Is the universe intrinsically random? In this conversation, we dive deep into why the universe may be fundamentally intrinsically random. Whether inflation is on life support, the truth behind the Hubble tension, and whether cosmology is approaching the event horizon, the limits beyond which humans can never know. Today, we're joined by one of the architects of modern cosmological inference, Professor Andrew Jaffe, author of a new book called the Random Universe, that. That argues that every observation in science is shaped by the models we bring to it, biases and all. So what's one model, or personal belief that you held for years and years and years and then later only discovered that you were completely wrong?

Oh, gosh, let's see. What did I, what did I think I was wrong at? Well, almost nothing. No, if only that were true. But, I mean, there's. So there's lots of different realms I could go into. I guess many. The ones where I find myself off wrong the most often are probably interpersonal relations. So we all build models not only of just the physical world around us, but the people around us all the time.

And I suppose, you know, you, you're in relationship with people, friends, enemies that become friends. I mean, that's a great, That's a great example. When you thought you understood somebody and you thought that they were diametrically opposed to you in some ways or other, and then you realize that you've just been interpreting everything they said through your lens. And when you, when you build a different model for them, which also is a little bit of a different model for yourself, you, you can interact with these people in a totally different way and realize all the things that you have in common. And, you know, that happens with some other scientists when, but not, you know, not about their science necessarily, but just about the way they work. And you might have thought that, you know, there's somebody that you really couldn't work with. But when you sat down and you're forced to, then you get a much more detailed model, right? There's somebody that you, that you had this sort of very vague understanding of from far away, and you thought, oh, no, I don't like that person. They, they're too gruff.

They're, you know, they, they, they rub me the wrong way. But when you get to know them, you learn that, no, you know, they're just. Their way of tentatively exploring the world is by poking at it a little bit harder than I do. And so when they po. You know, part of that is poking at other people. And when you see that they're not doing it out of malice, but out of, out of curiosity, it it your understanding of their personality.

In the book you talk a lot about observations of children, especially your daughters, who I've had the pleasure to meet here in San Diego. But the kind of overarching thing is your you know, bemusement with their personalities, how they're coming to encounter the world and make models of the world and sort of you observing them observing the world. And in the book you write that all observations are theory laden. Which kind of struck a note with me that reminded me of another character in the book, which is Sir Arthur Eddington, who said never trust an experiment until there's a theory to back it up. I thought he was joking, but it sounds like you're more inclined to take him at his, at face value. What do you make of that statement?

Yeah, and I don't think he was joking or actually no one's ever, no one's sure he actually said those words. But there is a quote that I have in the book which I'm not going to reproduce here, which is a somewhat more nuanced version of that. And, and it's, yeah, this is along the lines of, of what you said, quoting me that that observation is theory laden. You can't just, you don't just sit there and see a little bit of gray over there and a little bit of yellow over there and a red patch and then kind of interpret that. You go and thinking, oh, the world is made of stuff is really made of those objects that are at different distances and made of different things. And in order to really disentangle that, you need to go into your brain and your mind need to go into the little screen of your retina which really, you know, is like a ccd. It's got lots of little, it's got lots of little, little photon receptors and somehow convert that very raw Image into a 3D time dependent picture of the world, which is what you have when you look at the world. And that's true for your visual field and it's true for all the things that you're not looking at right now.