This episode of Rationally Speaking is brought to you by Stripe.

Stripe builds economic infrastructure for the Internet.

Their tools help online businesses with everything from incorporation and getting started

to handling marketplace payments to preventing fraud.

Stripe's culture puts a special emphasis on rigorous thinking and intellectual curiosity.

So if you enjoy podcasts like this one,

and you're interested in what Stripe does, I'd recommend you check them out. They're always hiring.

Learn more at Stripe.com. Welcome to Rationally Speaking, the podcast where we explore the borderlands between reason and nonsense.

I'm your host, Julia Galeith, and I'm here with today's guest, Sabina Hostenfelder.

Sabina is a theoretical physicist focusing on quantum gravity.

She's a research fellow at the Frankfurt Institute for Advanced Studies and blogs at Backreaction.

And she just published the book Lost in Math, How Beauty Leads Physics Astray.

Lost in Math argues that physicists in at least certain subfields

evaluate theories based heavily on aesthetics. Like, is this theory beautiful? Instead of simply,

what does the evidence suggest is true. And the book is full of interviews Sabina did with top

physicists where she tries to ask them, what's the justification

for this? Why should we expect beauty to be a good guide to truth? And spoiler alert, ultimately

she comes away rather unsatisfied with the answers. So we're going to talk about lost in math

and the case for and against beauty in physics. Sabina, welcome to the show.

Hello. So first, probably best to start with, what do you mean by beauty in this context?

Is it, and is it closer to, you know, a kind of beauty is in the eye of the beholder thing? Like,

every physicist has their own sort of aesthetic sense? Or is it more like there's a consensus among physicists about, you know,

...