| Structural semantics is a theory that purports to explain how mental states come to represent or "be about" external objects and states of affairs. According to this view, both mental states and the things they represent can be described as sets of elements structured by relations. It is in this sense that mental states and external states of affairs are what we call "relational systems." A mental state, or "cognitive relational system" represents some external state of affairs, or "external relational system," when and only when there is a homomorphic function mapping the elements of the cognitive relational system to those of the external relational system.;Because the only necessary condition for representation is the existence of a homomorphism between the representation and thing represented, structural semantics may be criticized for failing to specify adequately which of any number of external relational systems a given representation is about. In other words, insofar as representations will always map homomorphically to more than one external relational system, structural semantics cannot support the assignment of representations to unique objects or states of affairs in the external world. This is referred to as "the uniqueness problem" for structural semantics.;This dissertation examines various ways of raising the uniqueness problem for structural semantics including a version of the problem expressed through Quine's arguments regarding translational indeterminacy and a persistent version of the problem introduced by Quine in Ontological Relativity and Other Essay.1 In addition to providing an exposition of the "mechanics" of structural semantics as a theory of mental representation and to formulating a response to the uniqueness problem, this dissertation attempts to evaluate the ability of structural semantics to satisfy a number of basic conditions commonly thought to be required for any adequate theory of mental representation.;1Quine, W. V. O. Ontological Relativity, and Other Essays. New York: Columbia University Press, 1969. |
