Maintaining perfect biological health (including for the brain) is a more objective target than maintaining an abstract person implemented by the brain, there is more philosophical difficulty in defining what success means. A healthy brain in a million years might just effectively end up containing someone else, in a way that its original inhabitant wouldn’t endorse on reflection. And there might be insufficient time for that reflection to occur in a single lifetime while the original person is still there and didn’t yet become someone else. AGI-written textbooks on the topic might help, but avoiding undue influence via such textbooks is similarly harder to define than autonomy in thinking on your own.
Maintaining perfect biological health (including for the brain) is a more objective target than maintaining an abstract person implemented by the brain, there is more philosophical difficulty in defining what success means. A healthy brain in a million years might just effectively end up containing someone else, in a way that its original inhabitant wouldn’t endorse on reflection. And there might be insufficient time for that reflection to occur in a single lifetime while the original person is still there and didn’t yet become someone else. AGI-written textbooks on the topic might help, but avoiding undue influence via such textbooks is similarly harder to define than autonomy in thinking on your own.