Hello everyone, welcome to the Mindscape Podcast. I'm your host Sean Carroll. You may know

from listening to Mindscape in general or my AMAs in particular or reading any of my

books, there's something out there called the Multiverse. Well, what I should say is there's

an idea out there called the Multiverse. We don't know for absolute certainty whether

or not there actually is a Multiverse out there. In fact, there are different kinds of

Multiverse, which I would assign different credences to taking seriously. There's a quantum

mechanical kind of Multiverse, which I take very seriously. There is a cosmological kind

of Multiverse where literally just very, very far away, there's different pockets of

space time where things behave differently that I'm kind of indifferent about. Maybe it's

there, maybe it's not. There's good reasons to take it seriously, but we honestly just

don't know. There's also more philosophical kinds of Multiverse, the philosopher David

Lewis famously advocated modal realism, the belief that every possible version of the

universe is actually real in some sense. And the question of figuring out which universe

we live in is just locating ourselves in the space of all possible worlds. You may also

have noticed that the idea of the Multiverse has moved beyond science and philosophy to

narrative, to movies, TV shows, books, things like that. This is not a completely new move.

Fiction writers have used the notion of a Multiverse as a device for decades now, but

it's gaining popularity a little bit. Back when we had Scott Derrickson as the guest

here on Mindscape, he had just come off directing Dr. Strange, the Marvel movie, the new sequel,

it will be Dr. Strange and the Multiverse of Madness, which follows up on the most recent

Spider-Man movie, which also investigated the Multiverse idea. So it's out there, okay,

we're using it. There's a new movie, which I very much encourage you to see, called

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