Full Idea
As a result of the evidence of split-brains, it is possible that the ordinary, simple idea of a single person will come to seem quaint some day, …but we may be unable to abandon the idea, no matter what we discover.
Gist of Idea
We may be unable to abandon personal identity, even when split-brains have undermined it
Source
Thomas Nagel (Brain Bisection and Unity of Consciousness [1971], p.164)
Book Reference
Nagel,Thomas: 'Mortal Questions' [CUP 1981], p.164
A Reaction
I'm not sure what grounds you can have for a claim that we can't abandon our current view of selves, even when the new reality will be utterly different. Rather conservative? I would expect future concepts to roughly match future reality.