In the newish Public Reason blog, Robert Talisse writes:
I’ve been working on Berlin-style value pluralism lately. I’m particularly concerned with the attempt (made by Galston and Crowder, among others) to derive liberal political commitments from value pluralism. My sense is that value pluralism has no entailments regarding politics. But that’s a topic for another day.
Nope. It's a topic for today! My sense is that every value theory has no entailments regarding politics. Whatever value it is you're after, it's an empirical question what institutional arrangement will produce it. Which is why political philosophers are useless in that Kantian “concepts without experience are empty” sort of way without a bit of social science. Liberal neutrality is a practical way of dealing with the fact of moral disagreement — with the fact of pluralism in moral conceptions. You don't need the deeper truth of value pluralism to generate the fact of pluralism. But actual value pluralism, if true, would help explain why observed pluralism is deep — people are out there responding to all these different actual values and prioritizing them in different ways — which would tend to reinforce the need to accommodate diversity in moral conceptions, which would tend to support liberal toleration and liberal state neutrality. That's not an entailment. One does not derive it. But given the historical fact that liberalism has been a fairly practically successful way of dealing with the fact of religious and moral diversity, its pretty easy to understand how metaethical value pluralism might be thought to point toward liberalism. Right?