Toy soldiers and four dogs

Sabine Hossenfelder interview with Garrett Lisi

“Why are you so convinced there is a theory of everything?” I ask.

“What we have now with the standard model, it’s a mess,” Garret says. “We have the [mixing matrices], and the masses - we have all these parameters. I’m of the opinion that all these pseudorandom parameters have an underlying explanation that will lead to a unified underlying theory.”

“What’s wrong with random parameters? Why does it have to be simple?”

“Well, as we’ve gone down in distance scales it’s always become simpler,” Garrett argues. “You start with chemistry, and the substances, they have all these these scattered properties. But the underlying elements are pretty simple. And if you look at shorter distances, inside the atom, it gets even simpler. Now we have the standard model, which seems to be a complete set of particles and gauge bosons. And with what I have done, I think I have a good geometric description of the fermions. It looks like it’s all one thing. To me, that’s just extrapolating the path of science. Things seem to look simpler if we look at smaller scales.”

“That’s because you conveniently started with chemistry,” I say. “If you start at a larger scale, the scale of, say galaxies, and go down, it doesn’t get simpler - it first gets more complicated, as with life crawling around planets and all that. It’s only past the level of biochemistry that it starts getting simpler again.”

“Ah, it can’t be like that,” Garrett says. “We know the elementary particles can’t be like planets. We know they are exactly identical.”

“There’s no such thing as ‘exactly’ - it’s always to some limited precision,” I point out. “But I don’t mean that elementary particles are like planets,” I explain. “Just that, whatever is the theory at short distances, it might not be simpler than what we have now. Simplicity doesn’t always increase with resolution.”

“Yes, it could be a mess,” Garrett agrees. “Or it could be that there is some underlying framework that we’ll never have experimental access to, and all we can see is this mess that sits on top of it. Xiao-Gang Wen, for example, he likes to say that the laws of nature are fundamentally ugly. But this is an idea that’s abhorrent to me. I think there is a simple, unified description that will explain all phenomena.”

I make a note to contact Xiao-Gang Wen.

Excerpt from Lost in Math - how beauty lead physics astray
Sabine Hossenfelder

(Basic Books, June 2020, pp167-8)