In Robert J. Sawyer’s book Mindscan, the main character has his mind copied and uploaded into a robotic version of himself so that he (in his new robotic body) can live on without fear of sudden death from a medical condition his original biological self suffers from. But once the copy is made, they can’t just murder the original…
“All right, Mr. Sullivan, you can come out now.” It was Dr. Killian’s voice, with its Jamaican lilt.
My heart sank. No…
“Mr. Sullivan? We’ve finished the scanning. It you’ll press the red button…”
It hit me like a ton of bricks, like a tidal wave of blood. No! I should be somewhere else, but I wasn’t.
Damn it all, I wasn’t.
“If you need help getting out…” offered Killian.
I reflexively brought up my hands, patting my chest, feeling the softness of it, feeling it rise and fall. Jesus Christ!
“I’m coming, damn it. I’m coming.”
I hit the button without looking at it, and the bed slid out of the scanning tube, emerging feet-first; a breech birth. Damn! Damn! Damn!
I hadn’t exerted myself at all, but my breathing was rapid, shallow. If only—
I felt a hand cupping my elbow. “I’ve got you, Mr. Sullivan,” said Killian. “Upsa-daisy…” My feet connected with the harsh tile floor. I had known intellectually that it had been a fifty-fifty shot, but I’d only thought about what it was going to be like to wake up in a new, healthy, artificial body. I hadn’t really considered…”
– from “Mindscan”, by Robert J Sawyer
If this were possible, if you could duplicate yourself or copy your mind into another body, who would be the real you? What’s the definition of a person? An individual? That’s the sort of thing this book talks about. For a nonfiction approach to the problem of personhood, there’s Jeff McMahan’s The Ethics of Killing.
Sawyer and McMahan, as is the general intuition (if there is such a thing), seem to only look at the fact that before some time there is one person and afterwards, two. Sullivan says he had a fifty-fifty chance of being in the new body, but I disagree. The Sullivan that went in to be scan was 100% guaranteed to come back out the same person, and he was 100% guaranteed to wake up in his new robotic body.
It’s almost as if, to wrap our heads around it, we picture there always being two people, who at some point just get split up into two bodies. One goes into Body A, the other into Body B, with a fifty-fifty chance of getting either particular one.
But before the split, there is only one person, and he will go into both Body A and Body B. There’s no chance involved. Sure, after that point, the world lines of the two copies diverge and are two different people, but they do not just share their history, they have the same history. The same family, the same ex-girlfriends, the same credit history, etc.
You may want to argue that the original physical body takes precedence, and the copy is a fundamentally new person, who never grew up in the suburbs, who never had a first kiss, and who never had to pay a bill (yet). You may have a point, but you can easily imagine a different situation (as McMahan does in his book) where not just the mind is copied into a robot but the original body is completely duplicated into two new copies, biological systems and all, and is destroyed in the process. Each version has equal claim to being the original, calling the other a copy (or, each have no claim at all). We just have no intuition to reconcile ourselves with the fact that two people were earlier the same single individual. Do you have any more claim to having been born from your mother than your brother does?
As always, it boils down to viewing the bigger picture (not just what the case is at two separate times), with a healthy does of my own prejudice about the unimportance of time. It’s just a dimension like any other.
The moral of the story is that if I ever have my mind duplicated into a robotic body, don’t ask which one is the original, because we both are. If you do, I’ll probably just bore you to death with philosophical ramblings.