[foldr]

>what is _really_ true IS what makes the best predictions. Otherwise in what sense is it true?

That is the anti-realist position, but it could be true in the sense that it corresponds to the actual nature of reality, if you are a realist.

> You have only one data point: your own consciousness.

Yep, and that is the data point that physicalism doesn't seem to be able to account for.

[nazgulnarsil]

you're covering it up with the term "actual" what does that mean?

your second assertion doesn't make any sense either. "account" would imply that pzombies would be different from "normal" normal people I guess?

[foldr]

No, you could delete "actual" and it would still convey the right sense.

Yes, p-zombies are different from normal people (by definition).