time travel is fun. But if you asked me, “In reality, are there parallel universes?” I'm not sure. One of the most popular ways of explaining the strangeness of quantum mechanics is called the “many-worlds interpretation”. And it's a very smart idea. And it may be… I still need convincing, but it's almost like a religious ideology. You know, there are physicists who believe in the many-worlds interpretation, there are physicists, who believe in the Copenhagen interpretation, which is another view of quantum mechanics. And there are others as well. So although we all use quantum mechanics, and we all agree on the maths, and we all agree on the technology that quantum mechanics has helped us to develop, we can't agree on what it all means. And parallel realities, parallel universes is just one way of explaining the strangeness.  

SS: So it's all at this point within the realm of theory. There's nothing that actually can be observable in a scientific way. 

JK: No. We've tried for ever since almost the beginning of development of quantum mechanics in the 1920s, there have been different ways and arguments about what it all means, but we haven't yet been smart enough to come up with an experiment or test that would tell us: that's right, that's wrong. So these are called the interpretations of quantum mechanics. I still hope, for me, that's my ultimate ambition, that before I die, I will know what is the correct interpretation of quantum mechanics.  

SS: All right. Jim Al-Khalili, thank you so much for this interview. It's been a pleasure talking to you.

JK: My pleasure, too. Thank you.