I don’t think this is a good illustration, at least for me, since I would never stop caring about someone as long as it was clear that they were biologically human, and not brain dead.
I think a better illustration would be this: take your historical ancestors one by one. If you go back far enough in time, one of them will be a fish, which we would at least not care about in any human way. But in that way I agree with what you said about values. We will care less and less in a gradual way as we go back—there will not be any boundary where we suddenly stop caring.
I don’t think this is a good illustration, at least for me, since I would never stop caring about someone as long as it was clear that they were biologically human, and not brain dead.
I think a better illustration would be this: take your historical ancestors one by one. If you go back far enough in time, one of them will be a fish, which we would at least not care about in any human way. But in that way I agree with what you said about values. We will care less and less in a gradual way as we go back—there will not be any boundary where we suddenly stop caring.