  As I have argued elsewhere, it is not at all clear that the appeal to token constitution can do the needed work.  Moreover, even if this appeal could somehow explain supervenience, it would have further unfortunate consequences for the non-naturalist.  Since I have discussed these objections at length elsewhere (Ridge 2007), I shall be brief here and simply summarize the main worries.  First, Shafer-Landau’s constitution thesis by itself does not entail supervenience.  A full explanation of supervenience will require some auxiliary premises, and Shafer-Landau does not tell us what these premises are.  Fortunately, his appeal to an analogy with the philosophy of mind helps us fill in the blanks.  For the closest analogue there seems to be David Robb’s attempt to explain supervenience without reduction in the philosophy of mind in terms of tropes, where tropes just are property instantiations.  Trying to carry out the Robb strategy (which I shall not try to summarize here; for details, see Robb 1997), the needed premise for Shafer-Landau would seem to be that if a given natural trope constitutes a moral trope, then it necessarily constitutes that trope.  This, plus Shafer-Landau’s thesis that necessarily, every moral trope is fully constituted by some set of natural tropes, would indeed entail supervenience, so this does seem like an interesting way to fill out the details of his strategy.