Human Function: The Body's Capacity for Normal Task-Bounded Calling

This paper proposes a conceptual framework for defining human function as the body's capacity for normal task-bounded calling. It argues that human function should not be reduced to diagnosis, movement names, techniques, scores, or local findings. Instead, human function is understood through the way real tasks and contexts call upon the body to organize, mobilize, coordinate, sustain, and regulate its capacities. The paper develops the concept of task-bounded calling and explains how human function can be understood through task demands, required calling, actual bodily calling, observed state expressions, cost, boundary, functional state, priority problems, and decision loops. It further distinguishes calling mode from functional state, and state expression from functional state, in order to avoid reducing human function to symptoms, movement faults, or isolated test results. The purpose of this paper is to provide a conceptual foundation for human function judgment across medicine, rehabilitation, training, manual therapy, health management, and long-term functional service. It does not replace medical diagnosis, clinical treatment, rehabilitation assessment, or professional decision-making. Rather, it offers a common conceptual starting point for understanding how the body is called upon in real life and how functional judgment can move from state understanding to decision loops.