Paul Crowley here.
I am signed up for cryonics and I'd encourage others to do likewise. My comments on Twitter were meant as a caution against a naïve version of the expert opinion principal. As you can see, I've worked very hard to find out whether expert dismissal of cryonics is on expert grounds, or on ill thought out "silliness" grounds combined with a lingering supernatural idea of death. The evidence I currently have points overwhelming at the latter. To me this poses a problem not for cryonics but for how to make the best use of expert opinion.
Assuming a good future, I'd put the chances of revival through scanning and emulation at over 50%. For the cryonics process to do so much damage that there's no way for us to infer the lost information given full-blown neural archaeology, Nature would have to surprise us.
I'm curious to know what you think a "naive" version of the expert opinion principle is, and what a less-naive one would be.
After thinking about this beyond my comments on Twitter, one issue is that judgments about cryonics aren't just judgments about cryonics - they're about future technology that could be used to revive / upload cryopreserved people. I think I'd expect biologists (esp. neuroscientists and cryobiologists) to be trustworthy on current preservation techniques, but few will have anything approaching expertise about future technology.
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:
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:
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:
is one way. But:
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.