Reality and the Physicist: Knowledge, Duration and the Quantum World

"So Jammer’s book was published in 1974. There were just the beginnings of an awakening of interest in experimental tests of the kind that John Bell had come up with. Even as a young student, Bell had railed against ‘shut up and calculate’, the indifference of the physics community, and as a result of not wanting to let go, he came up with Bell’s theorem and Bell’s inequality. In other words, there’s a way of explaining some of the more bizarre aspects of what quantum theory predicts if one assumes that there’s a hidden mechanism, that there are deeper principles that you can get to if you just drill down a little further. Now, there was no evidence for these hidden variables. But Bell asked, ‘if we were to assume that they exist, what could we expect to see?’ Bell’s theorem is effectively saying that for a certain type of hidden variable it will predict experimental results that don’t agree with what you’d get if you used quantum mechanics to predict the same things. That’s Bell’s inequality. I don’t know if you’re familiar with David Kaiser’s book How the Hippies Saved Physics. They were a group in the late 60s who had some fun times mixing things like Bell’s theorem and Bell’s inequality with Eastern mysticism and taking narcotic substances while sitting naked in a hot tub (this is out in California, where it was okay to do that in those days). They had some wacky ideas, but they kept these ideas alive. They weren’t the only ones. David Kaiser distorts a little bit the importance of this group, who were known as the Fundamental Fysics Group. Among them was John Clauser, who was one of the first, along with Stuart Friedman, a student, to perform an experimental test of Bell’s inequality. In other words, is there this hidden layer underneath quantum mechanics that would predict that things would come out differently? And the results were pretty conclusive. The answer is no. Quantum mechanics predicts the correct results. But there were all sorts of questions and doubts. I don’t want denigrate Clauser’s work, which was very good and highly motivational. Experimentalists continued to nag and worry about this problem with quantum mechanics. They wanted to repeat it, if not go a little bit further and make some more sophisticated experiments. It took another 10 years. In 1982, a French physicist called Alain Aspect and his colleagues at the University of Paris were the first to report definitive experimental results. These were really the earth-shattering results that most people point to when they talk about Bell’s theorem and Bell’s inequality. Now, there have been lots and lots of experiments since that have all simply deepened the realization that as far as this certain type of hidden variable is concerned, it’s not there. Quantum mechanics is correct, despite the fact that it predicts or seems to predict all these spooky things. “We’re now at the stage where we’re waiting 50, maybe 100, years before we’re able to answer a question that we want to put today” My fifth book is again a stepping-stone. Bernard d’Espagnat actually spent some time sitting in those hot tubs in California with the Fundamental Fysics Group. For me, Reality and the Physicist is a very, very good introduction to the conundrum, the realization that there isn’t an easy way out of this. If quantum mechanics is all there is, then we can still salvage some understanding of how we think reality works by producing more esoteric mechanisms that lie beneath quantum mechanics. These include something called the de Broglie-Bohm pilot wave theory where you have a wave and particle construction. The only trouble with that is that it means if I do something over here, it has to instantaneously affect something over there, even though over there could be halfway across the universe. The notion of spooky action at a distance is intrinsic to this kind of pilot wave theory. Or you can say it’s all about consciousness . This idea of the collapse of the wave function doesn’t really happen, cats are both alive and dead at the same time—until we lift the lid of the box and look and it registers in our conscious mind. These are ways and mechanisms of salvaging a sense of realism in the quantum formalism. Or you can go with what Bohr said, right from the beginning, all those years ago, that the formalism itself is a ‘a purely symbolic procedure.’ All we’ve got is experience. We know when we do this, that happens, we code for that in the mathematics and we have a finely-tuned mathematical structure that allows us to plug in what we’re going to do and predictions for the probabilities of what’s going to happen. That’s it. There’s nothing more to it than that. That’s not shut up and calculate. If you follow that logic, you’re coming to that conclusion on the basis of reasoned philosophical, logical arguments. That’s not saying it doesn’t matter. Bohr is not indifference; indifference is not science. Indifference is not really trying to push science that little bit further. For me, the Bohr-Einstein debate is the ultimate summation of what science should be, a constant to-ing and fro-ing on what we think this means. Reality and the Physicist , my fifth book, is effectively, then, a springboard to the way I structured my own book, Quantum Reality . I spend quite some time—two chapters—trying to make sense of reality and what we mean when we talk about it. We’re often so loose in the way we talk about it, I think it’s important to get some definition in there. And there’s a very distinct difference between the way philosophers think about reality and the way scientists think about reality. I wanted to bring those two together and I came up with a metaphor. You’ve got this island of ideas—the shores of metaphysical reality—and you’ve got the rather brutal, harsh shores of empirical reality where all the data sits, where all the facts are. And the ship of science ploughs back and forth on the sea of representation (yes, I’ve read too many fantasy novels ). The idea is that you build a scientific theory as a result of accumulating new ideas and the facts and welding them together. There’s tension and a mix of the two. They do become horribly entangled. You often can’t distinguish between the ideas and the facts anymore, and the ideas become part of our language for describing these things. You try and get someone at the Large Hadron Collider to explain what they do, and I can guarantee you they’re going to tell you about the standard model of particle physics. They’re going to tell you about quarks and gluons and so it goes on. It’s not clean. It’s messy, it’s profoundly noisy. It doesn’t always work. Sometimes it works brilliantly well, but then we have a scramble to understand what the hell it all means. In the sea of representation, I put two dangers based on Homer’s epics . That’s Scylla and Charybdis. Scylla is the harsh rock shoal of instrumentalism or stark empiricism. This is the ‘shut up and calculate’, the indifference almost, where in effect you’re very close to the shores of empirical reality because it’s all about the experience, it’s all about the data. Don’t worry about what it means, just plug in the numbers and do the calculation. On the opposite side, you’ve got Charybdis, which is a whirlpool of metaphysical nonsense about the nature of reality. It’s ideas bereft of any data to back them up. That’s where I put the so-called many-worlds interpretation of quantum mechanics, the idea of Schrodinger’s cat which is in some kind of fantastic ghostly state of being both alive and dead, when you lift the lid of the box the universe splits and in one universe the cat is dead and in one universe the cat is alive. It’s a nice idea and a great basis for a whole raft of movies that have been made, but in my view it’s pure metaphysical speculation. There’s absolutely no evidence for the universe splitting like this and there can’t be. I hope readers of my book will at least find it useful as a way of categorizing and thinking about all these different interpretations. But I’ve got a very bad feeling about quantum mechanics, in the sense that we could literally be at the stage where this is the final structure and there are no deeper principles, but it’s not in our nature ever to agree on that. And that’s again why the Bohr-Einstein debate is so important. There are arguments this way and there are arguments that way. I think so. With the exception of the many-worlds interpretation, which I don’t like, I’m reasonably agnostic. I believe that what’s important is the debate. What’s not good is indifference. You can’t be indifferent to this and if you’re indifferent to it and your area is quantum physics, for me, you’re not really being true to yourself. There’s almost a moral imperative to be curious about this question. Otherwise you’re betraying science, to a certain extent. The more I’ve looked at it and the more I’ve studied it, the answer to that question is unequivocally yes. If you look back at the debates that went back and forth between the founders of quantum mechanics—people like Einstein and Bohr and Heisenberg and Schrödinger—these people were from a moment in time where it was expected that to be a scientist you would be a rounded scientist. You would know some philosophy. As I mentioned, Einstein read Kant’s Critique of Pure Reason at the age of 13. There were no ‘two cultures.’ You knew some philosophy, you could play a musical instrument. That says something about the class of people involved as well, and their access to quality education. Today that is almost gone. Those who position themselves to pontificate about the grand questions in science don’t have that background in philosophy and they don’t have an understanding of history that would allow them to make more informed comments or draw more informed conclusions. The basis of my book is to say, ‘Hang on, in order to understand the nature of why this is so bloody difficult, you’ve got to understand the heavy dose of metaphysics and philosophy that exists in all of this.’ What I’m hoping that readers will come away with from my book is the understanding that you can’t just separate these two. There’s not science on the one hand and philosophy on the other. To understand how science works, you need some grounding in philosophy to understand how a scientific theory comes together, what differentiates science from stuff that isn’t science—the demarcation criterion that philosophers have been nagging about for at least 100 years and still haven’t got anywhere and some have largely given up on. It’s funny, I got hooked on these questions about quantum mechanics from about 1987 onwards. Within 18 months of getting hooked, I quit academia. My first book on quantum mechanics was published in 1992, it was called The Meaning of Quantum Theory: A Guide for Students of Chemistry and Physics . There’s a bit of maths in it, but not much. That commitment has never left me. I wrote a book called Farewell to Reality , published in 2013, which was quite a strong criticism of some aspects of modern theoretical physics, particularly string theory and the multiverse. I tried to put forward reasoned arguments—some of them based on philosophy and understanding what a scientific theory is and the importance of a connection with empirical data, all that stuff. As a result of that book, I got invited back to attend scientific conferences again. It was quite extraordinary, after all those years, to be invited back. It’s been lovely to re-establish contact, but it’s a different community. I was a chemist—admittedly a chemical physicist, there are subtleties in all of these disciplines—but now the contacts I have are with physicists and some philosophers. It’s been a great journey. I have debated with some of them. If you look at the website of the Discovery Institute, which is the intelligent design organization based in Seattle, it’s not too difficult to track down regular blogposts about what physicists are saying about the multiverse, as a way of saying, ‘here’s an example of scientists going way beyond any evidence, and speculating about stuff and calling it science. So why isn’t intelligent design science?’ It’s a general and slow erosion. As I said, physics is supposed to be the hardest of the hard sciences, but people position themselves, with a public platform, as leading theoretical physicists, and say this stuff. The risk is then that it becomes more and more necessary to build a scientific career publishing papers that are about this stuff, and less and less about doing the hard graft and finding ways to get supporting evidence for your ideas. String theory is a good example. The momentum now is moving away from it, people are turning their backs on it, but for a time, there were more string theorists than there were physicists in 1900. And all for a structure that was basically a house of cards based on metaphysics. Nature might be like this, and it might also be like that, and then it might also be like this. You’ve got this whole structure that has absolutely no supporting evidence, and people publishing paper after paper after paper and calling it science. Science goes through these spasms, it goes through these difficult periods, but again, you’ve then got leading theoretical physicists—for a time Brian Greene was publishing bestselling books about string theory and what string theory tells us about the latest scientific thinking—when there’s absolutely no foundation for it. I’m not saying it’s the same as astrology, but I’m saying that what we look for when we do science, is we look for evidence, it’s that bringing together of evidence and ideas that makes science tick. And if it’s okay to do science without evidence—hence the notion of post-empirical science, an oxymoron—the risk is that it undermines all the arguments you have against stuff that is potentially really damaging, like the anti-vaxxer movement, like intelligent design, all of these things that can really undermine the way people are thinking about things and affect their lives in very serious ways, because the trust has gone: ‘I don’t trust big pharma, I don’t trust scientists, therefore I’m going to make up my own mind and I’m not going to vaccinate my kids.’ That’s the way the logic goes. And then you’re in big trouble. Then you’ve gone backwards. Anything that involves a computer processor of some description, so definitely your smartphone, will rely on quantum mechanics for its operation. One of my favourite examples is GPS. Do you use GPS on your phone? Do you know that GPS wouldn’t work without the special and general theories of relativity? Again, there have been arguments back and forth, but I can point you to papers that explain that without corrections—based on Einstein’s special and general theories of relativity—in the way data is reaching you from the system of six or seven satellites that you’re connected to at any one moment in time, you’d start to accumulate errors of the order of 11 km per day. So, after a couple of weeks, you could be anywhere on earth."