Looking for opinions of people like Nick Bostrom or Anders Sandberg on current cryo techniques

ChrisHallquist

In June 2012, Robin Hanson wrote a post promoting plastination as a superior to cryopreservation as an approach to preserving people for later uploading. His post included a paragraph which said:

We don’t actually know that frozen brains preserve enough brain info. Until recently, ice formation in the freezing process ripped out huge brain chunks everywhere and shoved them to distant locations. Recent use of a special anti-freeze has reduced that, but we don’t actually know if the anti-freeze gets to enough places. Or even if enough info is saved where it does go.

This left me with the impression that the chances of the average cryopreserved person today of being later revived aren't great, even when you conditionalize on no existential catastrophe. More recently, I did a systematic read-through of the sequences for the first time (about a month 1/2 ago), and Eliezer's post You Only Live Twice convinced me to finally sign up for cryonics for three reasons:

It's cheaper than I realized
Eliezer recommended Rudi Hoffman to help with the paperwork
Eliezer's hard drive analogy convinced me the chances of revival (at least conditionalizing on no existential catastrophe) are good

But then Paul Crowley pointed out to me that what I posted yesterday about trusting experts seems to imply I should take cryonics less seriously than I do. I thought about it awhile, and realizes that I suspect that even among academics who would be predisposed to take cryonics seriously, say attendees at the workshop that produced the Whole Brain Emulation roadmap, Robin's more cautious perspective is probably more typical. Or is it? I've tried to find information online, and the one thing I've found is the Scientists' Open Letter on Cryonics, which carries this disclaimer:

Note: Signing of this letter does not imply endorsement of any particular cryonics organization or its practices. Opinions on how much cerebral ischemic injury (delay after clinical death) and preservation injury may be reversible in the future vary widely among signatories.

I don't find that terribly encouraging. So now I'm back to being pessimistic about current cryopreservation techniques (though I'm still signing up for cryonics because the cost is low enough even given my current estimate of my chances). But I'd very much be curious to know if anyone knows what, say, Nick Bostrom or Anders Sandberg think about the issue. Anyone?

Edit: I'm aware of estimates given by LessWrong folks in the census of the chances of revival, but I don't know how much of that is people taking things like existential risk into account. There are lots of different ways you could arrive at a ~10% chance of revival overall:

(50% chance of no existential catastrophe) * (30% chance current cryopreservation techniques are adequate) * (70% chance my fellow humans will come through for me beyond avoiding existential catastrophe) = 10.5%

is one way. But:

(15% chance no existential catastrophe) * (99% chance current cryopreservation techniques are adequate) * (70% chance my fellow humans will come through for me beyond avoiding existential catastrophe) = ~10.4%

is a very similar conclusion from very different premises. Gwern has more on this sort of reasoning in Plastination versus cryonics, but I don't know who most of the people he links to are so I'm not sure whether to trust them. He does link to a breakdown of probabilities by Robin, but I don't fully understand the way Robin is breaking the issue down.

In June 2012, Robin Hanson wrote a post promoting plastination as a superior to cryopreservation as an approach to preserving people for later uploading. His post included a paragraph which said:

We don’t actually know that frozen brains preserve enough brain info. Until recently, ice formation in the freezing process ripped out huge brain chunks everywhere and shoved them to distant locations. Recent use of a special anti-freeze has reduced that, but we don’t actually know if the anti-freeze gets to enough places. Or even if enough info is saved where it does go.

It's cheaper than I realized
Eliezer recommended Rudi Hoffman to help with the paperwork
Eliezer's hard drive analogy convinced me the chances of revival (at least conditionalizing on no existential catastrophe) are good

Note: Signing of this letter does not imply endorsement of any particular cryonics organization or its practices. Opinions on how much cerebral ischemic injury (delay after clinical death) and preservation injury may be reversible in the future vary widely among signatories.

(50% chance of no existential catastrophe) * (30% chance current cryopreservation techniques are adequate) * (70% chance my fellow humans will come through for me beyond avoiding existential catastrophe) = 10.5%

is one way. But:

(15% chance no existential catastrophe) * (99% chance current cryopreservation techniques are adequate) * (70% chance my fellow humans will come through for me beyond avoiding existential catastrophe) = ~10.4%

I don't think the question of whether you're the same person when you wake up as when you went to sleep [..] is meaningful.

I'm content to say that, though I'd also be content to say that sufficient loss of faculties (e.g., due to a stroke while I slept) can destroy my identity, making me no longer the same person. Ultimately I consider this a question about words, not about things.

Do [your faculties] change without there being any physical change?

Well, physical change is constant in living systems, so the whole notion of "without physical change" is somewhat bewildering. But I'm not assuming the absence of any particular physical change.

I can make them as similar as I like and they will never become the same! And so it goes with people.

Sure, that's fine. I don't insist otherwise.

I just don't think the condition you refer to as "being the same person" is a condition that matters. I simply don't care whether they're the same person or not, as long as various other conditions obtain. Same-person-ness provides no differential value on its own, over and above the sum of the value of the various attributes that it implies. I don't see any reason to concern myself with it, and I think the degree to which you concern yourself with it here is unjustified, and the idea that there's some objective sense in which its valuable is just goofy.

So while your doppelgänger might have the same faculties as you, it doesn't make him the same human being as you, and, unlike you, he wasn't the person who did X on your nth birthday, etc, and no amount of tinkering will ever make it so.

Again: so what? Why should I care? I don't claim that your understanding of sameness is false, nor do I claim it's meaningless, I just claim it's valueless. OK, he's not the same person. So what? What makes sameness important?

To turn it around: suppose I am informed right now that I'm not the same person who did X on Dave's 9th birthday, that person died in 2012 and I'm a duplicate with all the same memories, personality, etc. I didn't actually marry my husband, I didn't _actually_buy my house, I'm not actually my dog's owner, I wasn't actually hired to do my job.

This is certainly startling, and I'd greet such a claim with skepticism, but ultimately: why in the world should I care? What difference does it make?

Perhaps that is the scenario you prefer, but, you're quite right, I find it very odd.

Prefer to what?

So, as above, I'm informed that I'm actually a duplicate of Dave.

Do I prefer this state of affairs to the one where Dave didn't die in 2012 and I was never created? No, not especially... I'm rather indifferent between them.

Do I prefer this state of affairs to the one where Dave died in 2012 and I was never created? Absolutely!

Do I prefer this state of affairs to the one where Dave continued to live and I was created anyway? Probably not, although the existence of two people in 2013 who map in such detailed functional ways to one person in 2012 will take some getting used to.

Similarly: I am told I'm dying, and given the option of creating such a duplicate. My preferences here seem symmetrical. That is:

Do I prefer that option to not dying and not having a duplicate? No, not especially, though the more confident I am of the duplicate's similarity to me the more indifferent I become.
Do I prefer it to dying and not having a duplicate? Absolutely!
Do I prefer it to having a duplicate and not-dying? Probably not, though I will take some getting used to.

Which of those preferences seem odd to you? What is odd about them?

The preferences aren't symmetrical. Discovering that you're a duplicate involves discovering that you've been deceived or that you're delusional, whereas dying is dying. From the point of view of the duplicate, what you're saying amounts to borderline solipsism; you don't care if any of your beliefs, memories, etc, match up with reality. You think being deluded is acceptable as long as the delusion is sufficiently complete. From your point of view, you don't care about your survival, as long as somebody is deluded into thinking they're you.