Thoughts on cryonic preservation & revival

[lproven]

This is a rather long reply to a post from ciphergoth. The question being, is it plausible that, in future, we will be able to resurrect people from their head, cryonically frozen post-mortemI am keenly interested in the prospect of whole-brain emulation, which strikes me as potentially plausible, with reasonable probability. For one thing, I think that this

Comments

[zotz]

Something that occurred to me a while after reading the good Mr Crowley's thoughts on the matter seems to be confirmed (FSlimitedVO) by thee ackurssed Witchipedia:

Research has suggested that long term memory storage in humans may be regulated by DNA methylation.

That's a real oh-shit problem in my view - getting all the methyl groups right on the dna of at least a good proportion of someone's neurons strikes me as showstopper. DNA methylation not being involved in brain functioning would make the data extraction much easier.

[lproven]

That sort of detail is an area I know next-to nothing about, but I am currently doing some reading in the broad area...

Wouldn't surprise me if you're bang on, though!

[ciphergoth]

Interesting. Is the issue information-theoretic death before you're in the dewar, or a scanning issue?

[zotz]

That one's a scanning issue. Methyl groups are added to individual DNA bases and affect gene expression. They're fairly stable . . . but there are awful lot of potential sites per cell and a lot of neurons, and distinguishing a methylated base from an unmethylated one isn't a trivial task.

[ciphergoth]

Hmm, thanks! Are you saying "seems a long way away from where we are now" or "could easily stay unsolved even given centuries of scientific and technological progress"?

[ciphergoth]

I'm out of my depth here, so I'm glad of any expertise I can lay my hands on - why do these numbers pose problems even for nanobots?

[reddragdiva]

But nanobots!!

[reddragdiva]

NANOBOTS!!!!

My theory is that CryoNet is in fact entirely populated by nanobots.

[ciphergoth]

10^21 is certainly a pretty stupendously large number, and I definitely agree that uploading will be a lot easier if it turns out that we can read what we need to know entirely from morphology. But I thought that one of the things that people liked about nanobots was that you could anticipate eventually manufacturing them in very large numbers. If you can make a few trillion of them, each one only has to read a few hundred billion bases. That's a lot of data to process, but obviously if you have nanotech you can build some pretty powerful computers, so it seems like I'm still not properly understanding your objection.

[zotz]

They still use energy (see the above-mentioned "vapourising-your-head" caveat) and have an error rate. See also, of course, Maxwell's Demon, which surely has to be the prototypical nanobot.

[ciphergoth]

What might be an acceptable error rate? Plucking a figure out of the air, I would have guessed that an error rate of, say, 10^-9 would be both achievable and sufficient, but are my intuitions totally out of whack about this?

The energy thing sounds like a much bigger concern; would be interested to see some numbers around that one.

[zotz]

I would have a lot more time for cryonics discussion if so much of it didn't seem to consist of convenient figures and ideas hopefully discovered in the aerial environment. Given fidelity figures for biological systems, I'd guess you were at least 3 to 6 orders of magnitude out there. At least.

Have you read discussions of why Maxwell's Demon couldn't work?

[ciphergoth]

if so much of it didn't seem to consist of convenient figures and ideas hopefully discovered in the aerial environment. As I understand it, there are people who do know what they're talking about here, I'm just not one of them...

Yes, I've read about Maxwell's Demon - that argument applies here?