diagnostic

Diagnostic operates through abductive inference: it infers the best explanation from incomplete observations. Remove abductive inference (reasoning from observations to hypotheses) and diagnostic practice ceases to function — it has no reasoning mechanism. The edge-test confirms abductive-inference is older/more-foundational (epoch 0.01, foundational mode of reasoning predates formalized diagnostic practice). Present-tense removal test: no abductive reasoning → no diagnosis.

Diagnostic practice operates by classifying symptoms/signs into diagnostic categories. Removal test (Law 8): remove classification and diagnostic loses its categorization mechanism — it cannot assign findings to disease/condition types. The note pins the constitutive sense: diagnostic's core operation IS classification-based reasoning, not incidental association.

Diagnostic IS a specific kind of problem-solving: it identifies, classifies, and diagnoses issues within a system. Law 9: a competent speaker would call diagnostic practice 'a problem-solving.' Direction correct (specific→general).

A health check is a specific kind of diagnostic: a systematic assessment procedure to determine the current state or condition of a system, component, or process. A competent speaker would call a health check a type of diagnostic activity.

Cepstrum is designed and maintained for the sake of diagnostic applications. In practice, cepstral analysis extracts features from vibration signals to detect bearing faults, gear defects, and machinery anomalies — the quefrency-domain representation separates convolution components, enabling diagnostic feature extraction that frequency-domain methods cannot achieve. Its designed purpose in industrial applications is to further diagnostic operations.