When I've brought up cryonics on LessWrong [1][2], most commenters have said I'm being too pessimistic. When I brought it up yesterday at the Cambridge MA meetup, most people thought I was too optimistic. (I think it could work, but there are enough things that could go wrong that it's ~1000:1 against.) What makes the groups so different on this?
And also, among other things, software outside your brain (including in other brains). My brain might be the main part of my identity, but not its only part: other parts of it are in the rest of my body, in other people's brain, in my wardrobe, in my laptop's hard disk, in Facebook's server, in my university's database, in my wallet, etc. etc. etc.
Many of those things cryonics couldn't preserve.