The past several decades bear witness to the emergence of a cause that has become tremendously, even wildly popular in contemporary scholarship. The cause in question is pluralism. We use the term “cause” rather than “concept” for two reasons. First, pluralism itself is a set of concepts; among our tasks is to explore the extent to which the varying concepts cohere, and in what ways. Second, we say “cause” because our focus is principally pluralism in psychology, within which pluralism is frequently encouraged or endorsed rather than merely analyzed in a distanced way on a conceptual level. We find that since the 1990s there have been many references to pluralism in psychology and explicit calls for psychology to embrace a pluralistic framework for reasons that are sometimes cast as moral in nature, suggestive of a cause and, perhaps, a therapy for the discipline (e.g., Goertzen & Smythe, 2010; Kirschner, 2006; Slife & Wendt, 2009; Teo, 2010a; Ussher, 1999; Viney, 2004; Wertz, 2011). As we will make evident in Chapter 2, promotion of pluralism or a pluralistic approach to psychology comes in many forms and appears in an array of diverse contexts.