Leiter v. Shapiro on Theoretical Disagreement and Whether It is a Problem for Legal Positivism

My old friend Scott Shapiro (Yale) and I discuss this issue on "bloggingheads TV" here.  David Killoren (to whom our thanks for putting this together!) also provides links to the various papers that we reference during our discussion.  I learned a couple of interesting things about Scott's view that I had not appreciated previously, most notably that:  (1) he thinks that while some of the criteria of legal validity may, indeed, be fixed by a practice of convergent behavior (constituting a social rule etc.), he thinks the correct positivist respond to the problem of theoretical disagreement is to identify other social facts (unrelated to convergent behavior) that fix the criteria of legal validity in cases where what officials disagree about are those criteria; and (2) he thinks law does, indeed, have an "essential" function, namely, to try to make concrete what we, morally, ought to do (this comes up at the very end of the discussion).