No science today, I’m afraid, but I did want to point anyone who’s behind on their back issues of The New Yorker toward a nice piece on cryonics (on the movement in general and the Cryonics Institute in particular).

I mention this here because while scholars of biogerontology don’t generally study cryonics, the latter subject seems to orbit the former like a dim moon. I tend to get questions about cryonics when I make public appearances to talk about longevity research. That isn’t surprising, since both subjects share a common goal, if not methodology or standards for intellectual rigor. Consequently, my ears tend to prick up whenever I see it mentioned in the mainstream popular literature.

I’m a cryonics skeptic of the “extraordinary claims require extraordinary evidence” flavor. As I’ve said before, I suspect that long-term preservation of the potential for life by freezing or other means is physically possible, but at present I don’t think we’re making any significant progress in that direction. Part of the problem is that there’s very little serious initiative within the mainstream of academia or industry to build the many, many necessary precursor technologies. Another part is that the problem is really, really hard – harder than the comparatively simple but still unsolved problem of maintaining cellular viability within tissues at low temperatures. In the New Yorker article, they hit the nail on the head:

“Neuropreservation” has a scientific attitude, but that doesn’t make it science. Credentialled laboratory scientists don’t generally think the dead will one day awaken. The consensus appears to be that when you try to defrost a frozen corpse you get mush. And even if, in the future, scientists could repair the damage done to cells by freezing and thawing, what they would have, at best, is a cadaver.

Got that? In order for cryonics to work, we have to be able to do a lot of hard things:

  1. Preserve cells at ~100% viability.99% just ain’t gonna cut it, especially in tissues like the heart and brain, and we’re barely there even in ideal situations like loose cells in rich media loaded with antifreeze compounds
  2. Cure the disease or other condition that (would have) killed the subject. I’ve never been clear on whether that would happen in the frozen state, or the inanimate and presumably further deteriorating thawed corpse. Both pose formidable technical hurdles.
  3. Bring people back from the dead. Literally resurrect them.

That last step is, as they say, a doozy: Let’s imagine that you’ve got a dead person on the table: their cells are viable, you cured whatever ailed them – but not only are their brain and heart silent, but the metabolism of every cell is at best restarting from an inactive state, and I suspect that your handy defibrillator is not going to do the job. Cryonics advocates tend to elide the distinction between “thawed” and “revived”.

Granted, our definition of “dead” has changed a lot over the past century. Once upon a time, you were dead if your heart stopped – now we routinely bring people in cardiac arrest “back from the dead” in that sense. Now we define death by reference to brain activity, but I suspect even those definitions are already in flux.

Still, I would submit that someone who has died or ended their own life; frozen or otherwise preserved their bodies; been subjected to radical molecular or cellular processing sufficient to reverse a lethal illness, along with any damage incidental to the preservation procedure; and thawed themselves out (either before or after the aforementioned processing), is – by any definition we can imagine at present – really really quite very dead. It behooves any would-be cryonaut to give this issue serious thought in any evaluation of one’s chances for revival.

Lest if I sound closed-minded, allow me to reiterate my ultimate position: Extraordinary claims require extraordinary evidence. In the face of such evidence, I’ll gleefully change my view. In other words, show me the (figurative) money. I’m waiting for someone to take the tools of modern biology and take a few steps in the right direction: The viable freezing, preservation, and thawing of (at first) individual tissues, then organ systems, and (eventually) an intact small mammal. Start with skin! If we can’t do skin, we can’t do a whole body, so we might as well start small (and thin). Skin sounds downright easy.

The field could take a lesson from the dawn of modern biogerontology back in the early 1990s: Acknowledge the mind-bending complexity of the challenge. Create model systems for cryonics, using the best tools from the vast edifice of modern biological knowledge. Break down the problem into feasible steps. And then, by all means, full steam ahead.