I think what underlies that 'obviously wrong' view in many cases is a recognition of the fact that in practice, we rely on continuity to establish identity.
A great many optical illusions and magic tricks depend on this: if entity A is here at T1 and entity B at T2, and I don't notice any T1/T2 discontinuity, I'm likely to behave as though the same entity had been here throughout.
Of course, generalizing from those intuitions to a more fundamental notion of some kind of epiphenomenal identity is unjustified, as you say.
Then again, claiming that what makes me who I am is functional activity or information content is problematic, also. It isn't clear, for example, that amnesia or brain damage makes me somebody else. Nor is it clear that if someone else is able to emulate me well enough to pass the equivalent of a Turing test, that developing that skill makes them me.
Mostly, I think is a composite notion, like . That is, we judge that identity is preserved by evaluating a close-enough match along many different axes, and there's no single property or set of properties that is both necessary and sufficient to establish identity.
I also don't think it matters very much.
Then again, claiming that what makes me who I am is functional activity or information content is problematic, also. It isn't clear, for example, that amnesia or brain damage makes me somebody else.
In case you thought I was implying that, let me clarify that the whole point is to deprecate binary oppositions such as "being someone else" vs "being the same person" and "still being oneself" vs "no longer existing".
So of course it's "not clear" that, say, frontal lobe damage leaves you the same person and i...
http://www.smbc-comics.com/index.php?db=comics&id=2186
Convincing argument, or faulty metaphor?
I would go with the latter, but I don't trust my brain's abilities at 5:30 in the morning.