To solve the big mysteries in physics, we need to embrace fresh perspectives, says cosmologist Stephon Alexander. Here he explains why intuition is so important – and outlines one of his own wild ideas
AS A child, Stephon Alexander was awestruck by the broken-down, graffiti-covered train carriages in the depot opposite where he waited for the yellow school bus each morning. Graffiti artists were his heroes, as were urban philosophers. Later, he joined a hip-hop group. “I used to beatbox in rap battles. They called it dropping science too,” he says.
Growing up in the Bronx in New York City in the 1980s might not be the typical training for a theoretical physicist, but it helped shape Alexander’s distinct style. “That collision of all these different cultures was valued because we saw the product,” he says. Alexander learned to embrace the discomfort of difference and saw the ideas that sprung from it. But as a young Black scientist, he was snubbed by colleagues. His speculative ideas were deemed outlandish by some of his peers.
Alexander sought refuge in jazz clubs, cafes and Zen Buddhist centres. Making friends with biologists, musicians and artists, he forged his own approach to the big questions about the nature of reality – one that valued diverse viewpoints, intuition and imagination.
Today, Alexander is a cosmologist, string theorist and jazz musician. He heads a research lab at Brown University in Providence, Rhode Island, seeking to unite the smallest and largest entities in the cosmos and unearth what came before the big bang. He is also president of the National Society of Black Physicists.
In his new book, Fear of a Black Universe: An outsider’s guide to the future of physics, Alexander argues that welcoming new voices into the “club of physics” will be essential to breaking new ground. Scientists could learn a lot from graffiti artists, once regarded as vandals but now revered by the art establishment, he says. “They recognise that it’s important to keep a foot on the outside and to keep on talking to others. It’s at that interface that we can expect new innovations to come,” he says. In this way, he hopes off-road thinking can put physicists back on the right track.
Thomas Lewton: Alongside theoretical physicist Lee Smolin, virtual reality pioneer Jaron Lanier and others, you recently proposed that the universe learned its own laws in the same way that artificially intelligent neural networks teach themselves. What is the appeal of a self-learning universe?
Stephon Alexander: I’ve asked the why question throughout my career: why is our universe special? String theory tells us something about how the laws of nature emerge. You start out with a string – there’s no gravity or particle physics – but then these forms and forces appear. But string theory doesn’t answer the why question. It lacks a mechanism to select which of the slot machine of 10500 possible universes is our universe.
If the forces in our universe were slightly different, then stars wouldn’t be able to burn hydrogen. You couldn’t make carbon, and if you can’t make carbon, then where are we? Why are the laws as we see them today? So we’re trying to come at this another way. A self-learning universe provides a mechanism to select those laws.
How could the universe be self-learning?
Learning is accumulating information and then making decisions based on this. It also needs some kind of stability; it must build and be sustained through time. So you start off with a set of very simple primordial rules, which are also a set of learning rules. These are prior to the laws of nature. If the rules can learn some of the laws we now know exist, like the laws of gravity, that’s a good learning system.
We have the universe of learning architectures and machine learning and artificial intelligence. And then, in the other universe, we have the laws of physics as we know them. It’s two sides of the same coin.
Which fundamental laws might have a learning architecture built in?
“Matrix models” are one example. You can picture these as chequerboards with different colours in each square that are constantly changing. Each matrix can have billions of columns and rows. Let’s assume this matrix theory is the mother of all theories, that it contains all possible laws. How does it realise the specific laws necessary for our world?
The mathematics of matrix theory seems to have some of the ingredients of a particular type of neural network. The idea then is to show that at least one of these neural network architectures can learn one of those laws. That correspondence would be an indicator. That’s what’s wild and beautiful about this idea, because if that’s nature at its most fundamental, then nature itself is like a neural network.
Wouldn’t it be a leap to go from this correspondence between the laws of physics, matrix theory and neural networks to then saying that the universe actually is a neural network?
It is a leap. It would be analogous to a neural network. We’re still playing with the idea, and it might end up taking us in another direction.
It also wouldn’t necessarily mean a neural network in the sense of a hardwired computer. A computer is just the substrate for neural networks. There could be something more biological going on. The universe itself produced brains, so why couldn’t the universe itself be a superbrain?
If you find enough of these correspondences, would we have to consider neural networks to be as “real” as physical laws?
I think we would have to. It would be real in the same way that we think electric or magnetic fields are real. Or think about when Paul Dirac predicted antimatter. You have a mathematical equation that seems to say something absurd about reality – that antimatter exists – and it then turned out to be a hidden part of reality.
How does a self-learning universe differ from an evolving universe?
Evolution depends on the idea of fitness within an environment. In evolution, species get killed off. In the same way, an evolving universe depends on there being a large population of universes and only the fittest ones – say with the right constants of nature – will survive.
Learning means that you have an opportunity to make a mistake without getting wiped out. These matrix models have a lot of space in which to store information. So you store that mistake as a memory and keep moving forward. It’s akin to jazz improvisation.
Why are bold ideas like this such an important part of doing physics?
I’m this kind of physicist who thinks these wild ideas. I even have ideas that I’m afraid to tell for fear of not being taking seriously or respected as a physicist. It certainly doesn’t help that I’m Black, and the biases and presumptions that go with that.
“The universe produced brains, so why couldn’t the universe itself be a superbrain?”
