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%

A story in a book, versus a mind in a brain. Where to begin in criticizing that analogy!

I'm sure there's some really profound way to criticize that analogy, as actually symptomatic of a whole wrong philosophy of mind. It's not just an accident that you chose to criticize a pro-physical, anti-virtual theory of mind, by inventing a semantic phlogiston that materially inhabits the words on a page and gives them their meaning. Unfortunately, even after so many years arguing with functionalists and other computationalists, I still don't have a sufficiently nuanced understanding of where their views come from, to make the profound critique, the really illuminating one.

But surely you see that explaining how it is that words on a page have meaning, and how it is that thoughts in a brain have meaning, are completely different questions! The book doesn't think, it doesn't act, the events in the story do not occur in the book. There is no meaning in the book unless brains are involved. Without them, words on a page are just shapes on a surface. The experience of the book as meaningful does not occur in the book, it occurs in the brain of a reader; so even the solution of this problem is fundamentally about brains and not about books. The fact that meaning is ultimately not in the book is why semantic phlogiston is absurd in that context.

But the brain is a different context. It's the end of the line. As with all of naturalism's ontological problems with mind, once you get to the brain, you cannot evade them any further. By all means, let the world outside the skull be a place wholly without time or color or meaning, if that is indeed your theory of reality. That just means you have to find all those things inside the skull. And you have to find them for real, because they are real. If your theory of such things, is that they are nothing more than labels applied by a neural net to certain inputs, inputs that are not actually changing or colorful or meaningful - then you are in denial about your own experience.

Or at least, I would have to deny the basic facts of my own experience of reality, in order to adopt such views. Maybe you're some other sort of being, which genuinely doesn't experience time passing or see colors or have thoughts that are about things. But I doubt it.

I agree with almost all of what you wrote. Here's the only line I disagree with.

If your theory of such things, is that they are nothing more than labels applied by a neural net to certain inputs, inputs that are not actually changing or colorful or meaningful - then you are in denial about your own experience.

I affirm that my own subjective experience is as you describe; I deny that I am in denial about its import.

I want to be clear that I'm discussing the topic of what makes sense to affirm as most plausible given what we know. In particular, I'm no... (read more)