Physics itself—not technology, not human ingenuity—forbids perfect cloning, which might throw a kink in any plans to upload your brain. Find out why in this episode of What the Physics?!
Can You Upload Your Brain?
Published May 17, 2018
Greg Kestin: This is Pepper, my childhood dog, and I scanned her so I'd have that picture of her forever. Most of the time, uploaded copies are pretty close to the original. For example, you could upload a perfectly functional copy of your hard drive to the cloud. Scientists have uploaded—and 3D-printed--a silicone heart that beats just like a human heart. But could you upload your brain? And if you could, could you do it without destroying it?
People have been building machines which mimic the human brain for nearly 80 years. In that time, so-called neural networks have learned to perform human tasks, like recognizing handwriting, speech patterns, and your friends’ faces. But would it be possible, even in principle to create a replica of your brain?
Say you connected 100 billion neurons in the arrangement of neurons in your brain. Would that act like you--with a personality and a sense of identity? Maybe you would actually have to copy all of the atoms and molecules. After all, it's the ions in your brain that send the electricity through your neurons and actually control you.
It's possible that's not even enough. To make a perfect copy of your brain, you'd have to copy all the way down to the level of the quantum states of the fundamental particles. There's reason to think these quantum states are critical. Birds likely use quantum mechanics in their navigation. Plants use quantum mechanics in photosynthesis. And it's not unthinkable that we have important quantum processes going on in our brain.
Now, we haven't figured that out quite yet, but would it even be possible to copy those quantum states?
A few years ago, physicists teleported a photon between two Canary Islands. First, they observed a photon in a particular state on one island. Then they took that information and put a photon on the second island in that same state. It wasn't literally the same photon that disappeared from one island and appeared on the other, but it was a perfect copy.
Here's the problem: The simple act of observing the first photon's state altered the photon beyond recognition. The standard way to make a copy is to scan the original first. But quantum states are kind of like vampires. If you shine a light on them--that is, observe them--then you destroy the state. You alter them beyond recovery.
You can build a computer without worrying about its quantum states. Not every quantum process has a function. Sometimes it's just part of the noise. But if your brain is different and you do need to copy it down to the quantum level to replicate and upload it, making that copy would destroy your brain as you know it.
The good news is, whether you copy your brain or not, there can only ever be one you.
PRODUCTION CREDITS Host, Producer Greg Kestin Writing and Research Samia Bouzid
Greg Kestin Editorial Input from Julia Cort
Ari Daniel Filming, Editing, and Animation Greg Kestin
Samia Bouzid Scientific Consultants Mark Hillery
Scott Aaronson Special thanks Entire NOVA team From the producers of PBS NOVA © WGBH Educational Foundation Funding provided by FQXi Silicone heart footage courtesy of ETH Zürich Music provided by APM Sound effects provided by Freesound.org