Archive for February, 2010

[A guest post from Doug Clow. This was a comment in this article on Bostrom and Sandberg’s Whole Brain Emulation: a Roadmap, but given its length and substance I am with permission putting it here as a new blog post.]

I too am short of time, but have given this paper a quick run through. Here are some unstructured and unedited quick notes I made while I was at it. Apologies for brevity and errors — I almost certainly missed some of their points and have misrepresented parts of their case.

It does seem to be a serious and reasonably well-informed piece of work on speculative science and technology. Emphasis on the speculative, though — which they acknowledge.

The distinction between emulating a brain generically (which I reckon is probably feasible, eventually) and emulating a specific person’s brain (which I reckon is a lot harder), and emulating a specific dead person’s brain (which I reckon is probably not possible), is a crucial one. They do make this point and spell it out in Table 1 on p11, and rightly say it’s very hard.

p8 “An important hypothesis for WBE is that in order to emulate the brain we do not need to understand the whole system, but rather we just need a database containing all necessary low‐level information about the brain and knowledge of the local update rules that change brain states from moment to moment.”

I agree entirely. Without this the ambitious bit of the enterprise fails. (They make the case, correctly, that progress down these lines is useful even if it turns out the big project can’t be done.) I suspect that this hypothesis may be true, but we certainly need to know a lot more about how the whole system works in order to work out what the necessary low-level information and update rules are. And in fact we’ll make interesting scientific progress – as suggested here – by running emulations of bits of the brain we think we might understand and seeing if that produces emergent properties that look like what the brain does. Actually they say this on p15 “WBE appears to be a way of testing many of these assumptions experimentally” – I’d be a bit stronger than that.

Table 2 on levels of emulation makes sense. My gut instinct (note evidence base) is that we will need at least level 8 (states of protein complexes – i.e. what shape conformations the (important) proteins are in) to do WBE, and quite possibly higher ones (though I doubt the quantum level, 11, is needed but Roger Penrose would disagree). Proteins are the actually-existing nanobots that make our cells work. The 3D shape of proteins is critical to their role. Many proteins change shape – and hence what they do or don’t do – in to a smallish fixed number of conformations, and we already know that this can be hugely important to brain function at the gross level. (E.g. transmissible spongiform encaphalopathies – mad cow and all that – are essentially caused by prion proteins in the brain switching from the ordinary shape to the disease-causing one.)

The whole approach is based on scanning an existing brain, in sufficient detail that you can then implement an emulation. I think that’s possibly useful, but I think a more likely successful route to a simulated (!) intelligence will be to grow it, rather than to bring it in to existence fully-formed. By growing, I mean some process akin to the developmental process by which humans come to consciousness: an interaction between an environment and a substrate that can develop in the light of feedback from that environment. But based on their approach, their analysis of technological capabilities needed seems plausible.

The one that leaps out as really, really hard (to the point of impossibility in my mind) is the scanning component. There is the unknown of whether the thing is doable at all (what they call scale separation), which is a biggy, but falsifiable by trying out experiments in this direction.

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For a change, here’s something that I hope those of you who disagree with me on cryonics can agree on — I think you would all agree that criticism of cryonics should be honest.

Stephen Barrett, M.D.’s QuackWatch (“Your Guide to Quackery, Health Fraud, and Intelligent Decisions”) has a page about cryonics, which places it firmly on the “quack” side. As evidence, they quote Michael Shermer’s Nano Nonsense and Cryonics:

Cryonicists believe that people can be frozen immediately after death and reanimated later when the cure for what ailed them is found. To see the flaw in this system, thaw out a can of frozen strawberries. During freezing, the water within each cell expands, crystallizes, and ruptures the cell membranes. When defrosted, all the intracellular goo oozes out, turning your strawberries into runny mush. This is your brain on cryonics.

But as regular readers know, this paragraph is entirely erroneous when it comes to cryonics practice. Shermer says as much himself.

I have sent six emails to Barrett and received two replies. The first was one of the many emails I sent to critics of cryonics asking for further reading; I accidentally lost track of who I had sent this to and so sent two such emails. Neither received a response. I later sent him a courtesy email advising him of my survey (since it mentions him), which garnered the response (in full) “Sorry, I am not interested in further involvement in your project”. I replied immediately to thank him for his time.

