Roger David Spencer

We propose that life is best understood as the manifestation of biological agency—the capacity of a system to initiate, regulate, and sustain its own organization across molecular, organismal, and ecological scales. This activity is viability-oriented: living systems maintain and reestablish the conditions required for their persistence. The agency–process–scale (APS) framework provides a naturalized, operational account of this organization through six biosignatures of agency: homeostasis, adaptive plasticity, selective boundary regulation, goal-directed behavior, recursive self-repair, and cross-scale coordination. These biosignatures describe what living systems do rather than what they are made of, and are empirically tractable across biological, synthetic, and astrobiological contexts. Unlike nonliving self-organizing systems, living systems actively regenerate the constraints that sustain their organization, producing an intrinsic asymmetry between conditions that support persistence and those that undermine it. Framing life in terms of viability-oriented organization clarifies ambiguous cases such as viruses and protocells, recasts evolutionary transitions as reorganizations of agential structure, and grounds biological purposiveness in ongoing activity rather than design or representation. APS does not offer a final definition of life, but a minimal, testable framework for investigating the organization that makes living systems possible. By foregrounding agency while clarifying its organizational basis, APS integrates functional, processual, and scale-sensitive perspectives into a coherent account of life’s distinctive dynamics.