brain damage also raises awkward questions about selfhood and consciousness and free will, like if you find yourself asking “did she do that on purpose or did her brain make her do it?” when the answer is just “yes.”
if there’s been an abrupt change in behaviour due to an injury then you can at least model “what she would have wanted” and hopefully guide them back to that, but in a situation of gradual change even that’s unclear.
either way, the idea of a “true” self that we might be sadly disconnected from due to physical damage is nothing but a comforting illusion; we are what we are, and sometimes what we are changes.
You could apply this to any sort of mind altering substances as well, like alcohol, drugs, or even anesthetics. In an altered state, are you still your self? I think there’s interesting philosophical discussions to be had surrounding the effect of these on identity and self, but nobody seems to be having them.
Like, if you only learn to play a instrument while blackout drunk, such that your sober self has no memory of practicing, do you still retain the skills developed during that time? If yes, wouldn’t that be pretty crazy to discover that you know how to play the guitar?
given that task memory and declarative memory are different, it’s entirely possible for someone with amnesia to learn a new skill without forming any memories of the lessons, that’s pretty wild.
in the other hand I have no memory of not being able to read, either.
As someone who has, separately, decades apart, had amnesia and then some nerve trauma that changed his personality, they’re kind of opposites, one erases your narrative self but leaves your instinctive self and the other one is reverse