Physically Constrained Replicator: And its Comparison with Existing Frameworks

We introduce the Physically Constrained Replicator (PCR), a newly proposedformal framework for characterising living systems, derived bottom-up from theminimal discriminating criteria between a living system and an inert physicalobject. Starting from replication, negentropy, and goal selection as primitivenecessities, and grounding each subsequent component — semiotics, many-to-manyinterpretation, nonlinear feedbacks, and the Von Neumann division — as logicalconsequences, we arrive at a necessity chain in which every component isload-bearing. We prove formally that RAF (Reflexively Autocatalytic andFood-generated) theory, the established framework for catalytic closure, isstrictly included in PCR (RAF ⊊ PCR), and show that the thermodynamically freelimit of PCR converges exactly on Von Neumann's universal constructor. Goalselection is grounded in Aubin's viability theory and Ashby's Law of RequisiteVariety as complementary formal foundations. PCR is the only framework in thecomparison capable of evolution, and the only one that is both logicallyself-referential and physically realisable.