[davidm]

Originally Posted by wstewart

Essay reasoning is not as you suggest.

In this thread I've isolated the essay's preparatory scenario of Old and New Paul, with reason. E.g., it's easy to see that no 'germinal substance' is posited in that scenario.

What is posited?

And in your view, is anything more required, in order to justify the essay's conclusion that Old Paul passes to New?

I think most people would reply that Old Paul has "passed" to new Paul. The reason is that the substance of old Paul remains in New Paul, including the physical brain, shared by both Old and New. What has changed is the pattern of thoughts, the mentation, that supervenes on the physical brain. But since the substance of Old Paul continues in New Paul, albeit with a different pattern, it makes sense to posit a form of passage.

We could imagine an opposite state of affairs: that the pattern remains the same, but the substance on which the pattern supervenes is constantly changed or renewed. This is a Ship of Theseus scenario. What makes us tempted to conclude that it is the same ship, even though all its constituent parts have changed over time, is that the pattern that the parts exeplify remains the same.

So: We can imagine a pattern changing while supervening on the same underlying substance, as is the case with Old Paul and New Paul; or we can imagine the underlying substance changing, but the pattern it exemplifies remaining the same over time. Both cases tend to support the continuity of personal identity, or ship identity in the case of Theseus, over time.