Leiter on Garnett on Stone on Bush

Brian Leiter has weighed in on Geoffrey Stone's claim that President Bush's stem cell veto exhibited reckless disregard for the separation of church and state.  In addressing Rick's contribution to the debate, Prof. Leiter offers his perspective on "public reasons":

"Public reasons" are, by hypothesis here, reasons that may properly ground legislation and exercises of state power.  The argument that religious reasons are not "public reasons" isn't that they lack a certain kind of foundation that genuine "public reasons" have (perhaps this is what Professor Volokh was after with the talk about "provability"); the argument is that they aren't public, i.e., that they aren't the kinds of reasons acceptable to all reasonable people in a pluralistic society.  Many "public reasons" in this sense may lack foundations of one kind or another, but that has no bearing on their public status.  To put it (a bit too) crudely, reasons are "public" largely in virtue of a head count, not in virtue of their having more robust epistemic foundations.  So, contra Professor Garnett, it is not apparent that the the foundations of the beliefs or reasons in question are at issue here.

I have always thought that the distinction between public and non-public reasons centered precisely on epistemic foundations -- i.e. their epistemic accessibility -- partly because of the difficulty in reaching any semblance of consensus in identifying the sort of reasons that would be "acceptable to all reasonable people in a pluralistic society."  For those who have thought more deeply about this than I ever will (hello Michael P.?), are public reasons commonly defined via the head count method?  And can identifying the reasons acceptable to all reasonable people occur without addressing, at some point, the epistemic foundations of those reasons?

Rob