Teleosemantics and productivity

There has been much discussion of so-called teleosemantic approaches to the naturalization of content. Such discussion, though, has been largely confined to simple, innate mental states with contents such as There is a fly here. Even assuming we can solve the issues that crop up at this stage, an account of the content of human mental states will not get too far without an account of productivity: the ability to entertain indefinitely many thoughts. The best-known teleosemantic theory, Millikan's biosemantics, offers an account of productivity in thought. This paper raises a basic worry about this account: that the use of mapping functions in the theory is unacceptable from a naturalistic point of view.