Transferring consciousness

[Saria]

I'm pretty sure there's something to do with quantum mechanics which means it's actually impossible to make an absolute duplicate of anything ever. A copied individual would be it's own being, you can only measure one aspect of any one thign at a time. Wish I remember where it was I saw that.

What you mean by that is probably the 'no-cloning theorem', which states that it is impossible to make an identical copy of an unknown quantum state. Still, the brain is a macroscopic object, at least some of the stuff it does can be understood in a classical (i.e. not quantum sense) and consciousness/awareness clearly have some classical significance, even if they are ultimately generated by quantum phenomena. So, maybe there is a way around things, in the sense that probably you don't need a mapping of the evolution of every single quantum state in your head in order to understand (or duplicate) its behavior.

Although if consciousness is ultimately based on quantum states, while copying it exactly would be impossible, transferring it would be (relatively) easy... which would completely sidestep the problem Backdraft is worried about: you would be able to transfer your consciousness to a machine (or anything else you please) without dying in the process.

Of course, consciousness is probably not quantum states. So...



Has anyone here seen the film John Dies at the End? It has a hilarious opening bit about an axe. If you haven't seen it, the joke is based on the classic philosophical problem called the "ship of Theseus", which goes something like this:

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In order to preserve the historic ship of Theseus, the Athenians put it in a museum, and cared for it meticulously. But the wood, as wood does, started to rot over over time. As each plank rotted, the Athenians replaced it with a new, identical plank, so the ship itself stayed in good condition. But after a long enough time, it happened that every single plank had - at some point - rotted and been replaced with a new one.

So... was the ship in the ship in the museum the ship of Theseus?

And the bonus question added years later by Hobbes: Suppose each time a plank rotted and was replaced, a fan recovered the original plank, used some technique to "un-rot" it, then used all those discarded planks to build another ship. Is the ship in the museum the ship of Theseus, or is the one the fan has the ship of Theseus... or both or neither?

So why am I bringing it up? Well, however consciousness may "work", it seems indisputable that it is rooted in our brains somehow. You muck around with someone's brain - damaging it, or even just temporarily changing its chemistry - and you can change what a person experiences, how they think, and even who they are (personality-wise). And our brains - however they work - are molecules which are made up of atoms. It turns out that our bodies very regularly replace the atoms that make them up at an astonishing rate. Not all of the atoms in our body get replaced... but over a long enough period - say a couple years - so many of the molecules in your brain may have been replaced that that 99% of its atoms are different.

So because your brain's molecules may have been replaced in their entirety (or very near to it) multiple times over the course of your life... does that mean you've died multiple times? If so... when? How many times?

But if you haven't died, and you're still the same person continued on from the person you were, say, 10 years ago, then you believe it is possible to remain you and not die even if pretty much all of your brain is replaced. Which brings up an interesting puzzle.

Suppose you have a car that you really like and you won't let me drive it. While you're distracted, I sneak in and change one of the spark plugs. "Aha!" I gloat. "Now this car is no longer your car! So now I can drive it!"

But no, you'd surely say, it's still your car. I don't think anyone would argue that; in fact, it would be silly if you took your car in to a mechanic and they changed a spark plug and told you that it's clearly not the same car you drove in thus it's not your car.

So this time, while you're distracted, I replace a spark plug and one of the tires. "Now this isn't your car!" I say.

But no, you'd still say it's your car.

So now I replace all the spark plugs, all four tires, and one of the doors (with an identical replacement, of course).

Is it still your car? I think everyone would agree so.

So I replace all the spark plugs, the crankshaft, the pistons, all four tires, all four doors, and the windshield.

Still your car?

At some point, surely, I will have replaced enough parts of your car that its no longer your car, right? But... exactly when is that line crossed? 50%? And, if it is 50%, then suppose I replace 50% of your car with new parts... but take the old parts and use them with other parts to create another car? Which car is yours? Both? Neither?

What does all this have to do with the thread question? Well, here we go:

Suppose instead of doing a wholesale "copy" of your consciousness from your brain to a computer, I replace a single neuron in your brain with a computer chip. Have I killed you? Are you no longer "you"? I don't think anyone would say yes to either of those questions.

So the next day, I replace another neuron. Dead yet? No longer you? Again, I don't think anyone would think so.

So if I keep doing this, eventually (assuming you live long enough to swap out all ~100 billion neurons at a neuron per day) I will have replaced all the neurons in your brain with computer chips. At what point did you "die"? At what point did the person in front of me stop being "you" and become someone else - a copy of you?

And if you never die and remain "you" even though all of the atoms or neurons in your brain are replaced (by other atoms or by computer chips) over a period of time... then how long does that period of time have to be? Do you survive if your neurons are all replaced over the span of ten years but die if that happens in a year? A day? A nanosecond?



Here's now I figure it. Whatever consciousness is, it's in my brain. However my brain works, it's made up of cells, molecules, and atoms. Those cells, molecules, and atoms are replaced over and over... yet I'm still me. Even though the substrate of my consciousness is continually changing, repeatedly, somehow I persist.

Therefore, even if the substrate of my consciousness is changed to a computer system, somehow I will be able to persist. So if I am copied to a computer, it will still be me - it won't be that "I died and this is someone else". At the moment of copying, there will be two "me"s, one in the brain, one in the machine. Neither one will be more "me" than the other. We'll both be me. If I owned a car before the procedure, then the car would belong to both of those people after. And then those two people will start to diverge and become two different people, both of which will be continuations of "me" but will be independent of the other. When a tree trunk diverges into branches, it's silly to ask which branch is the real tree.

So after all that, I can finally answer the question.

Hell yeah, I'd do it.

But I don't see it as "killing" myself while someone else - a copy of me - lives on. If I get in the machine, go unconscious, then my mind-stuff is copied into a computer, and then the copied mind awakens in the system... then no one has died. "Me" was a mean-brain one moment, blinked, then "me" was a cyber-brain the next. At no point did it stop being me. Everything I knew, thought, felt, or loved persists in the cyber-brain. In what sense would that not be "me"?

(Alternatively, if meat-Saria went into the machine and had her mind copied so that the result was a meat-Saria plus a cyber-Saria, both would be "me". No one dies in that scenario either.)

Here's another thought experiment to consider. Suppose you went into the machine, had your consciousness copied to the computer... then copied back into the brain. Wouldn't that still be you? Did you die during that procedure and the person who walked out is someone else? And, if that happened... how would you know? You got in the machine, there was a flash, then you got out and the operator told you it didn't work. How would you know whether you'd been transferred at all or not? What would be different?