I then thought I should mention what Shermer had to say about the quote he uses on his website, and sent an email this morning linking to it. The response was (in full) “Kindly stop pestering me. ” I replied to that promising to “write up the outcome of this conversation” and send no further emails. (Of course, this means I now can’t alert him to this blog post — I should have thought of that before I sent it!)

Does anyone else think that using a quote to discredit cryonics which the author himself agrees is entirely misleading, and giving such short shrift to a brief polite email pointing this out, isn’t really in the spirit of scientific skepticism at its best?

OK, that’s enough on the technical side for now — here’s a space to talk about non-technical objections.

I think the strongest argument here is the relatively high danger of global catastrophe: that by some means or other, as a result of the very technological advancement that inspires cryonics, there will be some sort of global catastrophe that makes it impossible for cryonics firms to collect money from investments and/or buy liquid nitrogen with it. A climate change related catastrophe is one candidate, but there are all sorts of other existential risks to consider.

By far the best technical objection I’ve heard so far is David Matthewman’s comments here, discussing Bostrom and Sandberg’s Whole Brain Emulation: a Roadmap:

[…] I still wouldn’t get your hopes up. As far as I can see, it offers no way to discern the state of the neurons, and admits that while it might be possible to get the structure for a small slice of the brain, getting it in 5nm detail for the whole volume is currently impossible, with no known way to overcome the current technological limitations. Many of those limitations are imposed by the wavelength of the medium you’re scanning with, and there’s just no easy way round that. The speed of scanning (which is also currently a showstopper for the ~5nm technologies that might otherwise be attractive) might be able to be improved, but bear in mind that you’re working at levels where the energy of the electrons/photons that you’re using to scan risk damaging the sample, and using more of them in parallel may damage it more. The data transfer/storage problem probably is solvable, by contrast.

I find it a bit worrying that the most promising technologies in the table on page [53] — SOM and SEM, especially combined with array tomography — have relatively little discussion in the text that I can see. This makes me suspect that they’re only even superficially attractive because not enough is known about them to know they don’t work.

Also, given that the conclusion says ‘this sets a resolution requirement on the order of 5 nm at least in two directions,’ there’s far too much discussion of technologies that can only scan down to resolutions two orders of magnitude higher than this. So the text gives the optimistic prediction that ‘[KESM] enables the imaging of an entire macroscopic tissue volume such as a mouse brain in reasonable time’, but what good is that given that KSEM only scans down to 300nm x 500nm? It’s an obvious question, and I’d expect an honestly-written paper to answer it. Because this paper doesn’t, I smell a rat (or, more likely, someone clutching at straws).

The discussion starts ‘As this review shows, WBE on the neuronal/synaptic level requires relatively modest increases in microscopy resolution…’ which may be technically true but vastly understates the difficulty of increasing the resolution of the techniques discussed.

Again, though, I’ll defer to someone who’s done this stuff more recently than I have (and in a medical area — I was mostly looking at metal-matrix composites rather than anything organic).

This stands out from the field in that it is actually in reply to something that someone who believes in cryonics has actually said; it only doesn’t meet the criteria that I asked for in my open letter in that it is blog comment rather than an article, but knowing how busy David is it’s hard to imagine him finding the time to rewrite it in article form any time soon, so with his permission I’m posting it as is.

Updated 2010-02-20: Liam Proven steps up to the plate and meets three of my four criteria. Thanks Liam!

I’ve received lots of interesting comments on my recent posts about cryonics, for which many thanks. However, what I’m really hoping to provoke is something more: actual blog posts and other articles. In this regard, though I think it has many shortcomings, I’m grateful for the work that David Gerard has put into the RationalWiki article on cryonics.

This may seem like an arbitrary distinction; both are forms of writing that can help come to an informed decision, and ignoring someone’s writing on the sole grounds that it’s in the form of a blog comment could be a big mistake. However, for these purposes there are several advantages to articles/blog posts that make them much more useful for this project.

First, articles are meant to stand alone. A blog comment has an implicit context and assumes that the reader is familiar with it. Where an article needs context, it explains and links to the context as needed. This makes it easier to link to and more useful to the recipient.

