The study of reference often leads to addressing fundamental issues in semantics, metaphysics and epistemology; this suggests that reference is closely linked to the three realms. The overall purpose of this study is to elucidate the structure of some of these links, through a close examination of the “mechanism” of reference. As in many other enquiries, considering the possible (i.e., the modal,) in addition to the actual proves very helpful in clarifying and explicating insights. The reference of a term with (...) respect to possible worlds is commonly called “intension”; so this is a study of intensions. The main contribution of the study is an outline for a “calculator” of intensions. It is argued that the intension of a term is a function of three variables: (a) the way in which the term “picks out” its referent in different possible worlds (semantics); (b) criteria of identity (metaphysics); and (c) the actual state of affairs (actuality). While considering different possible values for these variables, it is demonstrated how the variables combine to generate the term’s intension. In other words, the result is a calculator that when provided with the required values, yields the reference of the term in different possible worlds. By taking into account the possible gap between what we take the values of these variables to be and what they may in fact be, we also gain important insights into the epistemic aspect of reference. In addition, since a rigid designator is a term with constant intension, the proposed thesis provides an elaborate account of rigidity. The first chapter is devoted to the development of the calculator of intensions. Each of the following three chapters elaborates on one aspect of intensions, namely, the semantic, metaphysical and epistemic aspects. In the course of these chapters, various familiar puzzles pertaining to the respective philosophical realms are addressed (many of these puzzles are discussed in Kripke’s Naming and Necessity – a work that considerably inspired this study). In the fifth and last chapter the analysis of intensions is applied to two case-studies from relatively recent philosophical literature: the Kripke-Lewis debate over the identity theory of mind, and the debate over the significance of Donnellan’s referential/attributive distinction. The novel accounts that these applications generate purport to illustrate the importance and originality of the proposed thesis. (shrink)