This Changes Everything

Colin Gillespie

• Publisher: RosettaBooks
• Year: 2012
• ISBN:
  9780795332692
• Topic: Sciences biologiques
• Subtopic: Dissertations sur la science

The physicist and author investigates the 20thcentury scientific revolution that changed our lives—and how it can go further—in this provocative essay.

Much of the modern world we experience day to day has been profoundly transformed by a scientific revolution that began in the early twentieth century. But what has science done for us lately?In This Changes Everything, author and scientist Colin Gillespie suggests that the revolution has barely gotten off the ground. In fact—it's still stuck between two competing Theories of Everything.

While celebrating the victories of General Relativity and Quantum Mechanics, Gillespie attempts to uncover what holds us back from reaching even greater accomplishments. Looking at the work of physicists from Albert Einstein to Stephen Hawking and beyond, Gillespie proposes a thought experiment that leads to some startling conclusions. His provocative new take on cosmology and physics offers an elegant insight that truly changes everything.

I. Introduction

Everything that everybody relies on unthinkingly today, the entire economy, is substantially dependent upon physics that has been done in the last hundred years. Most of it is substantially dependent on physics that was done between 1905 and 1915. And there hasn’t been much of great substance done since then that effects the lives of ordinary people. That is widely regarded as an unfinished scientific revolution. It got stuck. It got stuck in two Theories of Everything. General relativity describes everything. Quantum mechanics describes everything. But they are completely contradictory. They not only don’t speak the same language—they can’t even be translated into each other.

So at least one of them is wrong. I think most physicists would say probably both, that probably each of them is an approximation of some sort—in much the same way as the physics in the days of Newton, approximated them—and that today there is brewing a new revolutionary step.

Quantum mechanics turned our view of the world upside down. If you were to take quantum mechanics out of the world today, it would collapse. Civilization as we know it would stop. The entire life of every person on the planet these days is what it is because of physics. Physics has transformed our lives: past tense. Physics today continues to transform our lives: present tense. Physics will continue to transform our lives, whatever happens to it: future tense. And yet it’s something that not only do most of us think we have no say in, but we don’t even think we can grasp what it is to have a say. I don’t think that’s right, but to demonstrate how it’s not right, to make it different, requires that people have two things. One is the confidence that we can, so that we try—and secondly, the common language so that when we try, we find that we actually can have a say.

Let me give an example. Most people conceive of space—if they think of it at all, and many don’t—as infinite. I would bet that if you lined up a hundred physicists, ninety of them would say they agree that space is infinite. Well, space isn’t infinite, if I am right about any of this. It comes in tiny pieces and there is a finite, exact number of pieces of space at any given instant. It increases because they tend to split into two pieces; that’s why space is still expanding. But it’s a number. And you can write it down on a sheet of paper without having to cramp your handwriting. It’s a big number but not an impossibly big number.

Space is vast enough that even with a Hubble telescope you can’t see all of it, because there hasn’t been enough time for the light to get here from everywhere in space. But it is finite. Well that’s a whole different notion. When you add to that that every atom in you, and every piece of every atom in you, is directly connected to every one of those pieces of space, you’ve got a different concept of yourself and your place in the world. Maybe in somewhat the same sense as when people first saw that blue earth rising over the moon—it just gave people a different perspective on things. I think that kind of stuff matters in people’s lives.

II. Hail the heroes, unsung and otherwise

The physics story is a history of an unfinished scientific revolution that has changed everybody’s lives but hasn’t finished doing that job. The missing part is simply the final steps of coming to grips with the reality of the universe as it is. Science—physics in particular—knows that it hasn’t got there and doesn’t yet know how it can.

The only place to start a Theory of Everything is at everything’s beginning. I don’t think you’d have a tough job persuading most physicists of that. It is curious that most physicists nonetheless either haven’t gone looking at all or haven’t gone looking there. The reason isn’t all that hard to find. It goes back to the deep divide between religion and physics. Physicists break out in a rash at the notion of anything that they are doing or thinking about doing coming anywhere close to religion. And their instinct is that a beginning to the universe has got to be something to do with religion.

Now this has been inflamed, accidentally as it turns out, by historical circumstance, right after 1915 when Einstein published his equations of general relativity, which I would just note were in themselves setting out a Theory of Everything (although they didn’t turn out to entirely work that way). The current model of the universe came from a solution of those equations by Georges Lemaître. He was a Belgian physicist who was also a priest, and that’s a combination of roles that has colored cosmology ever since.

