They implicitly claim that not only is the chance non-zero, but that it's large enough to be worth the opportunity cost of actually freezing people. I agree that a non-zero chance seems obvious, but this claim definitely does not, and needs a lot more substantiation than there actually is.
It is true that chances can't just be "non-zero" and be rational, nor simply based on faith, because that's basically Pascal's Wager. However I think my 1-10% gut feeling is something that I could probably be talked out of if it were really arbitrarily low like people keep assuming.
Assuming that probability range, I think selling to ordinary people is pretty defensible at $50k-$500k rates, because we already spend around $5M to avoid accidental deaths via regulatory tradeoffs. If it is lower (0.1% say) and yet still not arbitrarily low, we would then need to restrict to either very rich or very desperate people (where the ratio of marginal utility of life to marginal utility of a dollar differs significantly from the norm). Arbitrarily low chances literally on level with egyptian mummification or worshipping a random god is definitely not something that should be sold to anyone (except as a novelty maybe).
Note also that cryonics storage cost is influenced by economies of scale, so mass-produced cryonics is likely to be a lot less expensive per person than the cost you see on the market today. If you could seriously measure a non-arbitrary 0.01% it wouldn't necessarily be impossible to justify even on the mass market and even to relatively death-complacent people -- it would just have to be very cheap for them. Granted, gut feelings are hard to calibrate well to reality at such extremes (hence lottery tickets) so I'm not going to seriously argue that, I'm just saying this to give you a feel for why I think there's a need for fairly strong counterargument before you can reasonably take the position that cryonics is just innately bad/fraudulent business.
I also anticipate various positive externalities from the cryonics business, such as sooner (eventual) development of suspended animation of the damage-free variety, which has potential to save a lot of lives and spare a lot of suffering. These too should be accounted for as part of a robust criticism.
You can look it this way: life after rewarming can last for hundreds of years, easily a thousand as medical technology will have advanced at that point. People are currently willing to pay $100k in medical bills to extend their life by about one year with 50% chance, which means that the cost is $200k per year.
Cryopreservation also costs about $100k (slightly more in real life I guess, I'm rounding numbers for simplicity).
If cryopreservation has a 1% of success to extend life by 1000 years for $100k, then they will "buy" 1 year for $10k. Of course, you can change the numbers (in any direction), e.g. 100 years of life would come out to $100k per year, still cheaper than what most people are willing to pay today to live slightly longer. The 1% success rate is rather pessimistic, too.
If you take quality of life into consideration, the argument starts to favour cryonics quite heavily (we can assume that life is a lot better in the future thanks to advancement of technology).
Where do you get that? From what little I understand, 1% seems highly optimistic, given how destructive the freezing process is at the moment.
I'm just emphasizing that this technology is not a realistic solution to anything, just as a lottery ticket is not a solution for one's financial problems. I may choose to buy a lottery ticket myself, same as I may choose to have my head frozen, but I'm not going to consider this as a real solution to any problem - just like a lottery ticket, it may have more "entertainment" value than real value (though the "entertainment" value may be enough for me to buy it).
My only point is that we should always see the difference between "lottery tickets" and real solutions, and always see the former as what they are: hope growing "entertainment" forms... I know, most people don't like this way of looking at things and label it "dark and gloomy", but it's how I see it :)
As we're using analogies: we know that machine-flight is possible. But how many people broke their legs after gluing feathers to wings strapped to their arms and jumping off a barn, flapping wildly, before Kitty Hawk flew?
I am all for keeping a bit of hope alive, but a non-zero chance argument on its own is not enough. What is the probability exactly, can it be proven.
The "non-zero" argument can be fixed simply by comparing relative likelihoods, or noting that while one can't ever rationally believe with 0% probability, you can use epsilon as a substitute for "it's more than 0 but I can't measure how much because it's so small". Personally I think there's enough evidence to put religious ideas of afterlife far below the probability of a single sha256 hash resulting in a new block in the bitcoin blockchain: http://blockexplorer.com/q/probability
Actually, you can get away with assigning anything you want. That's hidden in the assumption that the criteria he lists are more-or-less independent.
> You might have a different list of criteria or different probabilities, but the point is to lay them down and give a reason why you think it's unlikely enough not to pay the small sum of money.
You've got the burden of proof backward. The cryonics advocates are the ones trying to argue that cryonics will work with sufficiently high probability to make investing in it worthwhile. The grandparent cited 5% as if that figure had even one significant digit -- which it doesn't, by Hanson's own calculation.
> It also lets others argue with you over your estimates, because they might have information you don't, now or in future years.
It also lets others argue even if they don't have new information, which just wastes everyone's time. The same phenomena also occurs with the Drake equation.
Cryopreservation advocates do not claim that the process is proven to be work, they claim that the chance may be small, but it's non-zero.
>"Nature"/"The universe"/"God" is NOT on our side on this path, so there's no room for optimistic thinking, we can only rely on cold (literally) hard science and math!
I don't even know where you're going with this discourse. If you're a utilitarian rationalist you can estimate the chance of success for cryopreservation and revival. It's quite easy to show that if the probability is non-zero, then it's beneficial to make such a bet, as the possible positive utility can be huge if the cryopreservation is succesful.
If you think that probability estimates are "not science" and therefore "irrational", you don't know what you're talking about. If you think that current scientific evidence shows that the chance of revival is zero, then you're clearly wrong (and that would contradict your own claims, as zero chance would mean there's no need to make any new experiments).