Viruses as Living Systems? Borrowed Closure and the Limits of Autopoiesis

In 2022, a metacybernetic account argued that viruses are alive by moving the criterion for life from metabolism to organisation, treating the genome–capsid couple as autopoietic. This study reframes that conclusion with two constructs of Fisher-Generative Informational Realism (FGIR). The first distinguishes the boundary between a Complex Adaptive System (CAS) and a self-sustaining Complex Adaptive Autopoietic System (CAAS). The second embraces the coercivity law, which requires a system’s protoenergy, the informational effort needed to maintain a configuration, to exceed a threshold. Living systems can be argued to satisfy two conditions: a topological condition concerning the closure of their self-producing organisation and a resourcing condition concerning their capacity to supply the protoenergy needed to sustain that organisation. The idea that viruses are not autopoietic conflates these two conditions, since viruses satisfy the topological condition but fail the resourcing condition. The host, rather than the virus, holds the capacity to maintain the viral self-producing network, a condition termed borrowed closure. Identifying the viral protoenergy with the draw on the host, and letting self-supply return only when the lineage’s translation machinery is complete, yields a host-budget equation with a saddle-node bifurcation at a critical completion fraction. Given a near-all-or-nothing return, the barrier is structural rather than statistical, surviving stochastic and epidemiological reformulations and persisting under delay as an oscillatory failure. Its value, however, is schematic, lying between about 0.06 and 0.6 under the two regeneration forms. The account is falsifiable and taxonomically agnostic, as Carsonella ruddii shows, and the boundary is crossed only downward.