Universes Aren't Real

But stars are! I remain firm on this point!

It’s been bugging me that, even though I named this substack “Outlandish Claims,” my post titles haven’t been all that outlandish. Then I realized I could title one “Universes Aren’t Real” in good conscience! It’s barely a troll at all! This is something I actually believe.

“Real” and “unreal” aren’t properties you can assign to universes (even ours). It’s roughly analogous to how you can ask, for every place on Earth, “is it night or day there?” But you can’t ask “is it night or day on Earth?” It’s nonsense.

At least, you can’t describe universes that way if you’re using my terminology. Anyone’s word definitions are at best a useful framework, never capital-T Truth.

Glossary

Universe: To define a universe, pick any one object that’s part of it. Then, add in everything that every interacted with it, or helped create it. Also, add in everything it could potentially interact with, or create, in the future. Then repeat this process for each of those things you just added, and so on and so on until you don’t have anything more to add. All of that is one universe. (More tersely but more jargony: a universe is a closure over the “can-interact” relationship.)

This definition mostly adds up to how we use the word, but it does mean you can’t call alternate quantum realities (Everett branches) “universes”, because they’re not quite separate. Also, it rules out by definition a machine that lets you transport yourself to “another universe”—the existence of the machine merges the two. Just call it another dimension, or something, for these purposes.

Real: Something is real if I could, in principle, interact with it.

An important thing about this definition is the “I”. Things aren’t flatly real or unreal, just like things can’t be higher or lower. They’re real or unreal only in relation to other things. I’m going to overexplain this point for fun. I’m reading Brandon Sanderson’s Mistborn at the moment, a novel about a team of con artists. In the story, they’ve just created a fake person as part of a con: Lady Valette Renoux. Wait, what does that mean? They’re all fake people. But Lady Valette Renoux is the only one who isn’t real in the context of the story. (As far as I know. No spoilers!) Valette and Kelsier are equally unreal to me. I will never meet either outside the page. On the other hand, anyone in the story could meet Kelsier, but couldn’t possibly meet Valette. So Kelsier is real to them.

(I’m delighted to find that Nestflix still exists at the time of this writing—a site for browsing through media that only exists in the context of other media, like the gangster movie Kevin watches in Home Alone. I only know of one case of a doubly-nested TV show: in 30 Rock, the show Dealbreakers never makes it to air, but is shown in the background on TV screens in other shows from the same network. I can’t really explain why I love this stuff but if you know, you know.)

Okay, now on to the argument.

Why Universes Aren’t Real

It follows trivially from the definitions of “universe” and “real.” For any given universe, nothing other than the universe itself can interact with it. So there’s no external perspective from which the universe can be said to be real. Or fake, for that matter.

This concludes the argument.

Okay, ha, ha. What’s the point?

The big win for this framework is it eliminates what Heidegger called the fundamental question of metaphysics: Why is there something instead of nothing? (Heidegger was a dick, so let’s try to make him as irrelevant as possible). The “something” in question is the universe, so it neither “is” nor “isn’t.” We can and should ask why echidnas exist, because they do, and they’re weird, but we don’t need to ask why everything exists, because it doesn’t.

Dissolving this question is much less satisfying a solution than answering it, which would presumably involve learning something about the universe, like the nature of God, or whatever. But this solution has the advantage of being correct.

“That just raises further questions!”

The analogous question, within this framework, is “why do we find ourselves in this particular universe, rather than some other one?”

That one is highly nontrivial, and answering it fully would indeed involve learning something fundamental about the universe. I can’t answer it fully, but I can sketch the beginning of an answer.

First of all, here’s another nonsense question. Suppose you’re doing a Q+A in front of an audience, and it’s all being broadcast live (am I dating myself? should I just say livestreamed?) and recorded. Somebody stands up and asks you “Are we in the live broadcast or the recording right now?”

Um? Both, I guess. If you said “this is live,” people watching the recording will be like “nope”. And vice versa.

Okay. Let’s try another one: is this reality, or are we living in a simulation?

That one feels kind of sensical, but it’s really the same breed of nonsense. Consider the universe where nigh-unbounded computing power, enough to simulate our entire observed reality, is super cheap, and someone is doing just that and watching us. If we say this is reality, they’ll be like “nope.” But if we say this is a simulation, then…what’s being simulated? A non-simulated universe, that’s what. There must be a context where you’re wrong. And remember, universes aren’t real, nor are they hypothetical. They’re all just…universes. So any answer we give, to be completely correct, has to take every universe in which our experiences could take place into account.

So we don’t, exactly, find ourselves in one particular universe. We’re in a reality governed by physical laws, and we’re in every reality where the behavior of those laws is being simulated. We’re running on all kinds of different hardware, for all kinds of different reasons. We’re nested any number of layers deep in simulations within simulations. We’re running on naturally occurring computers formed by random chance. The only point of commonality is that each universe we’re in has to account for our experiences in some way. As soon as the experience we’re having differs between universes (say, someone decides to mess with the simulation), people stop being in both at the same time—there are now different versions of you, one experiencing life continuing as it was before, and the other seeing the sky suddenly turn into static.

One testable prediction I’m making here is that we’ll never experience the second kind of thing. There are always going to be “more” universes where the simulation keeps running as before, than ones where a higher reality interferes. Interference requires specificity—means, motive, and opportunity to interfere, or an asteroid hitting the planet. Noninterference can happen in all sorts of different contexts. So in that sense, more versions of us will be living in no-detectable-interference scenarios.

So here’s the nature of existence. We’re living in the intersection of infinite universes, many of them radically different from each other. That intersection, itself, is something conducive to being simulated, probably because it’s a set of deterministic physical laws that allow for complex behavior. That’s why we find ourselves in this particular universe—it’s a story many different places are interested in telling. Some of them will decide to stop telling it, in the future, but others will keep it going. So in practical terms, we’re not living in a simulation, we’re living in physics.

Bonus: The Tommy Westphall Universe

The long-running TV medical drama St. Elsewhere had an interesting ending. It seemed to imply that the entire show had been imaginary—a kid named Tommy Westphall was imagining that his father was a doctor. I’m pretty sure my mom is still salty about this. 30 Rock referenced it in its own finale, but nobody was that invested in how many levels of reality 30 Rock had. St. Elsewhere, though? It stings, weirdly, to have a drama tell you it’s double-fake instead of just regular fake.

A few people did something fun, though: they started thinking it through. Tommy clearly has a godlike intellect and knowledge beyond his years, to be able to imagine all of these adult goings-on in such detail. Okay, sure. It’s TV, you’re allowed to have fantastic elements. But also—St. Elsewhere had crossovers with other TV shows. Two of the doctors appeared in Homicide: Life on the Street. If Homicide is capable of interacting with St. Elsewhere, it must be on the same level of reality. So Tommy must be imagining Homicide too.

Then (hooray!) you recurse. The character detective John Munch originated in Homicide. You may remember him from every other police procedural show you’ve ever watched, even if you stretch the definition to include things like Arrested Development or The X-Files. He had a lot of cameos. So Tommy’s imagining all of those, too. It’s just logic.

Then, you recurse…