Second, more work generally goes into articles. Every one of the posts to this blog, even the one that just lists statements from the Society for Cryobiology, has had more work put into it than all but a tiny fraction of my blog comments. That’s all work that’s meant to make the reading experience smoother and the argument clearer and easier.

Thirdly, more pride goes into articles. This is closely related and a little vaguer, but at least speaking for myself I’m often happy to dash off a blog post voicing my best guess at an opinion on something based on only the briefest understanding of the subject area. But an article in general will have a larger readership, and is I think more representative of what I think; much more care will go into trying to say only what I’m prepared to try and defend.

If all you’re trying to do is convince me, you probably don’t need to worry about any of that, and indeed I’m grateful for the work you’ve done so far. But I’m hoping to encourage more than this: I want to bring into being what I was looking for when I started this mission, not only so that I can read it but so that future others in the same position can do likewise. And if you think, as many seem to, that I’m already too hopelessly lost to motivated cognition to be turned around on this issue, then it is them rather than me you should really have in mind when you think about applying finger to keyboard to address this issue. Your comments on blog posts like these may help them a little, but if you’re able to find the time to write them, articles and blog posts of your own will help a lot more.

Something different, to leaven out these cryonics posts.

Newcomb’s Paradox has been described as the most controversial dilemma in the history of decision theory. As told, it starts with Omega, a superintelligence from another galaxy. But yesterday it occurred to me to wonder: might a sufficiently skilled mentalist be able to do the same trick?

The mentalist selects a member of the audience in some way that reassures everyone that they’re not picking stooges. They come onto the stage and chat for a bit, then the mentalist brings out an opaque box and puts it on a perspex table. Next to it, they place a transparent box, in which a £10 note is clearly visible. And they say to the volunteer: “You can either have both boxes, or just take the opaque box, but you have to decide now, before you open either. ”

“The snag is, I’ve guessed what you’re going to do. If I think you’ll take just the opaque box, you’ll find £100 in it when you open it. But if I think you’ll take both boxes, then you’ll find the opaque box empty. Now choose: will you take one box, or both boxes?”

At which point the audience member announces their intent, and is invited to open the opaque box. And to their mild astonishment, the audience see that the mentalist’s prediction has once again come true. Not being a mentalist, I don’t know whether this trick could really be done, but I’d love to find out.

Most people find the correct thing to do under these circumstances obvious. The trouble is, about half the people think it’s obvious you should two-box, because by the time you’re deciding, the opaque box is already either full or empty, so what you do can’t make any difference except to net you an extra tenner. And about half the people think it’s obvious you should one-box, because night after night the one-boxers walk away with £100 while the two-boxers walk away with £10.

Anyone know any good mentalists? Anyone good mates with Derren Brown?

The focus of this article is the technical plausibility of cryonics; though there are many non-technical objections, I’d like to treat the technical issue in depth before moving on to the non-technical.

Though many experts in cryogenics and other relevant fields are quoted in the media as condemning cryonics practice, none have written at greater length to explain their reasons. The closest thing to such a reason I can find is Michael Shermer’s article “Nano Nonsense and Cryonics”, but the reason he gave was one that he knew at the time of writing was contrary to scientific reality, and in response to my email asking where I could learn more he recommended three authors all of whom consider cryonics technically plausible. The only other anti-cryonics expert to respond to my email asking for more detail was John Bischof, but his replies didn’t carry the detail I was hoping for. (See my earlier blog posts A survey of anti-cryonics writing and More on anti-cryonics writing for details). Strikingly, even when the Society for Cryobiology passed their 1982 by-law barring cryonicists from membership, they produced no detail to back up their claim that “it is the Board’s scientific judgement that the prospects for re-animation of a frozen human, particularly a legally dead human, are infinitesimally low.” (see Society for Cryobiology statements on cryonics).

If cryonics really is nonsense dressed as science, this lack of detail is surprising, and in sharp contrast to pseudosciences such as homeopathy, on which volumes have been written pointing out its dodgy provenance, scientific implausibility and evidential defeat. It’s also very frustrating: I’m left trying to make a judgement call on a debate that only one side is participating in.

So this is my plea to the scientific critics of cryonics:

Please criticise cryonics.

