Metaphors and, more broadly, metaphorical discourse, are widely recognized as not merely significant aspects of human language use, but also as both pervasive and essential elements of the communicative process as we understand it. Metaphors are important to understand for a variety of reasons, and their use and analysis has important implications for many disciplines. Nowhere, though, is this more true than in the case of semiotics. In this article, it is suggested that both historical and contemporary learning theories in general, and theories of language learning in particular, are in fact examples of metaphorical discourse. The case of constructivist epistemology will be examined in particular. The implications of the use of metaphor in such contexts will be explored, and suggestions will be offered for how educators might more carefully discuss and apply metaphorical models of learning. (Timothy Reagan)