You might say that Lemaître invented cosmology—with a little help from Einstein in 1917, who wrote the first serious paper on it—but Lemaître was widely viewed as having a religious agenda. I think that’s not accurate, but his agenda wasn’t seriously examined until quite recently. And those who did examine it came to the conclusion that the accusation was not in fact true.

But what happened was very curious. Lemaître became, and still is recognized as, the father of the Big Bang theory. His solution of the equations showed an expanding universe. Einstein virtually disowned him because he didn’t like that solution. It wasn’t until Edwin Hubble’s experimental observations, which confirmed it, that Einstein backed down. The equations for what happened after the beginning have become the standard fare of cosmology and indeed these days of astronomy. Everyone knows the universe began with a big bang. Well, actually, it didn’t. That, too, I would think all physicists would agree with. They realize that there was something different about the very beginning. Now, Lemaître got to it by the simple device of running his equations backwards. And you can do that with physics equations; just run time backwards and they oblige. If you run the equations for an expanding universe backwards, what you find is that everything finishes up at a single point, at some single instant in time. Einstein would have been the first to say that his equations in general relativity certainly do not describe that. He would be the first to reach for a quantum theory and to say that, with anything that small, that peculiar, you need to look at it at a quantum level. So what we are left with today is that the beginning is unexplored, and has been attributed to Georges Lemaître the priest, and is consequently out of bounds. And everything after that has become mainstream, and is physics, and is attributed to Georges Lemaître the physicist.

Face to face with Einstein

I think there’s a lot to be re-appreciated about Einstein, and this is not something that is new; there’ve been a lot of people studying Einstein’s works, his correspondence, his life.

The first thing to note about Einstein is that he was the originator of essentially all of twentieth century physics. Not just the pieces that he is famous for—he wrote five papers in 1905, not just the one on special relativity, and each one of them generated a completely new field of physics. He was an extraordinarily prolific source of ideas. He was also an extraordinarily prolific source of changing his mind. He joked about it. He said, ‘I make my living saying something this year and then saying the opposite next year.’ Which is strikingly true. The other thing about Einstein was that he was a public figure. In 1915, when his obscure predictions about the behaviour of light in space were confirmed by the observation of an eclipse and the news was splashed across the world, he wasn’t the world’s most famous scientist—he was the world’s only famous scientist. And in some sense, he still is.

Historically, Einstein was a positivist. He lived in the age of positivism and this was a Germanic kind of philosophy—suited to the times, suited to the country. Germany, in that era, was the source of essentially all physics. The world of physics moved in a very positivist philosophic fashion. In its most extreme manifestation this says we’re not sure there is any reality there, but what we want to do is be able to calculate things and predict what this atom may be doing in ten seconds time. So, ‘shut up and calculate.’ Most physicists today finish up with the degree, as I did, of Doctor of Philosophy, without ever studying a single course of philosophy. But in their physics, they imbibe, they inhale positivism, as a philosophy. So they finish up as positivists without even necessarily being able to spell it.

Einstein, on the other hand, became a realist in his later days. He moved to the concept that the role of physics is to understand the world that really is there and that a theory in physics was to be tested against that reality and against its ability to explain that reality, to lead to an understanding of that reality. That’s a very unpopular view of physics today, and it was in his time. Let’s put it this way, it’s probably the popular view on the street; that’s what they think the physicists are doing, but that’s not what the physicists think they are doing. They don’t think they’re explaining or understanding anything. In fact when they get together they sometimes have a couple of drinks and confess that they don’t understand anything anymore. Which is not as bad as it sounds, because that’s not their job anyway.

So that was a transformative change in Einstein that is relatively unknown other than to students of the history of science, because he didn’t actually produce a great deal that got noticed in that latter period. But what Einstein did that really needs re-examination, above all, is that Einstein was the last great practitioner of the transformative effect of philosophy on physics. He did it. His physics derived directly from his philosophy. You can malign his philosophy, but he made the connection, he saw it that way. That’s the way it was supposed to be, and we’ve lost that. And guess what: without that, it doesn’t work the way it did when it kicked off the scientific revolution.

There is a lot that is not in public view about how Einstein transformed physics. Even today, you can’t take hold of almost anything and dig into it in any depth without finding that you are face to face with Einstein. And secondly, it’s not just the tablets being brought forth down the mountain; he had doubts; he constantly was questioning everything. He built his entire career and fame on partial differential equations, and yet in the Fifties you find him writing to a friend and saying that he thinks they are wrong. He doesn’t think the universe is like that at all. He says, I think that space is really made of little pieces, but I can’t do the math; it’s driving me crazy.

