The Prince, the Rose and the Sunday Contradiction - Rethinking Sleeping Beauty

The Sleeping Beauty problem (SBP) is traditionally framed as an insoluble conflict between the “Halfer” (1/2) and “Thirder” (1/3) positions. This paper demonstrates that the 1/3 position is logically untenable by introducing the “Sunday Argument.” Through a reformulation that isolates the physical event (a Prince and a Rose), we prove that applying Thirder logic leads to a systemic calibration contradiction. Crucially, this argument does not rely on the Reflection Principle nor is it vulnerable to objections based on amnesia. We introduce the topological distinction between an epistemic “Filter” and an observational “Echo,” arguing that if a rational agent anticipates a priori that their updating rule will systematically force them to overestimate an immutable physical event without any possible worlds being eliminated, the agent is not updating information via evidence; they are succumbing to a self-induced sampling bias.