 Further, the proponents of teleological theories rarely believe that referential content is a kind of narrow content, and so they are not usually offering theories of narrow content. How to characterize narrow content is controversial, but the proponents of teleological theories tend to agree with those who think that two beings who are physical replicas at a time t “from the skin in”, so to speak, can differ in the referential contents of their mental states at t. Of course, this view is also shared by plenty of other philosophers, who think that mental reference to content supervenes (in part) on things that are external to the individuals whose mental states are in question, such as on features of their social or physical environments and/or learning histories (perhaps for the reasons given by Putnam 1975 and Burge 1979, 1986). Still, a teleological theory of mental reference to content could be combined with the view that there is also a useful notion of narrow content. (See the entry on  narrow mental content.)