While I want to generally direct people  to this post on the shifting abortion debate—though I hope you’re all reading Democracy in America anyway—it strikes me that there’s a potentially handy distinction there that I feel sure someone else has made, but I haven’t come across previously, so forgive me if I’m reinventing jargon. When we call an argument or a view pluralist, it seems like we can mean one of two things.  What I want to call an “externally pluralist” argument goes like this: Given that reasonable people hold profoundly different worldviews, and given that the disagreement is unlikely to go away anytime soon as long as there’s some modicum of freedom of thought, prefer a policy that is, to the greatest extent possible, neutral between these. In the context of education, for instance, an external pluralist is likely to think that public schools should perhaps steer clear of contentious topics such as religion, or perhaps better still, that school choice programs should be implemented to avoid the need to agree on a common curriculum. An “internal pluralist” approach is one that tries to show how the same position can attract support from many different worldviews. We might think here of the “safe, legal and rare” position on abortion, which starts from the premise that abortions will in fact happen anyway, so even if one regards them as wrongful killing, it’s better that they be safer—and perhaps, as a result, more likely to happen earlier on in gestation. (As I’ve made clear, of course, I’m not sold on that approach myself, though I see the appeal.)

I went with “external” in the first sort of case here because I’m imagining us looking down at a diverse group of citizens just taking as a datum the fact that they disagree, without being overly concerned with the details of what each of them thinks.  The motive for external pluralism can be partly practical: If we didn’t have church-state separation, the stakes of politics would become much higher for some people, and we’d see even more destabilizing struggle for the rains of power. But it can also follow from higher-order principles. A-la Mill, we might be fallibilists who think that when intelligent and reasonable people disagree so deeply, everyone ought to be cautious about enforcing their own view. Even if we’re pretty sure our neighbors are wrong, we might think neutrality is a way of signalling our respect for their equal dignity.

With “internal” pluralism I’m imagining us, first, actually getting “inside” the diverse views people hold to see what these different perspective might entail, and second, importing these diverse justifications into our argument for the pluralist policy. Of course, the points on which genuinely diverse worldviews all tend to converge on the same practical result are also unlikely to require much in the way of consciously pluralist justification: They’ll just be the things that everybody agrees about. In practice, people will want to construct internal pluralist arguments when you’ve got a collection of worldviews that support radically different first-best policies, but maybe less obviously overlap (perhaps for different reasons) on a second- or third-best policy. One interesting consequence here is that it may sometimes be a virtue that the arguments offered on behalf of a policy are inconsistent. It’s common enough in argument to hear an objection that runs like this: “Justification A and Justification B rest on conflicting premises, so you can’t have it both ways—which is it?” In some of those cases, a good answer might be that if conflicting premises all lead us to the same conclusion, so much the better that we don’t have to choose between them.

Often internal and external pluralist considerations will have the same upshot. The external pluralist argument for church-state separation should be obvious. The internal pluralist argument can start with the observation that for any proposed state religion, many people will oppose it on the grounds that it is the wrong religion. But the candidate state religion may also itself have doctrines that eschew entanglement with worldly power, that warn against ostentatious display of religiosity, or that hold only truly uncoerced religious observance as pleasing to God.  But this need not be the case. For one, it ought to be fairly clear that internal pluralism is much more contingent on the specific mix of views in the population. An external pluralist argument is one that goes across just on the premise that people have persistent and deep disagreements; you don’t know what kind of internal pluralist argument will work until you know a good deal more about what the particular sources of disagreement are. The flip side of this is that an internal pluralist approach will potentially yield much “thicker” solutions compatible with one or another particular mixes of worldview. So it may turn out in any case that there’s acutally a plurality of pluralist approaches to a question.

The next question is whether there’s any general or systematic reason to think the internal and external pluralist approaches are likely to overlap often. I’ve got a handful of other proto-thoughts on this, but I want to go back and reread John Tomasi’s Liberalism Beyond Justice and Hirschman’s Exit Voice and Loyalty before I wade in any further.