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If I Die, Do All My Quantum Selves Die, Too?

We hope you are either very clever or very high for this one

The reality you think you’re living in isn’t what you think it is.

That’s according to some physicists, who believe in a theory called the Many Worlds Interpretation — we’ll get into the nitty gritty in a moment, but the tl:dr version is that there are an infinite number of different versions of you out there in an equally infinite number of parallel universes. And despite sounding like something your 15-year-old cousin might come up with between bong hits, it’s legitimately based on quantum mechanics — a 100-year-old field that’s among the best-tested theories in all of science.

Anyway, a question that’s been nagging us recently is, what happens to all these quantum selves when something happens to you? We’ve boiled down the answers with the help of professor Ken Intriligator, an expert in quantum mechanics at the University of California, San Diego, for this not at all high-as-balls-sounding FAQ.

So, like, what’s the deal with all these versions of me in all these universes?

The gist of the Many Worlds Interpretation, as Intriligator explains it, is that you aren’t living a unique, linear life like we’ve all assumed since the beginning of time. In fact, what we think as the beginning of time might not even be the beginning. A layperson’s example would go like this: Every decision you make (say, whether to get out of bed or sleep in) is a branch point, and depending on what you did, there’s an alternate universe that spins off into existence where you did the other thing. So if you slept in, there’s another universe that branches out in which you woke up instead, and the rest of your life proceeds from there.

Uh, what?

Yeah. If you start to think about it, you’ll realize the infinite possibilities. All the millions of decisions you make, the millions of decisions your parents made, all the way back to the Big Bang. But guess what? According to Intriligator, in the Many Worlds Interpretation with multiple universes, the Big Bang isn’t the beginning of time as we know it. “Just to give an analogy, if you’re boiling water, and there are lots of bubbles in the water, it’s kind of like when the universe was created,” Intriligator says. “Our universe is like one of those bubbles. So we’re in one of those bubbles. But there could be lots of other little bubbles, and it might be that we never know about the other ones, and so there could be lots of different universes.”

How seriously do physicists take this theory?

That’s tough to say, and Intriligator is upfront about the fact that he doesn’t necessarily buy into it (he was simply kind enough to break it down for us). The thing about quantum mechanics is that its rules work on a subatomic scale, but not necessarily on a human scale. “Quantum mechanics is very strange because once you learn it, it seems that everything we know about how the world works is basically wrong in some totally different way, and we don’t notice it because we’re too big to notice it,” Intriligator says. “So maybe our senses kind of average out these things, but then when we try and fit these observations with the way we normally think about these things, it becomes really confusing.”

One way to square that circle — and to take quantum mechanics to its logical conclusion — is the Many Worlds Interpretation, which was born back in the 1950s. But not everyone is onboard: “If you take the starting point of Many Worlds, most physicists would say it probably sounds right,” Intriligator says. “But if you follow it to its logical conclusion you have this really weird thing where everything is constantly branching into these different universes and different realities, and that’s really freaky! For many people, that’s too far.”

There’s also an academic angle to this — while many young physicists start out working on the science, as they get older, many start to wonder what it all means, and start looking for interpretations of quantum mechanics in life. “In some ways, thinking seriously about it is considered a dangerous thing, because it’s like, once you go off in that direction, it becomes more like philosophy than science,” Intriligator says.

In short, it has its devotees in the science world, but it’s definitely not for everyone.

So how do these branch points work? Is it, like, every time I decide between loading up another bong or going out to buy Pop Tarts, in some universe somewhere, both options play out?

It’s not actually this simple. It all supposedly works on a subatomic scale, so it’s not about deciding whether to do this or do that, it has to do with the position of each electron in the universe (or rather, the multiverse). Yeah, it’s that small. And it means there are a lot of different universes where each electron plays out its possibilities.

Soooo… uhhh… how does that relate to the decisions I’m supposedly making?

Okay, here’s the baffling part about quantum mechanics: There’s probability and uncertainty involved, which even Einstein didn’t like (he famously said about quantum mechanics that, “God does not play dice with the universe”). But then, maybe that sort of makes sense in the grand scheme of things? Think about it: If everything in life were predetermined, and you could conceivably figure out the initial conditions of the universe when it started, if you came up with the right equation you could predict literally everything, since we’re all just basically bundles of atoms moving according to some sort of equation. There would, in other words, be no free will.

But with quantum mechanics and its uncertainty, you see that there’s a chance you did or didn’t get out of bed, to use the initial example. So there might be randomness, but whichever one you chose is the reality you’re in. “So in fact there are some people who try and connect free will and consciousness to quantum mechanics,” Intriligator says. “Because if you didn’t have quantum mechanics you might think that everything is kind of predetermined. It’s all really weird stuff.”

Guh. My head feels weird. Ooh, and my hands look weird, did you ever notice that? Wait, where was I? Oh yeah. Will science ever figure this stuff out for real?

It’s possible — science is always advancing, after all. Here’s what Intriligator says: “Even people who’ve spent their whole life working on quantum mechanics, like me — at a fundamental level I really feel like I understand the math and various things like this, but what does it mean? That’s a really big mystery,” he says. “There’s a chance we just haven’t been thinking about it right for a hundred years — that there’s something that we’re missing — and someday someone will fill in some missing gap and everyone will be kicking themselves that they didn’t see that.”

I’m pretty sure I came here with a question…

Oh yes — you were wondering, if I die, do my other selves die too? The answer: Nope. According to the Many Worlds Interpretation you’ll keep on keeping on in all those other universes — universes where you didn’t get cancer, didn’t get behind the wheel or didn’t take that too-big bite of sandwich. There will still be infinite versions of you out there, somewhere, depending on all the weird shit going on in those other universes.

That sounds… comforting. Is that comforting?

Maybe. Maybe not. But it might just be true.