Off the bat, my specific question is actually if someone can point me to the philosophic domain of inquiry which deals with the above question.
In context, I am doing a paper on Rawls. Joseph Raz says that Rawls's conception of Justice as Fairness does not adhere to the epistemic abstinence that it claims.
Patrick Neal counters that "Rawls is in the position of one who has chosen to play, say, baseball and is confronted with the charge that in doing so he has in effect committed himself to the view that, as athletic games go, baseball is superior to, say, football. There is a piece of evidence supporting the charge; he is, after all, plying baseball... but in so choosing Rawls is claiming neither that baseball is superior for all purposes to football nor that this purpose [hand-eye coordination involved with baseball] is superior to any other.
I think Neal misses the point. Me choosing to play baseball is trivial and does not contain a normative implication. But, if I choose to eat vegan, that is of a fundamentally different category. In doing so I am also rejecting non-veganism. Rawls's Justice as Fairness (or any other political theory, necessarily) seems to be in the same camp as veganism. That is, it seems to be of a different order. Any theory of justice implies a rejection of not-that-theory-of-justice. My question is what philosophic inquiry deals with why this seems to be the case (or perhaps why it doesn't).