A Formal Framework for Human Function in UOHF

This preprint develops a formal framework for human function within the Unified Ontology of Human Function (UOHF). It retains the root definition: human function is the body’s capacity to be appropriately engaged to meet internal and external demands. The framework distinguishes human-function capacity from the engagement process through which that capacity operates, and distinguishes both from manifestations, measurements, inferred explanations, and information representations. It introduces a typed mathematical architecture comprising whole-person state, human-function capacity, internal and external demand, engagement-pattern specifications, realizability, ex ante appropriateness constraints, actual engagement processes, potential, predicted and observed responses, evidence status, limiting-factor hypotheses, governed actions, and longitudinal state update. The central demand-bounded realizability criterion specifies when a demand is appropriately meetable for a particular person, time, and context. The framework also separates problem hypotheses from evidence status, formalizes anatomical, physiological-process, observation, constraint and action anchors without treating an anchor as a causal diagnosis, and establishes a governed decision layer constrained by evidence, safety, professional authority, feasibility, stop conditions, reassessment and feedback. Illustrative stair-climbing knee-pain and internal-demand recovery cases demonstrate how the framework generates testable hypotheses and admissible next actions without converting manifestations into automatic diagnoses. This work is an implementation-oriented formal and research framework. It is not a completed whole-body equation, validated diagnostic algorithm, autonomous treatment system, clinical guideline, or already machine-executable ontology release. UOHF Definition 2.1 remains the current authoritative root definition of the framework.