[davidm]

It seems evident to me that what links Old Paul and New Paul is the physical brain and body.

We may say, under some ideas of personhood, that Old Paul and New Paul are two different persons. But it's plain that their different "personhoods" supervene on the same brain and body.

Yes, the "pattern of thoughts" is obliterated at the moment of brain injury. There is an unfelt time gap, agreed. And then New Paul emerges. But New Paul remains supervenient on the same physical body and brain, no?

I agree that Old Paul "passes" to New Paul, but we understand this in terms of an objective physical link: brain (though rearranged) and body.