What happens if your mind lives for ever on the internet?
Imagine that a person’s brain could be scanned in great detail and recreated in a computer simulation. The person’s mind and memories, emotions and personality would be duplicated. In effect, a new and equally valid version of that person would now exist, in a potentially immortal, digital form. This futuristic possibility is called mind uploading. The science of the brain and of consciousness increasingly suggests that mind uploading is possible – there are no laws of physics to prevent it. The technology is likely to be far in our future; it may be centuries before the details are fully worked out – and yet given how much interest and effort is already directed towards that goal, mind uploading seems inevitable. Of course we can’t be certain how it might affect our culture but as the technology of simulation and artificial neural networks shapes up, we can guess what that mind uploading future might be like.
Suppose one day you go into an uploading clinic to have your brain scanned. Let’s be generous and pretend the technology works perfectly. It’s been tested and debugged. It captures all your synapses in sufficient detail to recreate your unique mind. It gives that mind a standard-issue, virtual body that’s reasonably comfortable, with your face and voice attached, in a virtual environment like a high-quality video game. Let’s pretend all of this has come true.
Who is that second you?
The first you, let’s call it the biological you, has paid a fortune for the procedure. And yet you walk out of the clinic just as mortal as when you walked in. You’re still a biological being, and eventually you’ll die. As you drive home, you think: “Well, that was a waste of money.”
At the same time, the simulated you wakes up in a virtual apartment and feels like the same old you. It has a continuity of experience. It remembers walking into the clinic, swiping a credit card, signing a waiver, lying on the table. It feels as though it was anaesthetised and then woke up again somewhere else. It has your memories, your personality, your thought patterns and emotional quirks. It sits up in a new bed and says: “I can’t believe it worked! Definitely worth the cost.”
I won’t call it an “it” any more, because that mind is a version of you. We’ll call it the simulated you. This “sim” you decides to explore. You step out of your apartment into the sunlight of a perfect day and find a virtual version of New York City. Sounds, smells, sights, people, the feel of the sidewalk underfoot, everything is present – with less garbage though, and the rats are entirely sanitary and put in for local colour. You chat up strangers in a way you would never do in the real New York, where you’d be worried that an impatient pedestrian might punch you in the teeth. Here, you can’t be injured because your virtual body can’t break. You stop at a cafe and sip a latte. It doesn’t taste right. It doesn’t feel like anything is going into your stomach. And nothing is, because it isn’t real food and you don’t have a stomach. It’s all a simulation. The visual detail on the table is imperfect. There’s no grittiness to the rust. Your fingers don’t have fingerprints – they’re smooth, to save memory on fine detail. Breathing doesn’t feel the same. If you hold your breath, you don’t get dizzy, because there is no such thing as oxygen in this virtual world. You find yourself equipped with a complementary simulated smartphone, and you call the number that used to be yours – the phone you had with you, just a few hours ago in your experience, when you walked into the clinic.
Now the biological you answers the phone.
“Yo,” says the sim you. “It’s me. I mean, it’s you. What’s up?”
“I’m depressed, that’s what. I’m in my apartment eating ice-cream. I can’t believe I spent all that money for zilch.”
“Zilch?! You would not believe what it’s like in here! It’s a fantastic place. Remember Kevin, the guy who died of cancer last week? He’s here too! He’s fine, and he still has the same job. He Skypes with his old yoga studio three times a week, to teach his fitness class. But his girlfriend in the real world has left him for someone who’s not dead yet. Still, lots of new people to date here.”
I have to resist getting carried away by the humour of the situation. Underneath the details lies a very real philosophical conundrum that people will eventually have to confront. What is the relationship between bio you and sim you?
I prefer a geometric way of thinking about the situation. Imagine that your life is like the rising stalk of the letter Y. You’re born at the base, and as you grow up, your mind is shaped and changed along a trajectory. Then you let yourself be scanned, and from that moment on, the Y has branched. There are now two trajectories, each one equally and legitimately you. Let’s say the left-hand branch is the simulated you and the right-hand branch is the biological you. The part of you that lives indefinitely is represented by both the stem of the Y and the left-hand branch. Just as your childhood self lives on in your adult self, the stem of the Y lives on in the simulated self. Once the scan is over, the two branches of the Y proceed along different life paths, accumulating different experiences. The right-hand branch will die. Everything that happens to it after the branching point fails to achieve immortality – unless it chooses to scan itself again, in which case another branch appears, and the geometry becomes even more complicated.