The set of simulation possibilities can be subdivided into PHS (posthuman historical), AHS (alien historical), and AFS (alien future) simulations (as posthuman future simulation is inconsistent).

What these categories meant was not clear to me on first reading.

I currently understand AFS as something like aliens finding earlier [humanity[ and trying to predict what we will do. AHS would be the result of Aliens interacting with a more mature humanity and trying to deduce particulars about our origin, perhaps for use in an AFS.

If I have that right, PFS might not be entirely inconsistent, as one posthuman might try to fully model another, at least into the near future. Edit: oh but WE are not those simulations. (unless there is a secret government foomed AI modeling a future in which it remains secret, and it's really 1985)