THE SCIENTIST & THE ENGINEER

Within moments of beginning our interview, the two men seem to forget my presence.

THE SCIENTIST, the younger of the two, is a man given to making grandiose statements about the nature of reality. "It's a shame," he says, "that the replicator is only being used to replicate non-living physical matter. The real potential of this technology is much greater."

THE ENGINEER scoffs, scratching at a bald patch on his head, and says, "You keep saying that, but there's no reason to think we'll ever get it working on living matter. And don't get started talking about teleporters again."

THE SCIENTIST: Fundamentally, a replicator is a teleporter. There's no difference.

THE ENGINEER: Horseshit. Replicators print copies. Those copies aren't the original thing, they're just exactly like the original thing. The original matter is lost, not transported. So, imagine if we fixed The Syrup Problem. If you scanned yourself into a big rep, and then sent the backup file to another rep far away and printed out a new one, that's not you. That's just a copy who thinks he's you.

You said, "The Syrup Problem?"

THE SCIENTIST: It's a little name we've given to a particular issue with the current generation of replicators. For whatever reason, reps today have trouble copying viscous liquids. Maple syrup was always the example we used.

We spent months just trying to print out good syrup. Never did quite get it. We think it's somehow connected to the fact that you can't yet use reps to make copies of living creatures.

THE ENGINEER: He says, "can't yet," and I say, "can't ever." Lord knows I've lost hair trying to solve it. You wouldn't believe how many mice I've disintegrated. The copies always come out dead as a doornail. Maybe because of The Syrup Problem, their blood is too runny? Or maybe the two issues aren't related at all. Nobody knows, and at this point I doubt we ever will.

THE SCIENTIST: Always the skeptic. Look, one day we're going to solve The Syrup Problem. And when we do, we're going to have to deal with human replications. And the debate we're having right now is still going to be going on.

THE ENGINEER: Maybe The Syrup Problem is the answer to the debate. Perhaps the viscosity of our inner fluids is the irreplicable, immutable quality of life. (Laughs.)

THE SCIENTIST: Now you're being absurd. Look, this problem isn't something unique to teleportation. Think about this. Every night, you go to bed thinking you're THE ENGINEER. And when you wake up in the morning, you still think you're THE ENGINEER. But during the night, millions of your cells have died off and been replaced. And new ones have grown.

When you wake up, you're using altered hardware. But because it's so similar, and because you have the same memories, you have the illusion that the same ENGINEER who went to sleep is the same ENGINEER who woke up. Your identity is based on a false sense of continuity. Call it the illusion of continuity.

THE ENGINEER: I take issue with your example. Sure, some of my cells are replaced every night when I'm sleeping. But most remained unchanged. And I'm pretty sure it takes like 30 years for brain cells to replace themselves.

When I wake up, the reason I think I'm the same person is because I have a brain that's 99.99% the same. And anyway, it's not like some clone came and took my place in the bed in the middle of the night.

So, frankly, you're the one who's being absurd. If I got backed up to a rep and printed out somewhere else, I'd be dead and the new guy would know, deep down, that he was just a branch cut off the original. The memory of being killed in the rep would destroy my copy's "illusion of continuity," as you put it.

THE SCIENTIST: Hm… I don't know, actually. What if you were sedated before being put into the rep? Then any copies of you would come out still under sedation, and when you woke up, your last memory would still be of drifting peacefully into sleep.

I think the memories thing may be the key to all of this. If memories are a function of the configuration of brain cells, then a replicated copy of a person would have the exact same memories, because they'd have the same brain structure. And the entire illusion of self is built atop a foundation of continuity and memories, real or imagined.

THE ENGINEER: Okay, let's say you're right, and it's really all just memories, brain structure, and the illusion of continuity. What if one day we're able to invent a replicator that can scan living creatures without destroying the original? And then I back myself up to that rep and print out a copy. Are you saying that both the copy of me and the original version of me would both be... me?

THE SCIENTIST: Sure, why not?

THE ENGINEER: That is dumb as fuck.