Parallel Worlds Probably Exist. Here’s Why

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Shared March 6, 2020

The most elegant interpretation of quantum mechanics is the universe is constantly splitting
A portion of this video was sponsored by Norton. Get up to 60% off the first year (annually billed) here: or use promo code VERITASIUM

Special thanks to:
Prof. Sean Carroll
His book, a major source for this video is 'Something Deeply Hidden: Quantum Worlds and The Emergence of Spacetime'

Code for solving the Schrödinger equation by Jonny Hyman available here:

I learned quantum mechanics the traditional 'Copenhagen Interpretation' way. We can use the Schrödinger equation to solve for and evolve wave functions. Then we invoke wave-particle duality, in essence things we detect as particles can behave as waves when they aren't interacting with anything. But when there is a measurement, the wave function collapses leaving us with a definite particle detection. If we repeat the experiment many times, we find the statistics of these results mirror the amplitude of the wave function squared. Hence the Born rule came into being, saying the wave function should be interpreted statistically, that our universe at the most fundamental scale is probabilistic rather than deterministic. This did not sit well with scientists like Einstein and Schrödinger who believed there must be more going on, perhaps 'hidden variables'.

In the 1950's Hugh Everett proposed the Many Worlds interpretation of quantum mechanics. It is so logical in hindsight but with a bias towards the classical world, experiments and measurements to guide their thinking, it's understandable why the founders of quantum theory didn't come up with it. Rather than proposing different dynamics for measurement, Everett suggests that measurement is something that happens naturally in the course of quantum particles interacting with each other. The conclusion is inescapable. There is nothing special about measurement, it is just the observer becoming entangled with a wave function in a superposition. Since one observer can experience only their own branch, it appears as if the other possibilities have disappeared but in reality there is no reason why they could not still exist and just fail to interact with the other branches. This is caused by environmental decoherence.

Schrodinger's cat animation by Iván Tello
Wave functions, double slit and entanglement animation by Jonny Hyman
Filming of opening sequence by Casey Rentz

Special thanks to Mithuna Y, Raquel Nuno and Dianna Cowern for feedback on the script

Music from "Experimental 1" "Serene Story 2" "Seaweed" "Colorful Animation 4"

Fayaz P. A.

There's a version of me out there that understood the whole video.

1 year ago | [YT] | 58,472

GreenCup films

In another world Gordon Ramsay will finally find and get the lamb sauce.

1 week ago | [YT] | 959

Sir Reil

One of the only media representations I've seen on this that seemed to understand that Schrodinger was NOT trying to prove the cat was both dead and alive, but rather trying to demonstrate a problem with quantum theory.

2 weeks ago (edited) | [YT] | 625

Lol Lol

Somewhere in a parallel universe, there's a mentally, financially and a socially stable version of myself

1 week ago | [YT] | 222


You know this is a genuine university professor because his blackboard looks like it's never seen a single drop of water.

1 week ago | [YT] | 199

Guitar Lessons BobbyCrispy

A parallel world; that's where my guitar picks go whenever I drop them on the floor and can't find them.

7 months ago | [YT] | 6,434

VYTwo Yuuma

I see a lot of people who seem to be self-conscious here in these comments. I just want you remember, if you feel bad about yourself because of the supposedly better versions that could exist in parallel worlds, there's also the same number of possibilities that you also have many much worse versions of yourself in other worlds. Just be glad that you're you and hopefully not one of those terrible versions of yourself (lol). And if you are having a rough time, I wish the best for you, and I very much mean that! Let's all try our best!! (Including me, eheh...)

1 week ago (edited) | [YT] | 185


physics: "quantum particles work like probability!"
humans: "omg I have a twin somewhere!"
physics: ...

1 week ago | [YT] | 195


there’s nothing quite like a 3am existential crisis thanks youtube recommendations

1 week ago | [YT] | 226

- t h o n k i n g -

"both are not you anymore"
i am no longer me
delves into existential crisis

1 week ago | [YT] | 74


“I think it’s embarrassing we have no idea”

Me who knows nothing about quantum mechanics: wow, losers.

2 months ago | [YT] | 1,883


New title name:
“Scientist try to explain chance”

1 week ago | [YT] | 122

Anirudh Panicker

So you're telling me there is a reality where my dad came back with the milk?

2 weeks ago | [YT] | 291


After watching Rick and Morty this makes total sense.

5 days ago | [YT] | 8

Global and historical thoughts

In a parallel universe, Epstein still didn’t himself.

16 hours ago | [YT] | 1

Rohit Tiwari

Schrodinger: we don't know whether cat is alive or dead inside the box, until we open it.
Cat inside the closed box: Meeoowww.....
Schrodinger: Shut up

3 weeks ago | [YT] | 3,324


It's a good video, but it vastly overstates the confidence anyone should have that the many worlds interpretation (MWI) of quantum mechanics is the correct one. Certainly it is more elegant than many interpretations, but no more so than information-theoretic ones, but it is untested (as all interpretations are) and has no prospect of being tested in the foreseeable future. Without a path to experimental assessment, all interpretations of QM should really be thought of more as stories we are telling ourselves, not as science.

1 week ago (edited) | [YT] | 26

Bruno Presotto

Things would be much less complicated if Schrodinger used a transparent acrylic box...

1 week ago | [YT] | 103

Carlo Gaytan

Schrodinger's Cat theory is all cool. It get stupid when people dont want to know important things on purpose because technically they wont have a disease or health problems as long as they dont go for a checkup.

1 week ago | [YT] | 28


"It's a very low amplitude world", is a wonderful way to say "it's very unlikely"

2 weeks ago | [YT] | 31