Could Not Have Noticed Four Modes of Cognitive Inaccessibility and the Ambiguity of Perceptual Blame

After a missed finding on a chest radiograph, a reviewer says: she should have seen it. The judgement presupposes that she could have. I argue that “could have seen it” is systematically four-way ambiguous, and that posterior-level predictive-processing explanations do not by themselves distinguish the relevant possibilities because a posterior is defined over a content space whose construction, acquisition, and finite-time exploration are not themselves posterior quantities. I distinguish four modes in which a content z may fail to become cognitively effective: architectural exclusion, where no setting of the system’s learnable parameters yields z; acquisitional exclusion, where some setting would yield z but the current one does not; dynamical inaccessibility, where z is instantiable under current parameters but fails to become accessible with effective probability within the operative horizon; and inferential suppression, where z is accessible in time but predictively disfavoured. The modes are nested but individuated by what is held fixed across distinct timescales, and their truthmakers are respectively combinatorial, acquisitional, transport-theoretic, and inferential. The typology adapts the approximation–optimization–estimation decomposition from statistical learning theory, adding a synchronic/diachronic split within the estimation term and a structural diagnostic of finite-time transport based on the spectral properties of a metastable-state generator. I then show how the four readings of “you could have noticed” redirect responsibility toward different loci—credentialing, training, workload design, and the individual clinician—and argue that expert assessors are systematically prone to misclassify the first three modes as the fourth. The framework therefore yields both a mechanistically explicit analysis of perceptual responsibility and a testable structural source of hindsight bias distinct from its familiar memorial form.