  A second possible worry about Shafer-Landau’s strategy is that it does rely on a metaphysics which quantifies over tropes (Shafer-Landau prefers to speak of ‘property instantiations’ but this is really a merely nominal difference).  This is itself a controversial metaphysical commitment.  Moreover, Shafer-Landau seems committed to meta-tropes—tropes of tropes.  For he needs this thesis to explain how a fact (which for Shafer-Landau just is a property instantiation) can itself have the property of being a reason.  While this is of course a metaphysical commitment that can perhaps be defended, it does give some dialectical hostages to fortune.