Public reason liberals: What should we do?
Everyone else: The right thing!
Public reason liberals: And what is that?
Utilitarianism: What maximizes net utility!
Libertarians: Respect people's rights.
Perfectionist liberals: A liberal order that facilitates flourishing and virtue.
Conservatives: Defer to the authority of tradition and accept the third best because we can't do better.
Marxists: Murder all the rich people and take their stuff for ourselves.
Communitarians: Ensure we are all in community with one another.
Fascists: What that last dude said but I mean like really, really in community with one another.
Christian and Islamic fundamentalists: Instantiate the City of God.
Public reason liberals: Whoa! Whoa! Hold up! You see the problem here, right?
Everyone else: Yes, the rest of you are wrong about what's right.
Public reason liberals: So what should we do about that?
Everyone else: We should do what's in fact right. Obviously, the fact that some people dispute what rights and wrong is isn't a good reason not to do what's right or to do what's wrong. Morality doesn't work like that. It's not voluntarist.
Public reason liberals: But the problem is we all disagree.
Everyone else: Well, here are my arguments.
Public reason liberals: But we still disagree!
Everyone else: Ok, why don't you tell us your view. We know you're itching to do so.
Public reason liberals: Great, finally. Thanks. OK, so here's the problem. You're all offering first-order reasons for substantive theories of justice and whatnot. But what we need to do is find a way to work and live together without violence when we disagree. We can't have no norms at all--chaos! But we can't just ram our views down other's throats. At the very least, they'll fight back. But, further, isn't it part of respecting people to justify yourself to them?
Everyone else: Well, we did justify ourselves--we gave arguments. Here they are again, in case you missed them.
Utilitarians: What it means to respect people is to maximize utility!
Libertarians: No, it's to respect their rights.
Christian and Islamic Fundamentalists: No, it's to treat them as children and servants of God.
Public reason liberals: Never mind that. What I think we should do is instead ask what we could all agree to if we accepted that we can't convince others our views are correct, but we still want to live and work together. So, why don't we start by assuming that everyone is free and equal and that all coercion has to be justified according to the following sets of standards which everyone committed to a fair and reasonable society could be...
Utilitarians: Hey, wait, hold on! You're not solving the problem any more than I am. All you're doing is saying that when people disagree, we should accept your substantive theory of justice. You're saying we should assume a bunch of controversial stuff about people's status, about which reasons count and which don't, about coercion vs freedom, and so on. You sound like the deontological liberal, the libertarian, and the perfectionist liberal. The only difference is that they say their view is correct and you say your view is special kind of compromise given that we can't convince each other...but then you basically say we should compromise by assuming a bunch of stuff you like and not stuff you dislike.
Fascists: Yeah, why don't we just instead assume that we should do whatever is right, according to the true standard of ethics, whatever that is?
Deontological liberals: Yeah, what the fascists said.
Communitarians: Seriously, public reason liberals, it's like you just said, "Everyone, since we disagree, I suggest that we compromise or resolve our disagreements by instead agreeing to my own personal substantive theory."
Public reason liberals: But it's not a first-order substantive theory! I'm not saying it's true!
Everyone else: We agree with you that your theory isn't true.