Stress-Testing the Retentive Infrared Hypothesis: Failure Modes, Degeneracies, and Falsification Boundaries in ISW Physics

This paper presents an adversarial stress-test of the Retentive Infrared (IR) Hypothesis proposed within retentional cosmology. Rather than extending or promoting the model, the article is explicitly structured as a falsification audit. The analysis systematically probes failure modes, parameter degeneracies, null-model confusions, and observational traps that could either invalidate or falsely support the hypothesis in Integrated Sachs–Wolfe (ISW) physics and low-frequency cosmological observables. The paper introduces explicit kill zones—regions of parameter space where the hypothesis provably collapses—and subjects the model to: • joint inference under ΛCDM backgrounds, • cosmic variance testing, • kernel sensitivity analysis, • null-model elimination, and • prior robustness checks. No signal reported in this work is treated as evidence. The sole function of the paper is to establish where the hypothesis becomes non-identifiable, redundant, or unphysical. The outcome is intentionally binary in scientific terms: either the hypothesis survives hostile validation, or it invites revision through further refinement and clarification. This document is part of a larger research sequence in retentional cosmology, forming the falsification component complementing the theoretical and observational papers released in parallel.