Comment on MIT Technology Review - Michael Hendricks opinion on Cryonics

Thu, 17 Sep 2015 14:44:13 GMT

Straw man. Connectonomics is relevant to trying to explain the concept of uploading to the lay-man. Few cryonics proponents actually believe it's all you need to know to reconstruct the brain.

I don't think so, Cryonics is predicated upon the hypothesis that the fine structural details which probably can't be preserved with current methods are not important to reconstruct personal identity.

The fact that someone can be dead for several hours and then be resuscitated, or have their brain substantially heated or cooled without dying

I don't think that substantial heating is survivable. Where did you get that information?

Anyway, the type of disruptions that occur to brain tissue during cryopreservation (hours-long warm ischemia, cryoprotectant damage and ice crystal formation and thermal shearing) are very different than those which occur in all known survivable events. Warm ischemia can be reduced with prompt cryopreservation (but even in the highly publicized case of Kim Suozzi, where death was expected and a lot of preparation took place, they still couldn't avoid it), it's unclear how much ice crystal formation can be reduced (it's believed to also depend on cryopreservation promptness, but that's more speculative) and cryoprotectant damage and thermal shearing are currently unavoidable.

This is not, to the best of my knowledge, true, and he offers no evidence for this claim. Cryonics does a very good job of preserving a lot of features of brain tissue.

You are reversing the burden of evidence. It's the cryonics supporters that have to provide evidence that cryonics preserves relevant brain tissue features. To my knowledge, this evidence seems to be scarce or absent. AFAIK, no cryopreserved human brain, or a brain of comparable size, was ever analyzed. There were some studies done by ALCOR on dog brains, but these were never replicated by independent researchers. Dog brains, anyway, are smaller and hence easier to vitrify than human brains.

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