According to alethic functionalism, truth is a generic alethic property related to lower level alethic properties through the manifestation relation. The manifestation relation is reflexive; thus, a proposition’s truth-manifesting property may be a lower level property or truth itself, depending on the subject matter properties of the proposition. A true proposition whose truth-manifesting property is truth itself, rather than a lower level alethic property, is plainly true. Alethic functionalism relies on plain truth to account for the truth of propositions with (...) challenging subject matter properties, such as logically complex propositions and truth attributions. In this paper, it is argued that plain truth leads to a number of serious problems for alethic functionalism. First: Shapiro argues that plain truth threatens alethic functionalism with collapse to strong alethic monism; it is argued here that collapse is not merely threatened, but that, on pain of contradiction, collapse is immediate. Second, alethic functionalism’s commitment to alethic pluralism requires lower level alethic properties to be ways of being truth, where one property’s being a way of being the other property is irreflexive; thus, alethic functionalism is incoherent due to the conflicting commitments to a manifestation relation which is both reflexive and irreflexive. Third, it is argued that a reflexive manifestation relation leads to the contradiction that a lower level alethic property which manifests truth is both identical to and distinct from truth itself. Fourth, careful examination of the notion of a core truism shows that Objectivity and the correspondence intuition are the only core truisms. Finally, it is argued that the first and fourth problems jointly entail a collapse of alethic functionalism to strong correspondence monism. (shrink)