I went into this book asking: why do I do physics this way? Then I realised Max Planck thought consciousness subsumes everything. That Niels Bohr was studying Confucianism and Taoism. Then, wait a minute: Wolfgang Pauli was doing dream analysis?
It’s good for the advance of science. History has proven that to be the case. You need it all, because we’re dealing with the unknown. We’re dealing with nature that’s much smarter than we could ever be.
In your new book, Fear of a Black Universe, you write about the “club of physics”. What is that?
We form groups, we form social bonds, and I don’t think scientists are devoid or excused from that. These bonds are surrounded by certain social forces that can penalise or benefit you. It’s a very human thing.
There’s also an intellectual confidence and arrogance that makes physics hard for some people. We live in a Western society where people of colour and women have been stereotyped to be lazy or emotional or less intellectually endowed. I have my own personal experience of it. This is not saying: “Oh, give me a pass, because I’m suffering.” It’s actually the exact opposite. If you’re not fitting in, you’ve got to work hard.
Who introduced you to physics?
My high-school teacher Mr Kaplan told me that “intuition is the lifeblood of a great physicist”. It’s Einstein’s thought experiments, it’s Schrodinger’s cat. We intuit first, then confirm with math.
In my first physics lesson with Mr Kaplan, I didn’t know a damn thing about physics. But from watching him throw a ball up and down, I intuited the conservation of energy. That opened up my eyes that I could do physics. You don’t have to be some genius. It’s a human thing, it’s our birthright.
A revolution in theoretical physics – akin to the discovery of general relativity or quantum mechanics – seems long overdue. Do you attribute this to an unwillingness to embrace people from a variety of backgrounds?
I’m going to put my sword in the ground and say yes. I’m not saying we should just bring everyone in and [sing] Kumbaya. But we should look into this and empower those who are doing good work.
Given how deeply mathematical theoretical physics has become, do you think that makes it harder to apply intuitive thinking?
It does make it harder, but that’s why these things should be done collaboratively. Some people might play the role of being speculative while the others are more grounded. By the way, that’s what happens in jazz improvisation. When you’re improvising your solo, you’re exploring, but it’s kind of weird if there’s no background band supporting that. Then everyone else takes their turn to solo. We need both the grounding and the exploration.
How do you improvise when doing physics?
My intellectual training has not just been learning mathematics and the concepts of physics, but also learning philosophy.
You still need those mathematical tools. You need to find yourself within the tradition of physics. I believe in experiments. But you also need to explore wild ideas and be brave. You need to talk to others who you’ve been taught not to respect. They might have something to teach you.
I’ve had the fortune to train with Zen masters. I also trained in dream analysis with [theoretical physicist] Chris Isham. That’s where a lot of the magic started to happen. It’s like the Zen proverb of emptying your cup. How do you empty your mind so that it can contain new ideas? Ideas are going to come from irrational, illogical places sometimes.
“Koans” are these Buddhist riddles and paradoxes that are thrown at you. My entire life, as a physicist, I’ve trained my mind to be mathematical and to think logically. But you can’t get insight into these koans with that kind of thinking. It’s before thinking. The creativity in physics also lives in that place. For many years, I didn’t talk about any of this.
So what initially seems implausible can actually turn out to be what reality is deep down?
Absolutely. Take quantum mechanics: a particle can be a wave and a particle. But our experiences of waves and particles seemed to be separate. It’s an impossibility that then became a reality. Or look at the new interface between consciousness, physics and artificial intelligence. Scientists are writing papers about it. We’re now embracing what was once thought to be absurd.
In your book, you write about how Bantu-Kongo philosophies have led you to new ideas about quantum cosmology.
I was talking about my craft with the legendary bassist Melvin Gibbs, and afterwards he sent me a book about African cosmology. I realised that some elements of the origin story of the Bantu-Kongo people of West Africa fit very nicely into a problem in quantum cosmology.
Quantum cosmology is about applying the laws of quantum mechanics to the entire universe. Stephen Hawking and James Hartle came up with this idea of the wave function of the entire universe: that the entire universe is a quantum-mechanical system containing the potential of all things.
If you accept this, then you have to deal with the measurement problem. If there are no observers out there to measure the wave function of the universe and so collapse it, what do you do about that? The idea is that the universe observes itself. But how does it observe itself? Well, if there’s some form of protoconsciousness associated with this wave function, then that observer doesn’t have to be at a specific point in space. The observer is non-local. But through that observation, the universe disintegrates into local observers.
This is a Bantu-Kongo idea called mbungi. In the state of mbungi, both physical and conscious awareness are complementary. They are a duality – just like wave-particle duality in quantum mechanics, where a particle is a localised version of a non-local wave.
How can physics welcome people from a wide range of backgrounds while still embracing their differences?
I’ve created a group for young Black theoretical physicists and scientists called NeXus. There are still so few Black theoretical physicists. In my time, when I was a postdoc, there was only me and somebody else around the globe.
The idea is, everybody is a different kind of theorist. We have researchers in quantum gravity and machine learning, we have black hole physicists and theoretical biologists. They meet to share techniques and to do research projects together. And when they meet, they’re all thrown out of their comfort zones.
We need to embrace discomfort. If you are hiking up a mountain and you are uncomfortable, are you just going to hike back down? If you hear a different way of thinking about something, what are you afraid of? That’s Fear of a Black Universe.
Author: Thomas Lewton
SOURCE: Newsscientist