“Our starting assumptions are probably right, ergo we can say with some confidence that the future will involve trillions of identical uploaded minds maximizing their utility functions, unless of course the Paperclip-Maximizer ‘clips’ it all in the bud”

I accepted the importance and correctness of their inference, but I ran it in the opposite direction:

“It seems obvious that we can’t say such things with any confidence, ergo the starting assumptions ought to be carefully revisited—even the ones about mind and computation that most scientifically-literate people say they agree with.”

I don't see how Scott's proposed revision of the starting assumptions actually changes the conclusions. Even if he is right that uploads and AIs with a "digital abstraction layer" can't be conscious, that's not going to stop a future involving trillions of uploads, or stop paperclip maximizers.