Cultural Evolution Operates on Two Tiers: Mind and Social Ratification

Tyler Volk draws a critical distinction that much interdisciplinary discourse overlooks: the word "evolution" covers fundamentally different kinds of processes, and treating them as interchangeable generates deep conceptual confusion. Drawing on Donald Campbell's framework, Volk identifies a specific evolutionary structure defined by propagation, variation, and selective retention (PVS). This PVS dynamic is not a metaphor stretched across domains — it is a recurrent mechanism that manifests at distinct scales: prebiotic chemistry, Darwinian biological evolution, operant learning in animals, and human cultural systems.

What makes Volk's analysis especially productive is his claim that cultural evolution operates as a dual-tier PVS. The first tier is a mental PVS: individuals generate internal variations — ideas, hypotheses, imagined possibilities — and subject them to cognitive selection. The second tier is a group PVS, in which social agreement systems function as collective selective retention mechanisms, determining which ideas propagate through communities and which are discarded. Culture stabilizes not through either process alone but through their coupling.

This architecture maps with striking precision onto Greg Henriques's Justification systems framework, which similarly distinguishes between internal mental Justification (the private filtering of beliefs) and social Justification (the public legitimation process). The convergence suggests a robust structural insight: cultural forms emerge through individual cognitive variation but persist only through social ratification. Any account of cultural evolution that attends to only one tier — treating culture as purely individual cognition or purely social dynamics — will systematically misidentify the mechanisms driving cultural transformation and stability.