One of the elements of The Fabric of Reality that the art world has particularly found resonance with is the idea of multiverse.
Well the first thing to say is that the multiverse theory is only a minority opinion amongst my physics colleagues. Perhaps no more than ten percent of physicists would endorse what I am about to say. In my opinion the evidence is overwhelming that the reality we see around us—the stars, the galaxy, each other—is only one slice of a bigger reality which contains many entities of that type: the type that we call universe. So the whole collection of those entities, we call the multiverse. But as I said, many colleagues would disagree. Now, if you say artists are interested, there are two points I would like to make. One is that it is in my opinion hopeless to try to look outside the laboratory, for phenomena directly caused by the multiverse . People often ask me if dreams might give us a window into other universes, or if artistic inspiration comes from a collaboration of different instances of oneself in different universes. The answer to that is no, because the laws of quantum mechanics itself, the very theory from which we know that these things exist in the first place, says that this kind of collaboration between universes is not possible. So that’s the bad news. The good news is that the kind of reality in which we are, is one in which alternatives to the events we experience really do happen. Now, why is that important if they can’t physically affect us? My best metaphor or parable to explain why is to go back again 150 years to the time before Darwin’s theory of evolution was discovered. At that time, there was a problem: Why do giraffes have long necks? So that they can eat the leaves. But is that providential? Is it divine providence that lengthened their necks or is there some other explanation? The thing is that for most of human history, we didn’t have the conceptual framework that Darwin had to answer that question, because all theories, including theories of astronomy and so on, were about the end result. They were teleological theories, saying that the giraffe had a long neck so that it could eat the leaves or so that God would be pleased or so that it would stay alive. Similarly, even in astronomy and the other hard sciences where they had real scientific theories, they were still in the form of predicting outcome and not predicting the process. For instance, [Johannes] Kepler’s most famous law was that the planets move in ellipses with the sun at one focus. He was saying that ellipses are the answer—not circles, not parabolas, but ellipses, with the sun not at the center but at the focus. So that’s how the world is. Now starting with Galileo or Newton, the character of scientific theories changed. Instead of wanting merely descriptive theories about what the end result is, we wanted explanatory theories about what produces that result. Newton’s theory, which likewise predicts ellipses, doesn’t mention ellipses. The word doesn’t appear in Newton’s laws at all, nor does the word “planets.” Nor does the word “sun.” None of that appears. It’s a general theory, not about outcomes but about forces, momentum and so on. It’s about the thing that causes the outcome. Now we can go back to Darwin. His key philosophical innovation, the thing that distinguishes him from all previous attempts, including all previous theories of evolution like [Jean-baptiste] Lamarck’s, is that Darwin is all about the laws under which giraffes get their long neck. Again, Darwin’s theory doesn’t mention “giraffes,” “necks,” “trees,” anything like that. It’s a general theory stating what kind of a world makes a long-necked giraffe explicable, without a divine being having to create it by fiat.
That’s a toolbox.
Yes. The worldview of Newton’s physics was a toolbox that opened the door to Darwin understanding the theory of evolution. Now in the same way, I believe that the unsolved problems of the present day—such as the nature of consciousness and creativity—can only be solved within the worldview of the parallel universes. It can only be solved by somebody who knows that there are parallel copies of them, that they’re all doing different things, that the world is all connected together, just as Darwin needed the Newtonian worldview in order to understand giraffes. Note that Darwin never needed to use Newton’s actual laws of motion. He never needed to write down the formulae, the equations of Newtonian mechanics. Similarly, I don’t believe that philosophers —whatever philosophers or scientists solve the problem of consciousness — will need to use the equation of quantum mechanics. What they will need is the worldview that quantum mechanics tells us.
The concept?
Yes. The explanation. If you think in those terms you can be on the path to the answer just as Darwin had to think in terms of a Newtonian universe . If he had thought in terms of a Keplerian universe he could never have understood evolution And if we think in terms of a classical single universe cosmology like that before quantum theory, we will not be able to understand things like consciousness and knowledge. There are some examples in The Fabric of Reality of what different things such as genes, knowledge or brains look like when you look at them from a multiverse point of view. For instance, although a gene is a microscopic object in any one universe, it is a gigantic object in the multiverse. Because a gene is one of those very rare types of objects that get error- corrected back to their original form if they change or mutate. So if you have a population with a certain genome and a mutation happens, a few of them have a variant. Then if you go on through the generations, the original form will be restored because the ones with the wrong form won’t reproduce as well. That means it will get set back to the way it was in most universes.