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
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.
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.
Why did you find the analogy convincing? It doesn't look like a good analogy:
... (read more)It's cherry picked: erasing information from hard drives is hard, because they are very stable information storage devices. A powered down hard drive can retain its content for at least decades, probably centuries if the environmental conditions are good. Consider a modern DRAM chip instead: power it down and its content will disappear within seconds. Retention time can be increased to days or perhaps weeks by cooling to cryogenic temperatures before power down, and after the data has become unreadable by normal means, specialized probes and microscopy techniques could in some cases still retrieve it for some time, but ultimately the data will fade. It's unlikely than any future technology will be ever able to recover data from a RAM chip that has been powered down for months, even if cryogenically stored. Of course brains are neither RAM chips nor hard drives, but the point is that having high data remanence is specific to certain technologies and not some general propert
There's another problem with the hard drive analogy - he's comparing the goal of completely erasing a hard drive to erasing just enough of a person for them to not be the "same" person anymore.
With the kind of hardcare hard drive erasing he talks about, the goal is to make sure that not one bit is recoverable. If the attacker can determine that there may have been a jpeg somewhere at sometime, or what kind of filesystem you were using, they win.
The analogous win in cryonics would be for future archeologists to recover any information about who you were as a person, which orders of magnitude easier than doing a near-complete reconstruction of the algorithm-that-is-you.
It is important to realize that the moment you sign up for cryonics and the advancements made thus far are not the ones that you are likely to be subject to. While current practices may well fail to preserve usable identity-related information (regardless of experts opinions on whether or not this is happening (if it were known now, we could know it)), advancements and research continue to be made. It is not in your best interests to be preserved as soon as possible, but it is in your best interests to sign up as soon as possible, to ensure eventual preservation. Too often I see people basing their now-decisions on the now-technology, rather than the now-measured rate of advancement of the technology. The condition of, "If I'm going to be dieing soon," is simply not likely enough that most of us should be implicitly considering it as a premise.
To answer this question we should talk to lots of neuroscientists. Here's one:
... (read more)"When all you need to see it's bullshit is an undergraduate-level understanding of biology" is an extremely clear cue that the speaker does not understand the current state of the cryonics debate and cannot be trusted to summarize it. Anyone who does not specifically signal that they understand the concept of information-theoretic death as mapping many cognitive-identity-distinct initial physical states to the same atomic-level physical end state is not someone whose summaries or final judgment you can possibly reasonably trust. If they cite sources you might look at those sources, but you're going to have to figure out on your own what it means.
The basic idea of getting cryonics is that it offers a chance of massively extended lifespan, because there is a chance that it preserves one's identity. That's the first-run approximation, with additional considerations arising from making this reasoning a bit more rigorous, e.g. that cryonics is competitive against other interventions, that the chance is not metaphysically tiny, etc.
One thing we might make more rigorous is what we mean by 'preservation'. Well, preservation refers to reliably being able to retrieve the person from the hopefully-preserved state, which requires that the hopefully-preserved state cannot have arisen from many non-matching states undergoing the process.
The process that squares positive numbers preserves perfectly (is an injection), because you can always in theory tell me the original number if I give you its square. The process that squares real numbers preserves imperfectly but respectably since, for any positive output, that output could have come from two numbers (e.g. 1^2=1=(-1)^2). Moreover, if we only cared about the magnitude (modulus, i.e. ignoring the sign) of the input, even squaring over real numbers would perfectly preserve what we cared a... (read more)
Susskind's Rule of Thumb seems worthwhile here. The actionable question doesn't seem to be so much "Does Bostrom publicly say he thinks cryonics could work?" as "Is Bostrom signed up for cryonics?" (Hanson, for example, is signed up, despite concerns that it most likely won't work.)
Good point. In fact, Sandberg, Bostrom, and Armstrong are all signed up for cryonics.
I'd say it's more that a rich person not signing up is expressing a strong preference against. For people who believe rich people are smarter than average this should constitute a substantial piece of evidence.
Imagine people buying a car where it costs $1,000,000 to change the colour. We conclude that anyone who pays cares strongly about the colour; anyone who doesn't pay we can only say their feelings aren't enormously strong. Conversely imagine it costs $100 to change the colour. Then for anyone who pays we can only conclude they care a bit about the colour, while anyone who doesn't pay must be quite strongly indifferent to the car's colour.
I don't believe any of the various purely computational definitions of personhood and survival, so just preserving the shapes of neurons, etc., doesn't mean much to me. My best bet is that the self is a single physical thing, a specific physical phenomenon, which forms at a definite moment in the life of the organism, persists through time even during unconsciousness, and ceases to exist when its biological matrix becomes inhospitable. For example, it might be an intricate topological vortex that forms in a (completely hypothetical) condensate of phonons a... (read more)
I don't believe any of the various purely literary definitions of narrative and characterization, so just preserving the shapes and orderings of the letters of a story, etc., doesn't mean much to me. My best bet is that a novel is a single physical thing, a specific physical phenomenon, which forms at a definite moment in the printing of a book, persists through time even when not read, and ceases to exist when its physical form becomes illegible. For example, it might be an intricate topological vortex that forms in a (completely hypothetical) condensate of ink and/or paper, somewhere between the front and back cover.
That is just a wild speculation, made for the sake of concreteness. But what is really unlikely is that a novel is just a collection of letters, in the sense of orthography - a sequence of glyphs representing letters that are coarse-grainings of the actual microphysical states, and which can survive to be read on another, physically distinct medium, so long as it reproduces the sequence of letters of the original.
Physically, what is a novel? Nuclei and electrons. And physically, what is a story? It is an extreme abstraction of what some of those nuclei and electrons a... (read more)
A thread sprung up here about self-funding your cryonics arrangements. This has important enough practical implications for cryonicists that I am responding to it at the top level.
In addition to my original arguments that most individuals should not self-fund...
- Creditors and heirs will find it easier to raid you
... (read more)If I remember right the chance of it rescuing you were estimated to be somewhere between 10-20% by senior LessWrong people in the last census.
The interesting thing was that senior LessWronger were more likely to recommend people to undergo cryonics then less senior people when both believed in the same probability of being revived.
In the end the question is:
p(getting revived) * u(utility of getting revived) <? u(utility cost of acor payments)
It may be that people cryopreserved today will not be among the 'first batch' of people revived. The damage caused by ice could be repairable, but it might require more advanced nanotech, and perhaps some 'filling in' of lost information. I wouldn't be surprised if frozen people were revived in batches, starting from the most recently frozen ones, finally ending with those frozen in the 20th century.
One way that patternists could be wrong and I might still be satisfied with a (non destructive) upload or copy as a way to preserve myself is if our memories were prevented from diverging by some sort of sync technology. Maybe it would be a daily thing, or maybe continuous. Sort of a RAID array of brains.
But this still requires actual revival as an initial step, not destructive copying or uploading.
I wish I could give you more up-votes for explicitly making existential catastrophe part of your calculations, too many people focus on the technical considerations to the exclusion of other relevant unknowns.
Here are mine (explanation of edit-- oops, patternists being wrong and right didn't sum to 1, fixed now):
Cryo
(50% not being ended by an intervening existential catastrophe) x
(80% fellow humans come through) x
[(70% patternists are wrong) x (50% cryo sufficient to preserve whatever it is I call my continuity strictly by repairing my original instance) ... (read more)