I. One Small Step For Science
What is theoretical physics? Broadly, it uses mathematics to understand and predict our universe. Sadly, for a great number of people that’s a scary thing. And I understand why: As you look deeper, it doesn’t take long for a handful of equations to become so complicated that they may as well be written in a language of forgotten runes describing some ancient ritual. At this level it can seem completely removed from our lives. Yet it is this complexity, or rather the logic from which this complexity is derived, that allows us to understand the universe as it is and predict how it will change. Isaac Asimov explores precisely this in his Foundation series through the character Hari Seldon who creates a field of science, psychohistory, that reduces destiny down into a set of equations with which he predicts the rise and fall of the human race. The books themselves focus on various characters who are following the path laid down by Seldon, a figure who becomes messianic to Asimov’s futuristic society.
Asimov’s story may seem ridiculous but we can see how much genuine faith has been put into science and mathematics from projects such as the Apollo space program. The flight journal of Apollo 8, which was the very first human spaceflight to escape the Earth’s gravity, contains a wonderful interaction between Michael Collins, who was working at Ground Control, and astronaut William Anders on his way back from the Moon:
Collins: I told Michael you guys are up there, and he said who’s driving?
Anders: That’s a good question… I think Isaac Newton is doing most of the driving right now.
Collins: We copy.
Anders: Well, give Valerie and the kids a Merry Christmas for me, Mike. And tell them I’ll see them there in a while.
These space missions sent squishy humans tumbling through the wildly dangerous conditions of outer space with Newton’s equations of gravity to guide them. The gamble that’s been made here cannot be overstated. NASA was resolutely confident that science would keep their astronauts safe, get them through unknown waters, and bring them home.
Newton might have discovered the equations of gravity, but it was Frances Northcott and her team who developed the flight plan to bring Apollo 8 back to Earth. A woman whose boots remained firmly on our planet was able to fly a spacecraft 380,000 kilometres away from Earth and back. This incredible feat is possible because of her ability to use mathematics and her understanding of the laws of physics. But how is it possible for mathematics to take us so far from the only world we know? On an individual level it acts like an extension of our senses. By this I mean that although we can experience something with a sense, numbers allow us to then quantify its character, and with geometry we can capture its form. In this way a forest can be recontextualised as 500 trees and the Moon as a sphere of grey rock. I should say that this discussion is a veritable can of philosophical worms, at the bottom of which is a lengthy debate about a concept called phenomenology, which is perhaps the biggest worm of all. We don’t want to concern ourselves with it, so we’ll just open the can slightly to say that when we are attempting to understand something, we are conceptualising and replicating it within our own minds. We call this a theoretical model. It acts as a kind of dream in which the physics of our own world can be replicated. Importantly, this dream isn’t static. It can be adapted, transformed, or entirely replaced with something else. We can test it by comparing the expectations it gives us with realities of the thing we are trying to understand. This is how we can discover new features of reality or, as with Apollo 8, venture to places we haven’t been. And so, in some ways, Northcott was one of the first people to travel to the Moon, which she did in a dream of mathematics.
It’s funny, isn’t it? How a different way of thinking has allowed a community of apes to travel into space and, with the laser, create a type of light that is capable of cutting through steel. The pure absurdity of our situation is something we can derive a great deal of humour from, which is particularly important in a universe brimming with things that nobody fully understands. A very sensible reaction to all of this is to feel insignificant and overwhelmed, but we must fight against that urge. Not only is it depressing but it misses the point: Although we may not know the definitive truth of life, the universe, and everything, we are moving closer towards it. Every moment of learning is a moment of humanity pushing a vast and dark sea of mystery back. Crucially, each time we push, a simultaneous transformation occurs within us: This is a genuine moment of enlightenment. Between the prehistoric and the modern ages these moments are strung together like a daisy chain. Each must have provoked an intense wonder upon their creation, a feeling that can be difficult to understand from a long distance of kilometres and years. One of the exceptions to this is fire which, in contrast to the comfort of our modern homes filled with electrical light and heat, can still fill us with a sense of primal wonder.
