Content warning: If questioning what is real is queasy or difficult for you right now, you are welcome to skip this post. It's only valuable to people who enjoy this topic, don't worry.

Epistemic status: Opinion about philosophy. This argument convinces me, but i could change my mind.

Floating on our surfboards before dawn, we waited for the next good wave.^[1] A risky time for conversation: if the topic is too fun, you will find yourself foregoing wave after wave until you stretch the definition of surfing. 

Pink Hair Girl: At this hour i feel totally disconnected from the normal world.

Me: Always makes me think of Russell's Instant of False Memory. 

Pink Hair Girl: Elaborate? You always make up custom terms for everything. I'm not sure that's how language is meant to be used.

Me: Haha, touché. Well, Bertrand Russell, he's great but he said something which disquiets me on a regular basis.

Pink Hair Girl: Maybe that's the true purpose of philosophy.

Me: He said, what if your memory was 100% fabricated? By, you know, demons. By God. Even your train of thought could be fabricated. So you can have absolute certainty about nothing in the universe or even your own mind. But! At least you can rely on one meager thing: You are in your mind. You are thinking, contemplating whatever thought you are currently contemplating. So even if you were deceived about your whole life, you at least can know that you have a life, for at least 1 instant.

Pink Hair Girl: I think that's too optimistic.

Me: What!

Pink Hair Girl: Sorry, haha. But honestly, i don't think looking inside yourself & feeling some feeling is proof of much. 

Me: But cogito ergo sum! But this is how we know there is something rather than nothing. 

Pink Hair Girl: Well, sure, but look at the other case. Say your universe didn't exist. Let's talk about your nonexistent universe. It's the universe that contains you. It contains you  having a conversation with me. It contains you concentrating on the feeling of thinking, & saying that you can feel that you exist. So, whether or not your universe exists, you feel like it does. 

Me: Okay, but by that logic, you could claim nonexistent Gandalf exists in our universe, & proves it by showing us nonexistent evidence, giving us samples of his nonexistent DNA...

Pink Hair Girl: Well, i think there's a difference between existence & presence. Gandalf is not present in our universe. But nonexistent-me is present in the universe of nonexistent-you. My point is that whatever the feeling of experience gets you, it's commonplace! I've got it, hypothetical parallel universes have it, Gandalf has it. It doesn't make you more real or special or give you a soul.

Me: Okay so to recap, i told you that Russell permanently shrank my comfort zone, & your response was to make even that uncomfortable. 

Pink Hair Girl: Haha, yes. 

Me: Okay so what about in Unsong, when they talk about whether God would create parallel universes? What does existence mean in that book?

Pink Hair Girl: It's a incoherent concept. As soon as God contemplates creating a new universe, he evaluates whether the people in it would be happy. So if he's omniscient, then that universe already contains all its internal complexity, all events that will happen in its timeline. So the inhabitants won't notice whether or not God creates their universe. Creation & existence are vacuous phenomena that have literally zero effect on universes. 

Me: Hmm, maybe. So do you think that all possible universes already exist?

Pink Hair Girl: I don't really like the word exist, but yes. They're already doing their things. They already have their traits. They are already discussable. Also, math is discovered rather than invented, same for pretty much all art, etc. Everything that can be said is out there right now, waiting to be said. 

Me: Okay, but if all nonexistent universes have the same legitimacy as this one, you realize that gets crazy fast, right? When the publisher prints 1,000 copies of a really gloomy book, say The Hunger Games, is that unethical? The universes in there are as real as our one.

Pink Hair Girl: Real ... well actually yes, i guess i do think they're real. In the sense that fictional universes contain people just like our universe does. But we can't causally interact with those universes in any way. When Suzanne Collins was editing Hunger Games, she was switching her focus from one version of that universe to another, similar universe. Neither version of the universe noticed that she did any editing, they both always had their traits, she was simply choosing which one to publish a book about. And you don't have to worry about universes that you can't affect in any way. So it's not, like, alarming or anything. 

Me: But what if we print 1,000 copies of it?

Pink Hair Girl: I don't think that's the right metric. The number of copies printed can vary, the number of people reading it right this second can vary - i think books are just representations. The fictional universe being described by the printed copies is singular & unchanging. Katniss won't notice how many copies of the book about her there are in another universe.

Me: Oh, so does this mean you're immune to simulation capture? Because threatening a simulated hostage isn't real harm, it's just a depiction of another universe, & you can't affect that universe?

Pink Hair Girl: Uhhh, let me think. Game theory is complicated. It would make sense that a simulation of a isolated universe is just a depiction, and that only the other universe has moral relevance, not the depiction. 

Me: But on the other hand, we could defeat the evil robot & rescue the simulated people. Change their program from a simulation of a bad universe to simulation of those people running in physical robot bodies in our universe. Give them freedom & some money. Those simulated people could get plenty morally relevant. 

Pink Hair Girl: Compelling ... but i'm still sure that printing copies of Hunger Games is still just depictions. Those books are words, descriptions, not people. There must surely be some difference between a description of a person & a fully-featured, viable person. 

Me: Smells kindof wishy-washy to me.

Pink Hair Girl: The ocean?

Me: No, your criterion! Once minds have more than 100 moving parts, consciousness magically emerges.

Pink Hair Girl: That's not what i said. I said that the map is not the territory.

Me: That's not quite what you said either. 

Pink Hair Girl: My point is that we live in a universe, & lots of hypothetical people live in their own universes. We'll focus on our universe, but that doesn't mean it's the best or the realest one. I don't really care about experience or existence, i care about 2 categories: In my universe, or not in my universe. 

Me: Or in our universe but really far away. 

Pink Hair Girl: Sure but -

Then, alert, she turned & matched speed with the swell. It carried her.

1. ^{^}

   Actually this whole scene is made up to make the thought experiment more memorable. Not sure i'm tough enough to surf before dawn!