Within the philosophy of mind, consciousness is currently understood as the expression of one or other cognitive modality, either intentionality (representation per se), transparency (immediacy of cognitive content consequent upon the unawareness of underlying representational processes), subjectivity (first-person perspective) or reflexivity (autonoetic awareness). However, neither intentionality, subjectivity nor transparency adequately distinguishes conscious from nonconscious cognition. Consequently, the only genuine index or defining characteristic of consciousness is reflexivity, the capacity for autonoetic or self-referring, self-monitoring awareness. But the identification of reflexivity as the principal index of consciousness raises a major challenge in relation to the cognitive mechanism responsible for operationalizing such a reflexive state. Current reliance by higher-order and intrinsic self-representational theories on self-representing data structures to achieve reflexive self-awareness is highly problematic, suggesting a solution in terms of a self-referential processing regime.