You lose whatever information is no longer in the atoms, which might be a lot because the skull is not designed to assist cooling, and the brain is a considerable thermal mass. It’s going to cool slowly, be shredded to mush by crystal formation, and be warped and cracked by thermal stress, while undergoing runaway chemical reactions and cell death. Your “limit of perfect technology” is then faced with an awe inspiring task of running the reaction products backwards, modelling and reversing the thermal damage, un-killing the cells, and splicing the cracks, in 3D on tissue that does not come with alignment hints, and then inferring a mind. There’s going to be some level of physically unavoidable data loss even in the perfect case, the data is entailed in thermal noise and random photons and the damage is no longer reversible without reversing the universe. Presumably the perfect technology will paper over these cracks by copying in mind structures from Mr Perfectly Average. But the end result would be that you’re less you.
You lose whatever information is no longer in the atoms, which might be a lot because the skull is not designed to assist cooling, and the brain is a considerable thermal mass. It’s going to cool slowly, be shredded to mush by crystal formation, and be warped and cracked by thermal stress, while undergoing runaway chemical reactions and cell death. Your “limit of perfect technology” is then faced with an awe inspiring task of running the reaction products backwards, modelling and reversing the thermal damage, un-killing the cells, and splicing the cracks, in 3D on tissue that does not come with alignment hints, and then inferring a mind. There’s going to be some level of physically unavoidable data loss even in the perfect case, the data is entailed in thermal noise and random photons and the damage is no longer reversible without reversing the universe. Presumably the perfect technology will paper over these cracks by copying in mind structures from Mr Perfectly Average. But the end result would be that you’re less you.