A lot of "cryonically-frozen" people are only their heads, since it's been well-known for a while that there's no way to unfreeze the bodies. I suspect it may literally be easier to scan their brains than to unfreeze them, even if they were healthier to begin with. That's not a statement of my belief in the ease of scanning a brain; it's a statement of my belief in just how hard it is to "thaw" a body and get anything back. I'd say it's like getting handed a pile of slag and told to turn it back into a working engine, except that task is multiple orders of magnitude easier.
But that's my point, why even bother freezing the brain, if simply waiting a few centuries more of tech progress will mean you don't even need the brain to be consciously brought back?
It's just replacing the faith in one omnipotent's afterlife with another.
How would that work? Future technology, no matter how advanced, would still require the information in your brain to simulate you. The point of cronics is to preserve that information.
But currently we don't know what "information in your brain" would be required, so it's a huge leap of faith to suppose that cryonics is successfully preserving it.
(That's supposing "information in your brain" would even be sufficient by itself. Another leap of faith.)
The connectome. Your identity is encoded in the neural network of your brain, which is preserved in vitrification. I don’t know why this is controversial.
That seems more to be an assumption you're bringing in, rather than others. There's a huge gulf between "technology that can read the structure of the brain and recreate it" (which seems to be something merely lacking in know-how and tech, but with no fundamentally-impossible steps), and "simulate the entire universe as-is, in situ, and assume it's 100% accurate, and pluck people out of it" (a la https://qntm.org/responsibility), which seems outright impossible as no system can simulate itself fully. I'm honestly having trouble wrapping my head around how you're both managing to insist on the latter being the only possibility while simultaneously telling people that it's a bad assumption.
But even the most advanced technology can’t accomplish magic. It still exists in the real world and is subject to physical law, such as the laws of statistical mechanics and information loss.
I don't think I'm splitting hairs. The quote, in context, is applied in the other direction: a sufficiently advanced technology which exists has mechanisms which seem indistinguishable from magic to a primitive mind. But you can't apply it in the other direction and say anything which seems like magic could exist with sufficiently advanced technology. This is because there are physical limits which constrain what any future technology could do.
To a pre-industrial mind, a cell phone would be magic. Other things that would seem like magic are faster than light travel, perpetual motion machines, or exact quantum state duplicators. However baring radically new and highly unlikely physics (which would be the hugest cop-out to assume), there will never ever be faster-than-light travel, perpetual motion machines, or quantum replicators. Such technology is simply impossible. Not "we don't know how to do it" but "we know that it cannot be done."
Likewise, once your brain is cremated or reduced to worm food, there is absolutely no way to recover that connectome information which defines who you are. The laws of physics disallow it.
I have only the slightest idea of what technology that is able to revive a cryo preserved brain would look like, and it would certainly seem like magic to someone today. But to revive a cremated brain would require actual magic. There's an important difference there.
If it were true then it means being you can be duplicated ad infinitum and therefore you have no personality on your own. I done think we have a good answer to that.
