I actually am signed up for cryonics.
My issue with the basic tech is that liquid nitrogen, while a cheap storage method, is too cold to avoid fracturing. Experience with imaging systems leads me to believe that fractures will interfere with reconstructions of the brain's geometry, and cryoprotectants obviously destroy chemical information.
Now, it seems likely to me that at some point in the future the fracturing problem can be solved, or at least mitigated, by intermediate temperature storing and careful cooling processes, but that won't fix the bodies frozen today. So I don't doubt that (barring large neuroscience related, unquantifiable uncertainty) cryonics may improve to the point where the tech is likely to work (or be supplanted by plastination methods,etc), it is not there now, and what matters for people frozen today is the state of cryonics today.
Saying there are no fundamental scientific barriers to the tech working is not the same thing as saying the hard work of engineering has been done and the tech currently works.
Edit: I also have a weak prior that the chemical information in the brain is important, but it is weak.
Just to be a cryo advocate here for a moment, if the information of interest is distributed rather than localized, like in a hologram (or any other Fourier-type storage), there is a chance that one can be recovered as a reasonable facsimile of the frozen person, with maybe some hazy memories (corresponding to the lowered resolution of a partial hologram). I'd still rather be revived but having trouble remembering someone's face or how to drive a car, or how to solve the Schrodinger equation, than not to be revived at all. Even some drastic personality changes would probably be acceptable, given the alternative.
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