Murphy on Mackie's Queerness Objection

An excerpt from Murphy's Natural Law and Practical Reason: 

The ontological worry about substantive theories of rationality is that the notion that there are independent reasons waiting to be grasped by agents is just too Platonically lush to endure.  In addition to our ordinary world of experience, there is an extra realm of things, reasons, which are quite unlike the usual things that we deal with.  But the real identity thesis along with the analogy to first- and third-person judgments on which it is based, suggests that this is but one, not terribly charitable, way to describe the situation presupposed by the defender of a substantive view of rationality.  When I say that it is straightforwardly true both that I am in my office and that Murphy is in his office, I am not committing myself to the existence of two worlds, the ordinary world, describable in a third-person way, and a peculiar, shadowy first-person world, in which there is a strange thing called 'I.'  Rather, there is but one world, which can be described in one way using indexical concepts and another using non indexical concepts.  When I say that it is straightforwardly true that there reasons for action, that certain states of affairs are goods, thing that make agents better off, this does not - if the real identity thesis is true - require me to say that there is another realm, in addition to the ordinary world with which we are acquainted; rather, I am speaking of a certain aspect of reality using normative rather than nonnormative, practical rather than theoretical, concepts.