This is Part 2 in a series on the mathematical universe hypothesis. Check out Part 1.
Like, it shouldn’t be this easy. Yeah I know physics is kind of hard, and it has taken us centuries to reach our present level of knowledge, and we know we’re still a long way from complete knowledge of time and space. But on the other hand, look at all the technological marvels that fill our lives. The smartphones and GPS satellites and cures for diseases. We have all that STUFF because of science, and science works because math is just so dang handy at describing the universe.
We did natural philosophy for thousands of years. And we made progress, for sure. But once we started using math, it seems like there are new revelations every single day…because there are.
WHY is math so good?
Maybe math isn’t just a description of nature. Maybe math IS nature. And the reason it’s so good at its job is because we finally, after millennia of attempts, hit upon the secret language of nature, just like Galileo said.
Maybe the universe is made of math.
The latest version of this idea comes to us from cosmologist Max Tegmark. I wouldn’t exactly call him a friend of mine – we don’t hang out often enough – but definitely somewhere on the colleague/acquaintance spectrum. Anyway, back in 2014 Max wrote a book, Our Mathematical Universe, which outlined this philosophy. Now the line between physics, metaphysics, and philosophy is often blurry. In the book Max claims that his idea is physics: it makes testable predictions. To me, and I know I’m showing my bias here so please judge for yourself when I talk about it later, those claims aren’t all that strong, which would put the following discussion in the metaphysics category.
Which is fine. There’s nothing wrong with metaphysics. Philosophy is useful and important and worth debating and exploring.
So let’s dig in to what ol’ Max Tegmark has to say about the universe.
Let’s start with assumption. It’s a big one, and a debatable one, but we’re going to say it out loud and move on: that there is an external, objective reality (as in, we’re not making up reality in our minds, and it exists independently of us conscious observers). The whole process of science is to discover and explain that external, objective reality, and we’ve been using math very successfully to do just that.
But there’s more to science than math. There are words and concepts and ideas that are very, very human. We might have some beautiful mathematical theory (like GR or quantum mechanics) but then we also have a bunch of human-concocted concepts to wrap around the math, like wave function and spacetime and equivalence principle, and even mass and charge and force.
Tegmark argues that all this is “baggage.” It’s a layer of our subjective human-centered view of the universe that sits on top of the real deal, the math itself. So we need to apply Occam’s razor: make our perspectives as simple as possible. We need to dump all the baggage overboard, because it’s just getting in the way. The REAL structure of reality will not have any baggage. That’s created by us subjective humans. External, objective reality is baggage-free, streamlined, efficient, straightforward.
And what happens when you strip out all the baggage from our theories of physics? Bare, raw math.
This isn’t Occam’s razor. It’s Occam’s sledgehammer.
Tegmark is saying that math is more than a useful tool to study the universe. He’s saying that once we get down to brass tacks, it’s just math.
Take a chair. Strip away the baggage. The color. The mass. The atoms. The forces. Once you remove all human-derived concepts, you’re left with…relationships. Symmetries. Structures.
You’re left with math. Math IS the universe, and the universe IS math. There’s no distinction, no difference between them.
If we work at physics hard enough, then math won’t just reveal the universe to us, the universe will be revealed as even more math. Some physicists are on a hunt for a “theory of everything”, a single unified theory that describes all the forces of nature. Tegmark says that if he’s right, then this theory of everything wouldn’t stop there, it would also explain all the kinds of particles, all their possible interactions, and all the properties of the universe.
You know how I did that episode a while ago on the constants of nature? Yeah, a proper TOE wouldn’t have ANY constants: no speed of light, no charge on the electron. Not even the number of space and time dimensions. It would be a single equation (ok maybe a set of equations) that explains ALL of reality (including itself! which is kind of wild to think about if you’re into that sort of thing).
And because that single mathematical equation could describe all of reality, why don’t we just cut out the middleman and say that the mathematical equation IS all of reality? I mean, Occam’s razor, right? Why make things more complicated?