In this thesis, I first present Fred Dretske's theory of mental represent- ations, which purports to show how a physical thing could have (non-derived) meaning. In order to illustrate the applicability of the theory to an actual physical system, I discuss the theory in relation to two theories of audio localization (i.e., the capacity to locate the source of sounds in one's environment). Having clarified the theory, I examine two charges laid against it. Lynne Rudder Baker charges the theory with circularity. Her charge is refuted by appealing to the concept of a "standby function." Stephen Stich charges the theory with vagueness. His charge is refuted by appealing to a general analysis of functions. I conclude that a careful use and analysis of the previously unanalyzed term "function" makes possible the refutation of these two charges.