This paper draws parallels between William James’ thought and Carl Gustav Jung’s work in Psychological Types, showing that both provided epistemologies that strived to redefine the notion of scientific objectivity to incorporate the realm of psychological experience. Jung generally admired James’ pragmatism and his pluralistic vision. He shared James’ idea that philosophical (and, therefore, epistemological) positions were ultimately expressions of certain psychological attitudes, which meant that a psychological typology could be used to account for the “personal equations” of philosophers, scientists, (...) and psychologists in particular. It will be shown that Jung borrowed from James the idea of a psychological typology as an epistemological method, which he believed would ensure a more complete understanding of scientific objectivity. Parallels will then be drawn between Jung’s notion of the “problem of opposites” and James’ concept of the “divided self,” both of which were resolved through religion. Crucially, for both Jung and James, expanding the borders of science to include psychology also meant incorporating religious experience. Finally, this paper argues that Jung’s epistemological project in Psychological Types effectively expanded on James’ pragmatism by synthesising various elements of James’s thought – pluralism, the personal equation, typology, and the divided self – into one epistemological framework. Jung’s work thus provides an important case study for the history of pragmatism. (shrink)