Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • FUTURES

You don’t get to choose entanglement

Two human hands reach for each other as they begin to fragment in space

Illustration by Jacey

“Pick the best year of your life. That’s where we can retire you to.”

You would think it would be hard to sell something that disappears you forever. But if you pick the right applicant, if you give it the right spin, well … I mean, take this guy — Geoffrey Chalmers, 60, no family, no kids, married for an eon, now a widower to cancer. It’s all there in his application. All alone, probably dreaming of better days — youth, love, adventure. Could be an easy sale.

“Have you heard of the many worlds theory?”

Of course he has — he is sitting in my office, after all. But it doesn’t hurt to lay it all out as simply as possible. Not everyone is a quantum physicist — or a multiverse-retirement sales rep.

“Imagine that among all those infinite worlds, there are some that are very different, but many that are almost the same as here. Practically identical, except something tiny, like, oh, the taste of an apple being different.”

Chalmers just shakes his head. OK, so one fruit analogy doesn’t provide the same background as the company training does, but he seems a tad slow on the uptake. I’m not surprised, though — some people his age can’t even set up a simple holoscreen.

“No matter. What’s important is that the theory is now a practicality. I don’t understand much about wavefunctions and entanglement myself, but this way, you get a nice retirement, and our system gets a breather from a … maturing population. That’s why we are so heavily subsidized, and why your pension provider lists us as an option. Lots of people are keen for this to get traction.”

“Wavefunctions? Entanglement?”

“It’s quantum mechanics. You don’t need to know how a hydrogen engine works to drive a car, do you? Just know the technology works, and it will get you from A to B. So to speak.”

Sometimes that gets a laugh, sometimes not. But Chalmers hasn’t been very responsive so far, so I figure it’s worth a try.

He doesn’t laugh, or even smile.

“Any year?” he asks. “How?”

I try not to grin. Easy sale.

“With infinite worlds, it’s easy enough to find a subset almost exactly the same as this one, but with one very particular difference.”

“Which is?”

“You don’t exist. Well, more precisely, we pick worlds in which you die right at the time you want to be inserted. Detecting that particular subset is easy. Once we find one, we doppelgänger you in, so to speak, and swap you out after a year. And so on.”

“And after that year I’m, what, dead in that world? Missing?”

I shrug, trying for casual. This bit can make some a little hesitant. “You were going to be gone anyway. But we can put your dead self into stasis and swap it back in after the year. What with the subsidies and various packages, we have many options.”

“For how long?”

I spread my hands. “By keeping it to a year timespan, we can keep the searching for worlds manageable, and the energy expenditure within cost, so we can offer everyone up to their centenary. That gives you 40 years. And we will leave you in your last world, so you get however more years there. Also, I should point out a quirk of the multiverse — you look and feel the appropriate age for when we insert you. So if we put you in at 25, say, you look that age. You won’t be trying to play late-night basketball in a 70-year-old’s body.”

“I’m not a sports guy.”

“Dance the night away with a lovely lady, then.” I don’t quite mention the wife. “Whatever you like. But you get my drift. It’s about entanglement again.”

“Entanglement. You said that before.”

I stifle a sigh. This is starting to get a little repetitive.

“All I know is you don’t get to choose entanglement, it just happens. On a quantum level, it’s how you are connected to everything around you. If you want a year 20 years ago, we put you in a universe that has an apparent age 20 years younger than this one. So when you get entangled there … well, most people are quite excited about that aspect.”

“Entanglement is connection,” he repeats slowly, and I feel like hitting my head on the desk. Usually by now they are either very excited or ready to opt out.

“Any year, you say?” he asks again. My frustration disappears and again I try not to grin. I give him some package options, and send him away to think.

*****

“I’ve decided to go.”

I smile. “You’ve picked your year?”

Chalmers just nods. “Last year.”

I feel my smile dry up and blow away. I mean, I’ve read his application.

“Um,” I say. “You spent most of last year nursing your wife through her late-stage cancer. Home hospice mostly. Surely not the best year …”

He does smile then — a tired, sad smile that stops me mid-sentence.

“In the worlds where I die at the start of last year, she goes through her final year alone.”

It takes a moment for that to sink in.

“You can’t seriously be going to spend 40 years doing this!”

I wonder why I am bothering even as I speak. A sale is a sale, after all. It’s just, well, he could have any year.

Chalmers just keeps on with his sad smile. “I think you were right. You don’t understand entanglement. But I do.”

The story behind the story

Matt Tighe reveals the inspiration behind You don’t get to choose entanglement.

This story grew from an unlikely seed, and is really about two things.

I’ve said it before — I am not a physicist. But I do find the language they use kind of beautiful. I keep skimming articles, dodging the maths and hoping for some light bulb to blink on above my head. I was doing this with some articles online about multiple-world theory, and as usual I bounced from definition to definition, winding up way down a rabbit hole of concepts and theories I was amazingly ignorant about. What I really needed was someone to explain it all to me — to sell me on the concept — I thought. Of course, we seem to have a history of packaging up and selling discoveries, whether we should or not. I wondered what that person would be like — someone who knew enough to sell the idea of multiple worlds, but who perhaps didn’t appreciate the true import of the discovery. The idea of a salesperson hawking such an amazing discovery was so crass, so upsetting, and so very possible that I couldn’t shake it.

The second thing this story is about is how I feel about my wife. I am well and truly entangled, and I think that kind of love easily makes up for any crassness out there.

doi: https://doi.org/10.1038/d41586-021-02159-5

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing

Search

Quick links