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Comment by tritium | Hacker News Reader

Identical twins handily prove that copying a brain still produces different people.

It’s true for siamese twins, and it’d be just as true for cloned genetic stem cells 3D printed from a snapshot of the exact cellular structure of your brain from a moment in time, transplanted into your body.

If I copy your brain, you won’t be inside it, even if it’s effectively you, as far as anyone else can tell.

So, I can comfort myself with a replica of each dead parent. But the parents that raised me, those people are dead. They won’t be there to see me sharing christmas with their atomic-precision duplicates.

Virtual simulations aren’t people, aren’t human beings, no matter fidelity of the simulation. Maybe you can hold a conversation with a hologram, but then what?

Would one expect to experience what it feels like to become and persist as a haptic-enabled hologram? Pretty sure that’s a bogus concept, turtles on down.

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Why do you assume that identical twins have identical brains?

Brain physical structure is altered during lifetime experience, learning changes large physical properties of neurons e.g. forming some new synapses and pruning others.

Even at birth, identical twins have different fingerprints, different retinas and yes, different cellular structures of their brains. And that only diverges later.

It's not a given that a brain "3D printed from a snapshot of the exact cellular structure of your brain" would be sufficiently good copy, we know that there are other things that matter (e.g. various intra-cell properties and chemical concentrations within particular locations of those neurons) and there likely are some other things that matter but which we don't know yet.

However, assuming that we could make a sufficiently good copy, it would be undistinguishable from you. It would have the same behavior, reactions, memories, skills and understanding; it would have the same beliefs as you do - including a belief that it's you and that it has been you since your birth, supported by memories of living your life. If the copy is sufficiently good, barring the signs of the operation itself (scar tissue? machinery? video evidence of it being done) neither your relatives nor (new?) you yourself would be able to make a distinction.

Yes, you could argue that the new copy is different from the previous one, that it's not the same, that it lacks continuity. But that's arguing about what do we mean when we say "the same". If you didn't know that your parents had died, you'd have no way to tell when their copies come to celebrate christmas with you.

Suppose someone invented a "matter transporter", that was to all external appearances approximately equivalent to the standard device that is a science fiction trope.

But what actually happens with this device, is that once a person steps into the chamber, and is scanned, and the information to recreate them is sent to a receiver elsewhere, by some beaming method, the original is dropped into a "recycling chamber" where their body is shredded, compacted, and made into soylent green or something.

Would you voluntarily use this device? All the people who go through it report at the other end everything went well, since it in fact makes perfect copies.

One tangential idea I also want to mention is that there is a mental disorder where people perceive things incorrectly as false and strange. So, given your scenario of your parents coming to Christmas, there exists a disorder where your brain tells you they are some sort of duplicates or imposters, but you can't explain why. I don't have a reference offhand, but it's probably either something I read in a book by the neurologist Oliver Sacks, or some book about schizophrenia.

There’s something circular about this argument, which reduces to “We can’t make perfect copies. But if we could, they’d be perfect.”

Without evidence - unlikely anytime soon - there’s no way to know if a copy really would feel identical, or whether - more likely IMO - it might start “close enough” but errors would accumulate over time and lead to noticeable differences, which might be experienced in both subjective and objective ways.

If there are quantum-level effects, consciousness will not be copyable.

Even if there aren’t, we’re talking about exactly duplicating a specific arrangement of atoms in space to reproduce all the neuronal configurations and chemical gradients.

And we’re talking about doing that with no significant errors. And implanting that configuration inside an extended nerve and tissue network it has to be matched to.

At the very least, the functional information structures created by the chemistry and biology have to be duplicated exactly - probably instantaneously, to avoid mistakes - with no significant inaccuracies.

All of that seems quite challenging to me.

I wonder if person died, and his clone waking up can be compared to a person getting into a deep coma from an accident and waking up a year later. In both cases a consciousness disintegrated and a consciousness was integrated?

> clone

Being genetically identical is not equivalent to having same memories and experiences. Such things are not stored in DNA.

Would you commit suicide to find out?

Would you believe it, if you witnessed a minutes-long, violent, extremely painful suicide, and the dead individual’s clone said they remember everything, and that despite all the screaming and begging, it was an unremarkable experience?

I wouldn't get into a deep coma to find out either!

>If I copy your brain, you won’t be inside it, even if it’s effectively you, as far as anyone else can tell.

If you wake up tomorrow, will you be inside of your brain, even if it's effectively you, as far as anyone else can tell?

What if your awareness is reconstructed daily from the structure of your synapses? If you copy that structure, that copy is you, in the same way that you are now almost the same person as the one that went to sleep yesterday. (Quite like the movie 'The Prestige'.)

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