My last post asked whether PRL is superfluous and trivial, or instead question-begging. But it had us imagine that, say, utilitarians had kick ass argument for X.
In reality, though, most of the time, the arguments we have for this policy or that aren't all that great. Should we have lockdowns? Should we force people to wear masks? Should we make people pay for public schools administered by the government? Should we force citizens to fight in WWII?
In these cases, the evidence on either side is far from overwhelming, the people on either side producing the evidence are ideologically motivated and flawed, the people making arguments are often dishonest or self-interested, people in three of the cases are acting out of fear and on short notice, and so on. That's not to say all sides are equal, but to say that reasonable people could have serious doubts. So what should we do?
The public reason liberal proposes that in a situation like this, we can impose coercive policies only if we meet their internal standards, whatever those are. But, then again, so do the deontological libertarian, perfectionist liberal, communitarian, deontological Marxist, theocrat, fascist, and utilitarian. Each of them say that when we have reasonable public disputes about what to do, we may nevertheless do certain things and must forbear from doing others, where what determines this is...the internal standards of their particular theory. Public reason liberalism is just another parochial theory with its own parochial views about how to handle disagreement. It's nothing special.
Is this an impasse? No. Rather, it depends on what theory, if any, is actually correct. It depends on what justice actually requires. If the correct theory of justice is PRL, then we have to deal with reasonable disagreement they way they say, whatever that is. But if PRL is not the correct theory of justice, then their standards don't matter because they are false. They cannot point to the problem of reasonable disagreement as evidence of the truth of PRL; rather, how to deal with this problem and what the moral significance of the problem is depends on what the correct underlying theory is.