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I'm a biomedical scientist with expertise in preservation and storage of neural tissue. Have you considered that maybe it is you who is wrong and not the scientists? Look scientists can and have been wrong. It's a tradition in science! And maybe us scientists are wrong in this case, again, wouldn't be the first time! But I have not seen compelling evidence. The one actual peer-reviewed study you linked was just combining fixation with cryopreservation, nothing particularly interesting or novel. It preserves the microstructure pretty well, as one would expect. But there is no evidence that preserving a snapshot of the structure of a dying brain will actually be able to be recreated in any capacity. When sceptics of cryonics call it pseudoscience, this is what they mean. Where is the evidence for this?

I mean really it all comes down to this question: How can the dynamic system of the brain can be recreated from a static image of a dying brain? I mean let's assume that the best current techniques perfectly preserve the brain at some state. And let's assume that this was done while the individual was still alive, so it's a live brain at the time of fixation. This is a best case scenario. How does one take this static image of the brain and use it to recreate the actual dynamic system?

It's like trying to recreate an entire 2 hour video from a single frame, except, ya know, many MANY orders of magnitude more complex and with preservation techniques that are definitely imperfect (at least a still frame from a video can be easily preserved 1:1 from the source material).

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Hi, thanks for detailed feedback. :)

"there is no evidence that preserving a snapshot of the structure of a dying brain will actually be able to be recreated in any capacity."

Not knowing the evidence doesn't mean that it doesn't exist!

Careful cryonicists generally make something along the lines of the conjunction of two claims,

1. Current techniques, or techniques that we could feasibly develop, preserve a fair amount of information critical for long-term memory, and specifically, what is associated with personal identity, in neural tissue.

2. It is technically feasible to extract this information from neural tissue, constituting some form of revival. Revival here should not be taken to mean anything narrow; indeed, even if we are not able to restore anyone to full health, extracting memories from neural tissue may still provide enormous value.

For evidence of the first point, I provided a source that argued, using the standard scientific literature, that Aldehyde-stabilized cryopreservation can preserve an organism's long-term memory. Specifically, I cited https://nectome.com/the-case-for-glutaraldehyde-structural-encoding-and-preservation-of-long-term-memories/.

(Apologies for not being peer reviewed. The arguments contained are still worth reading!)

The evidence for point two can be viewed as simply the natural conclusion of our current paradigm of computational neuroscience. Computational neuroscientists build dynamic models of the brain, given information about the brain's function. If computational neuroscientists did not believe it were possible to extract information from brains well enough to model them, their entire field would be rather pointless.

The heart of your objection seems to be that we cannot extract enough information from a brain at a single point in time in order to reconstruct the function of the brain across time. I don't quite understand why you'd say that, however. Given a sufficiently well-specified physical model of a brain, a set of initial conditions should perfectly well allow us to compute the state configuration of the brain at any future point in time. Would you agree?

The reason why we cannot reconstruct a 2 hour video from a single frame is because a single frame does not encode enough information about the video requisite for its reconstruction. Simply put, a video is not a dynamical system in a physical sense (unlike the brain). A more complete physical model of the video would involve things like, the actual physical video production process, including editing and its actors etc.

If you simply think that current techniques do not store an adequate amount of information for any useful information extraction, then I encourage you to explain exactly why and how you came to that conclusion.

I want to point out that I'm not beholden to any particular current technique or practice. When the field of rocketry was in its infancy, the fact that we had not sent objects to space did not automatically imply that the field was pseudoscience. Similarly, that we have not yet revived people who had their brains cryopreserved does not imply that cryonics is pseudoscience. These things happen slowly.

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Go to Google Scholar and enter "cryonics". Read the articles.

Even a casual review will reveal that the articles generally support the feasibility of cryonics, and there are no articles that present even a vaguely credible technical argument against cryonics.

As for your claim that the information necessary to successfully revive a human brain cryopreserved using "the best current techniques" "while the individual was still alive" is missing is clearly wrong. If we know the complete and exact structure of the human brain, there is no known impediment under existing physical law to restoring it to a fully functional state.

If you argue that the technology required to carry out such restoration is not currently available, then your argument is reduced to the claim that anything which has not been done can never be done at any time in the future: a clearly incorrect claim. If you argue that fundamental physical law prevents us from constructing a physical object which has been fully specified, then I refer you to Feynman's "There's Plenty of Room at the Bottom". Feynman understood back in 1959 that the ability to arrange atoms the way we want would necessarily be developed at some point in the future.

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Does it bother you at all that this particular line of reasoning would fit 1:1 on a site like NaturalNews if you replaced "Cryonics" with... basically any alternative medicine treatment?

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I'm not sure what you mean by "this particular line of reasoning." Do you believe that the scientific mainstream is always right? In any case, this wasn't a full argument for my position. If you want one, I'd point you towards other sources, which would do a much better job than me. See https://www.brainpreservation.org/content-2/overcoming-objections/

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For a more scientific focused article focused on the current feasibility of brain preservation, I'd read https://nectome.com/the-case-for-glutaraldehyde-structural-encoding-and-preservation-of-long-term-memories/

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Well done on the introduction, but you forgot to post the actual piece.

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I didn't care to argue for the position. This post is more for people who understand where I'm coming from. I'll add a line at the bottom pointing people to more fully fleshed out arguments.

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I think that's a vedetta by some biased Wikipedia editors. Wikipedia has quite a lot of biased articles these days - and the cryonics article is one of them.

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