This chapter offers the second of three hypotheses in this volume. It argues that under specific conditions, not only can a film title serve as a Documentary definiens (as was the case with Chap. 11 on Greaves), but also that the title of an academic article can serve as a valid Documentary definiens. Ergo, I constitute the “Article-title=Documentary-definiens (A-t=D-d)” hypothesis. In 1987, Plantinga became the first academic in the period 1960–1990 to explicitly and actively propose an article title that prompts the exploration of the action of “Defining Documentary” as a dual analytical action that conditions and secures its future discourse. First, in a more general sense, the act of “Defining Documentary” constitutes a necessary, though still insufficient, philosophical action in its own right. Second, it is a sign of the need to establish a clear and unambiguous delineation of the question “What is Documentary?”—that is, to provide sufficient reasoning for the foundations upon which any forthcoming documentarological inquiry will be set on its true rather than false course. The chapter studies Plantinga’s arguments and language games concerning the primordial function of defining Documentary, shining light on the historical context of his predecessors, on the shoulders of whom he made his assertive stance.