Synthetic Publicity: Common Knowledge and Heteronomous Bayesian Updating in Generative Information Environments

Generative systems can alter public belief without persuading each individual that a proposition is true. They can instead alter what individuals think other people believe, how independent those apparent beliefs are, and whether a signal appears publicly recognized. This conceptual paper introduces synthetic publicity: perceived public visibility or social corroboration unsupported by an equivalent population of independent human speakers, witnesses, or endorsers. It connects common-knowledge theory with Heteronomous Bayesian Updating, distinguishes the construct from repetition, social proof, astroturfing and strict common knowledge, and proposes falsifiable experiments. The paper reports no new behavioral data and makes no prevalence or causal-effect claim.