I. One Giant Leap For Everyone
If we were to draw the journey of theoretical physics on the map of history, the path of science from fire to photons would not be a simple straight line from ignorance to enlightenment. This contrasts heavily against what I was taught at school: That each scientific discovery effortlessly led to the next, and the truth seems to blossom like an ever-blooming flower. Not only is that picture wrong, it’s completely dishonest! My experiences as a researcher have convinced me that the reality is closer to something imagined by British philosopher Karl Popper. Popper proposed that science is powerful because it is open to being wrong. Think of it this way: in the barest terms every scientific theory is simply a guess because nobody can ever really know the ultimate truth of the universe. But a scientific theory is particularly special because it’s a guess made with the knowledge that a better one could come along and replace it. In this sense, every theory is a failure-in-waiting. Despite those failures, or rather because of them, we move towards something that appears to be more true. So by focusing on a single thread of famous theories that tracks scientific progress through the ages rather than the errors, missteps, and outright catastrophes, we miss the point of it all! We should instead envision something more complicated; an unravelled tangle of stories that pictures scientific progress and its failures like a river and its tributaries.
This sprawling model of science is reflected in the education of physics students who are taught several different definitions of light. Each originates from a different era and a different point in the scientific tradition, and therefore each operates under the logic of a different philosophy. Yet somehow, all these interpretations seem to happily coexist in a beautiful mess. I can show in gruesome detail just how the sausage gets made by sharing my own experiences of this: By the time I’d finished secondary school I thought I had a good understanding of light: It moved through the world as a ray, straight line after straight line, bounding across mirrors and through glass. This was represented by the problems I found in my CGP textbooks. Solving them was a matter of using trigonometry and applying something called Snell’s Law. Then, at university, I was confronted with my naivety by the prevailing truths of our brilliant and wild reality. My electrodynamics lecturer introduced me to light’s relationship with electricity and magnetism, all elegantly described by what are known as Maxwell’s Equations. Because of the pictures they painted, I began to imagine invisible electromagnetic fields silently communicating in a language of unseen light. I then learned about the photon and how it obeyed alien laws of physics. This was my first encounter with quantum mechanics. With it everything solid became translucent and ill-defined. It sounds magical but within days, maybe even hours, those revelations became new problems in new textbooks. Wonder was replaced with applied calculus, because without mathematics modern physics is science-fiction.
My perspective of science was flipped upside down after watching the documentary series Ascent of Man presented by Jacob Bronowski. It traces the development of scientific thought from deep history through to the 20th Century. Bronowski himself was a towering figure of science. He worked on the Manhattan Project alongside a number of other brilliant minds whose fame now haunts modern theoretical physics. Following his research on the atomic bomb, that infamous creation of supreme violence, Bronowski decided to instead apply his skills as a theoretical physicist on the gentle task of understanding Humanity’s place in the wider web of life on Earth. It is from this place of existential reflection that Ascent emerges. The documentary confidently abandons spectacle for the quiet joy of an intellectual journey by focusing on the relationship between the human mind and the world around it. I was struck most powerfully during a particular monologue where Bronowski states:
“The notion of discovering an underlying order in matter is Man’s basic concept for exploring Nature. The architecture of things reveals a structure of things below the surface. A hidden grain which, when it’s laid bare, makes it possible to take natural formations apart and assemble them in new arrangements.”
In other words, the only way any of us can figure out what something is or how it works is by bending and breaking it. Children do exactly this when they fiddle and play with whatever catches their eye and captures their curiosity. Scientists are similar, some of them spend their careers smashing protons together in a particle accelerator and then sift through the pieces that are left. Both are examples of discovery and, as Bronowski succinctly describes, both originate from the same human impulse. This hidden grain not only underpins all scientific ways of thinking but also applies to those older forms of critical thinking that precede our relatively modern concept of science. This is the spirit of science. An ancient and silent tradition of creative exploration where the world is remade time and time again. It is the tradition of natural philosophy, as familiar to Socrates as it is to any modern physicist, and it is old as fire.
What we can take away from this realisation is that science, and by extension theoretical physics, doesn’t belong to scientists alone. It belongs to everyone because it is a product of the human spirit. The same inventive minds of prehistory that crafted arrowheads out of flint and obsidian are now those that work to replicate the power of the Sun inside a fusion reactor. Isn’t that incredible? They’re also the same minds that write screenplays, build houses, play football, bake bread, dance, sing, eat, laugh and every other thing that constitutes human life on Earth. We all carry that creative flame within us. So we must respect perspectives shared by those who are not scientists, and include them when we discuss science. This becomes evident when we consider that scientists cannot exist without society’s support, from public funding for their research project to their rubbish being collected. Science requires everyone to pitch in. So although it might scare you, I encourage you to embrace the strange and the mathematical.