If you thought that someone else had done it, if you thought that the article you’d want a cryonics hopeful to read had already been written, I hope that the surveys above show you that it really hasn’t. If it has, and I either haven’t found it or haven’t treated it fairly, I welcome your comments.

I’ve been trying to think about the reasons why someone like David Pegg would feel strongly enough about cryonics to take part in drafting that 1982 by-law using such strong language in his draft statements and his statements to the media on the subject, yet have nothing to say in reply to an email asking what he would recommend I read to see the other side of the argument. The only hint I currently have from critics is this remark in personal email from John Bischof:

I think the distinction is between a tissue being dead vs. alive at the time of freezing. I don’t believe there is anything I can possibly write that would further clarify that distinction.

But thinking about that remark, and other suggestions that friends have made on why they don’t see the need for such an article, I’ve thought of ten reasons an expert might give for its absence, and tried to answer them.

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This isn’t a cryonics blog, by the way, this is a blog for whatever subject of general interest I’m obsessing over this month; it’s just that at the moment, that’s cryonics.

From Scientific justification of cryonics practice (Ben Best, Rejuvenation Res. 2008 Apr;11(2):493-503):

Most neuroscientists agree that the anatomical basis of mind is encoded in physical structures of the brain, particularly neuropil connectivity and synaptic strengths [44] and possibly neuronal epigenetic structure [45].

[…]

[44] Abraham WC, Robins A. Memory retention—the synaptic stability versus plasticity dilemma. Trends Neurosci. 2005 Feb;28(2):73-8.

[45] Arshavsky YI. “The seven sins” of the Hebbian synapse: can the hypothesis of synaptic plasticity explain long-term memory consolidation Prog Neurobiol. 2006 Oct;80(3):99-113.

Here, I think “mind” refers to those features of mind that persist from hour to hour since it clearly doesn’t cover shorter-term features. I’d appreciate expert guidance on this point: how accurate is this claim?

(Wikipedia: Neuropil Chemical synapse Epigenetics)

I’ve managed to find out more about the Society for Cryobiology 1982 by-law barring cryonicists. This is just the documents; I may comment on them in a later post. Everything here comes from Alcor’s website; I didn’t find any other sources, but links of course welcome.

Section 2.04, Denial of Membership and Discipline of Members, reads in full as follows:

Upon a two-thirds vote of the Governors in office, the Board of Governors may refuse membership to applicants, or suspend or expel members (including both individual and institutional members), whose conduct is deemed detrimental to the Society, including applicants or members engaged in or who promote any practice or application which the Board of Governors deems incompatible with the ethical and scientific standards of the Society or as misrepresenting the science of cryobiology, including any practice or application of freezing deceased persons in the anticipation of their reanimation. Every member whose suspension or expulsion is under consideration shall be given written notice thereof at least fourteen (14) days before the vote on such suspension or expulsion, which notice shall state the grounds for the proposed action of the Board of Governors, and such member may petition the Board of Governors in writing before the vote.

sourceThis policy statement accompanies the by-law:

Society for Cryobiology

Policy Statement

The Society for Cryobiology has received inquiries regarding the policy of the Society toward the practice of freezing human cadavers in anticipation of eventual reanimation.

The Society recognizes and respects the well established freedom of individuals to hold and express their own opinions and to act, within lawful limits, according to their beliefs. Preferences regarding disposition of the dead are clearly a matter of personal choice and, therefore, inappropriate subjects of Society policy.

The Society does, however, take the position that cadaver freezing is not science. The knowledge necessary for the revival of whole mammals following freezing and for bringing the dead to life does not currently exist and can come only from conscientious and patient research in cryobiology, biology, chemistry, and medicine. The act of freezing a dead body and storing it indefinitely on the chance that some future generation may restore it to life is an act of faith, not science.

source Under threat of litigation from Mike Darwin, the final statement was considerably toned down; I include also earlier drafts that are at greater length.

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Further to my last blog post, A survey of anti-cryonics writing :

• I copied the article to LessWrong.com after being encouraged to do so by users there who also gave me some great help improving the writing. It had 215 comments last I looked.
• I received email from Ralph Merkle:

  I asked David Pegg to review an early copy of “The Technical Feasibility of Cryonics.” My exchange with him was published in Cryonics magazine in the July/August 1993 issue starting on page 22. I believe you will find it interesting.

