X-Message-Number: 19935
Date: Wed, 28 Aug 2002 14:29:33 -0400
From: Jeffrey Soreff <>
Subject: Re: Probabilties

>Message #19891
>Date: Sat, 24 Aug 2002 08:17:10 -0700
>From: "Ralph C. Merkle" <>
>Subject: Re: Probabilties 
>My own estimates of the probability of success of cryonics have 
>consistently been above 50%.
>Particularly with the new vitrification methods that Alcor is using, it 
>should be clear that information loss caused by the suspension technology 
>is an unlikely cause of information theoretic death (see 
>http://www.merkle.com/cryo/techFeas.html#CRITERIA for a discussion of 
>information theoretic death).
>Iatrogenic death (caused by the behavior of doctors) appears to be the 
>dominant risk factor at the present time. Refusal to initiate suspension in 
>a timely fashion is the primary problem. Various estimates of the risk can 
>be made, based on the amount of delay and the expected information loss 
>mechanisms (discussed at 
>http://www.merkle.com/cryo/techFeas.html#ISCHEMIA). I think that, despite 
>the delays, information theoretic death is not a high probability event 
>even at present (see http://www.merkle.com/cryo/cryptoCryo.html for a 
>discussion of one reason for believing that a higher probability of success 
>than might generally be accepted is actually justified).
>The next most likely failure mechanism is premature rewarming.  This might 
>be secondary to earthquake, fire, riots, organizational failure, etc. 
>Alcor's site was chosen to minimize these and other failure mechanisms, and 
>experience to date suggests these failure mechanisms can be minimized.
>Finally, there is the risk that technologies that are feasible in principle 
>are never developed and applied in practice. This risk seems negligible. 
>Development of nanotechnology and its medical applications in a period of 
>decades seems overwhelmingly likely. Mechanisms that might prevent such 
>development seem limited to civilization-destroying catastrophes -- which 
>at present appear to have a low probability.  The risk that such 
>technologies (which would be inexpensive) would be available but not 
>applied correlates almost exactly with the risk of premature rewarming, 
>dealt with above. Why bother keeping someone in liquid nitrogen if you can 
>revive them at some reasonable cost?
>Given the increasing acceptance of physician assisted suicide, it seems 
>likely that physician assisted cryonic suspensions will become legal at 
>some point in the future. If it's legal to commit suicide, it should surely 
>be legal to try and save your own life. Such a development should 
>significantly reduce iatrogenic deaths.
>    Ralph C. Merkle
>    www.merkle.com
>>Message #19872
>>Date: Thu, 22 Aug 2002 11:35:32 -0400
>>From: Jeffrey Soreff <>
>>Subject: Re: Probabilties
>>I also think that the overall probability estimate _does_ matter.
>>We all allocate our resources amongst various goals and subgoals,
>>and our best guesses about the odds of success for various courses
>>of action affect what allocations look sensible.  In my own position,
>>cryonics looks sensible to me if the odds of success are better than
>>about 1% (from, roughly speaking, comparing a year's vacation with
>>the net present value of an indefinitely long future, discounted at
>>1%/year).  My estimates of the odds of being revived tend to come
>>out in the 2%-10% range (with huge error bars, of course).  If I
>>thought the odds were ~>50% I'd be much more actively trying to
>>persuade friends and family members.  If I thought the odds were
>>well below a chance in a thousand I wouldn't have signed up.

Many thanks!  In terms of Steve Harris's Markov chain,
here is roughly how my guesses go:

P1: Probability that your memories will survive your cardiac arrest until
the cryonics organization can reach your side and get your brain cool.


I am not looking so much at the probability of _provable_ information
theoretic death here, but rather what are the current odds of "bad"
cryopreservations, e.g. > 1 hour delays, with attendant ischemia.
Roughly speaking, I think that cryonics will continue to be a
"shoestring" operation, and that the cases which will really get
revived will be the easy ones. (see also P3b & P3c below).  I agree
that iatrogenic delay is the major factor today, and that this factor
could be cut a great deal.

P2: Probability that your memories will then survive cryoprotectant solution
and vitrification in liquid nitrogen.


Clean fractures don't lose information.

P3: Probability that eventually molecular repair technology will be invented
that is capable of restoring humans, memory intact, when damaged this badly

general purpose molecular manufacturing, 75% (perhaps higher)
(Though current experimental efforts seem directed mostly at
special purpose systems without positional control :-( )

P4: Probability that society will survive development of that technology

25% (depending on what is meant by "society") - I think
the likeliest outcome of nanotech development is
competing organizations using AIs in ways that ultimately
displace humans, replacing them with non-upload AIs.
In other words, I think that a likely future is one where
chucks of human culture, e.g. Maxwell's equations, is still
known and in use a thousand years from now, but the
entities using it do not incorporate the unwritten memories
of any human individuals.

applications of nanotech for neurological repair
for common conditions, e.g. stroke, 

90% (depending on how hard the problems are)
This is the conditional probability, given P3a & P4.
All of the odds from this point on are in a hypothetical
future where full MNT has been developed, including
massive CPU power, but human desires continue to
dominate the world - perhaps because AI turned out to
be much harder to develop than expected, perhaps
because "Friendly" AI was successfully developed
(the less likely branch, in my guesswork).

P5: Probability that your cryonics organization will survive that long, as
well as you with it (these can be slip into sub probabilities if you like).

50% (depending mostly on how long this takes, general economic churn etc.)
This risk increases slowly over time, even in benign economic
and political conditions.  This is basically the rewarming factor
in your analysis.

application of nanotech specifically for repair of freezing damage:

50% (depending on whether solving the _specific_ problem of freezing
damage can be done "on a shoestring" given massive CPU power but
without AIs)  This is basically the "feasible in principle, but not
put into practice" factor in your analysis.

P6: Probability that anybody in the best of futures, will be interested,
resourceful, and nice enough to use the technology on you.

100% (given P5)

P7: Probability that you'll then be allowed to live a life that would be
more acceptable to you than being dead.

100% (given P3a, P4, P5)

                           Best wishes,

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