 The “passive perception” model can also be termed the “classic” model in that it claims to offer a more literal reading of Dharmakīrti. This model, adopted for instance by Sakya Pandita, takes “non-belying,” combined with “novelty,” as definiens of reliable cognition. Without giving a pragmatic view of reliability, this model involves the capacity to fulfill a goal, or to have some causal efficacy, as a criterion for the non-belying character of cognition. Although being non-belying and novel is sufficient to qualify as reliable, in a transactional context, conventional reliable cognitions are expected to lead to an ascertainment (nges pa). While inference ascertains its object by itself, perception is unable to do so, because ascertainment—a conceptual operation, equivalent to the elimination of opposite superimpositions—is incompatible with its being “devoid of conceptualization.” Such an ascertainment, should it occur (this requires a number of circumstantial elements), must be performed by a conceptual cognition that follows perception. In other words, perception is reliable in itself, but has to rely on a subsequent conceptual mental episode for ascertainment. This “two-tier” way of accounting for both reliability and determination keeps a strict division as to the role and capacity of non-conceptual and conceptual cognitions, which Sakya Pandita compares respectively by way of illustration to “a seeing mute” and “a speaking blind.” Should a subsequent ascertainment not arise immediately (due to the nature of the object, competence and mindfulness of the cognizer, visibility, etc.), the preceding episode of perception still qualifies a a reliable cognition, but its reliability has to be ascertained extrinsically.