  My response to Shermer’s story in Scientific American is on the web.

  And, of course, my thanks for your efforts to seek clarification from “critics” of their actual technical criticism (if any).

  I haven’t had trouble commenting, so any help anyone can provide reproducing and diagnosing these problems gratefully received.
• I missed a couple of anti-cryonics articles in my survey:
  • João Pedro de Magalhães, Cryobiology and Cryonics. Repeats the “ice crystals” error.
  • Corpsicles in The New Yorker. Written too late for me to include. Similar criticisms apply; see Ben Best in the comments.
• I found this article in which John Bischof speaks out against cryonics, so I mailed him, and he very politely replied almost immediately to say that cryobiologists consider cryonics a “faith based approach”, and pointed me at the Society for Cryobiology home page. Pressed for more detail, he replied:

  I think the distinction is between a tissue being dead vs. alive at the time of freezing. I don’t believe there is anything I can possibly write that would further clarify that distinction.

  I’ve yet to reply to this email; I may write a more general open letter to cryonics critics and send him a link. As always, I’m grateful for the time taken to reply.
• Updated 2010-02-16: I found this Detroit News article in which Society for Cryobiology President John K Critser voices a negative opinion. Email sent 2010-02-11, no reply so far.
• Updated 2010-02-20: Have now emailed again everyone I emailed last time drawing their attention to these articles. Really hoping that some of what I’ve written here spurs one of them into writing a more detailed attack on some aspect of cryonics.
• Updated 2010-02-20: Got a reply from Stephen Barrett MD of QuackWatch: “Sorry, I am not interested in further involvement in your project. ”

For its advocates, cryonics offers almost eternal life. To its critics, cryonics is pseudoscience; the idea that we could freeze someone today in such a way that future technology might be able to re-animate them is nothing more than wishful thinking on the desire to avoid death. Many who battle nonsense dressed as science have spoken out against it: see for example Nano Nonsense and Cryonics, a 2001 article by celebrated skeptic Michael Shermer; or check the Skeptic’s Dictionary or Quackwatch entries on the subject, or for more detail read the essay Cryonics–A futile desire for everlasting life by “Invisible Flan”.

That it seems so makes me sad, because to my naive eyes it seems like it might work and I would quite like to live forever, but I know that I don’t know enough to judge. The celebrated Nobel prize winning physicist Richard Feynman tells a story of a US general who spoke to him at a party and explained that one big challenge in desert warfare is keeping the tanks fuelled given the huge distances the fuel has to travel. What would really help, the general said, would be if boffins like Feynman could invent a sort of engine that was powered by sand. On this issue, I’m in the same position as the general; in the same way as a tank fuelled by sand seems plausible enough to him, it makes sense to me to imagine that however your brain stores information it probably has something to do with morphology and chemistry, so there’s a good chance it might not evaporate right away at the instant of legal death, and that freezing might be a way to keep the information there long enough for future societies to extract it with their future-technology scanning equipment.

And of course the pro-cryonics people have written reams and reams of material such as Ben Best’s Scientific Justification of Cryonics Practice on why they think this is exactly as plausible as I might think, and going into tremendous technical detail setting out arguments for its plausibility and addressing particular difficulties. It’s almost enough to make you want to sign up on the spot.

Except, of course, that plenty of totally unscientific ideas are backed by reams of scientific-sounding documents good enough to fool non-experts like me. Backed by the deep pockets of the oil industry, global warming denialism has produced thousands of convincing-sounding arguments against the scientific consensus on CO2 and AGW. Thankfully in that instance we have blogs like Tim Lambert’s Deltoid, RealClimate, and many others tracking the various ways that the denialists mislead, whether through cherry-picking evidence, misleading quotes from climate scientists, or outright lies. Their hard work means that denialists can barely move or speak without someone out there checking what they have to say against science’s best understanding and pointing out the misrepresentations and discrepancies. So before I pony up my £25 a month to sign up to cryonics life insurance, I want to read the Deltoid of cryonics — the articles that take apart what cryonics advocates write about what they do and really go into the scientific detail on why it doesn’t hang together.

Here’s my report on what I’ve found so far.

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