The virtual objects of the argument are composed ("coded") from "first principles" which such principles implicitly assume the desired conclusion. This is the perfect shadow of a real argument, in that if this process is not abused, we ought to consider the arguments on its merits. We are never required to accept the arguments, or any part of them, as factual, but are critical of them until their utility is properly demonstrated.
The context of the argument is a virtual world in which the events of the rhetorical drama take place, and is declared to be representative in all the necessary ways to our own world, and this and all subsumed points are simply held to be self-evident and inarguable. Any divergence in representation is further represented to be a strength, rather than a weakness, of the included arguments.
"The will of Father Jim," (Ex Niliho) "in Jonestown, Guyana." (In Vacuo)
Thanks to "The Political Hat" The Veil of John Rawls’ Ignorance for an excellent discussion of the arguments of John Rawls.