Peer review The Atacama Cosmology Telescope - DR6 Constraints on Extended Cosmological Models Blake Sherwin Cambridge

This document presents a formal referee report on the manuscript “The Atacama Cosmology Telescope: DR6 Constraints on Extended Cosmological Models” (arXiv:2503.14454).The review demonstrates, using explicit mathematical criteria, that the models analyzed in the manuscript do not constitute physical theories but phenomenological parameter extensions of an assumed baseline dynamics. It is shown that the absence of a closed generative principle, the reliance on freely introduced parameters, and the existence of a trivial null limit prevent these extensions from testing foundational assumptions of cosmology. The report distinguishes rigorously between statistical inference and theoretical explanation and argues that likelihood-based consistency cannot be interpreted as physical validation in the absence of structural necessity. On these grounds, the manuscript is evaluated as conceptually misleading, and rejection is recommended.