I haven’t read that one, will check it out. If we take his “Permutation City”, I think the character Peer is quite unrelatable, and only then because they give some human background. A story consisting only of creatures hacking their own reward functions makes motivations more alien than “not quite like ours” IMO.

I assume post-humans will be smarter and unlock new forms of cognition. For example BCI to connect directly to the Internet or other brains seems plausible. So in the same way that a blind person cannot relate to a sighted person on visual art, or an IQ 75 person is unlikely to be able to relate to an IQ 150 person on the elegance of some complex mathematical theorem, I assume there will be equivalent barriers.

But I think the first point around motivation hacking is the crux for me. I would assume post-humans will fundamentally change their desires (indeed I believe that conditional on there being far more technologically advanced post-humans, they almost certainly _must_ have removed much of the ape-mind, lest it force them into conflict with existential stakes.)