Copenhagen v. David Bohm

To me, the contribution that David Bohm made that matters needs to be set against the quantum mechanical interpretation that became known as the Copenhagen interpretation, which is what is widely imbibed by physicists. And which, again, needs to be seen in its context of intense nationalism and political turmoil in 1920s Europe and in Germany in particular. It was projected to the world, to the physicists of the day, vociferously, as the right picture—as not just right but inevitable, as something to which there not only was not but never could be any coherent alternative. ‘This is the way we must think of things at the atomic level,’ which is what they were focused on.

This led to ‘shut up and calculate’. More precisely, this was the ‘shut up’ that led to the ‘calculate.’ And it was very successful because the calculating worked. And trying to buck the ‘shut up,’ as David Bohm showed, didn’t work worth a damn. But he tried, and what he did was quite astonishing.

He was not in any sense antagonistic to conventional quantum mechanics—in fact he wrote the standard text of the day, Quantum Mechanics. But he became persuaded after having met Einstein at Princeton, where he was working, that there was something incomplete about quantum mechanics, which was somewhat of an obsession of Einstein’s (one which turned out to be wrong, but this wasn’t clear until decades later, when Bell’s theorem was vindicated by experiments.)

So you have Einstein as the voice in the wilderness, sidelined in Princeton, chatting with his friend David Bohm, who becomes intellectually persuaded that there’s something here, and he comes up with an alternative. And really that’s his contribution. It’s not the only possible alternative, but he showed that an alternative was possible, and that it was as good as quantum mechanics. It led to exactly the same results—which of course led all the quantum mechanists to say, ‘Well, if it gives the same results, why should we bother using it? We learned it this way, why would we want to spend a bunch of time learning it a different way to get the same results? It doesn’t make sense.’

But what did make sense was the interpretation. His alternative concept of atomic physics, and of what was going on behind the scenes of an atom, the behaviour of electrons, made more sense. Which wasn’t difficult. Quantum mechanics makes no sense. It just works. Niels Bohr, who played a central role in developing the whole field of the Copenhagen interpretation, himself struggled desperately to understand it; but in the end, having failed, he subscribed to and was maybe the central mover of the notion that the reason that they failed to understand it is that there is nothing to understand. Literally. As in: ‘You don’t understand where the electron is between here, where we measure it, and over there, where we later measure it—you don’t understand where it went because it behaves as if it went both this way and that. And the reason is because actually it wasn’t anywhere; there is no such thing as the position of the electron between measurements.’ Heisenberg not only signed up to that idea, but he expanded it with his Uncertainty Principle, and it has become conventional physics today. That’s what graduate students are taught.

I don’t think anybody has shown that, from a physics perspective, Bohm’s theory is superior to conventional quantum mechanics, and I don’t imagine that they will. Rather, to me at least, what Bohm did was put another marker on the scene, and said there isn’t just one interpretation, there are at least two. And once he had broken down that barricade, one could imagine that there may be other ways of conceptualizing what we call quantum theory.

Bell’s Theorem

It’s not widely known that what John Bell did was completely extracurricular. He worked at CERN, and he was very offended by the way that David Bohm had been treated. (He was very badly treated, and not just by the physics world. He was run out of his profession, he was run out of the country, and he died in very unfortunate circumstances.) And that led Bell into a similar kind of avenue, of questioning quantum mechanics, and questioning this war of ideas that had gone on for a half a century between Einstein and his colleagues and Bohr and his colleagues.

Bell devised an approach, really an experiment, that came to be known as Bell’s Theorem. He said if you do this kind of experiment and do it often enough and check how many times you get this result and how many times you get that result, there are two ways it can go: If it goes this way, it means Einstein is right, and if it goes that way, then Bohr is right. He was the first to devise a way of telling which was right, and some years later the experimentalists started to get a handle on doing that kind of experiment. It’s been done a number of times since, and they always come back with the same result, and the results say that Bohr was right, Einstein was wrong. There is not what Einstein called, and what came to be known as, a hidden variable—something that’s there but that quantum mechanics is not addressing. Put in another way, the results say quantum mechanics is a complete description of the physics of that kind of experiment—something that Einstein never accepted.

This situation is like Plato’s allegory of the cave. You’ve got the physicists chained there, looking at the wall, and all they see is shadows. They’re seeing shadows cast from the world, from the atom for example. And one or the other interprets them in different ways, and none of them is right but none of them is wrong. All of them are intellectually held back from seeing or even conceptualizing what it is that is really there.

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