Is the CMB Frame a Modern Ether? Lorentz Invariance and Temporal Foliation in Chronon Field Theory

Many readers of Chronon Field Theory: Unification of Gravity and Gauge Interactions via Temporal Flow Dynamics (Li, 2025) raised concerns regarding the theory's introduction of a preferred temporal foliation—known as the Real Now—and its implications for Lorentz invariance. This monograph was written in direct response to those questions. We provide a detailed clarification of how the Chronon field Φμ(x)\Phi^\mu(x)Φμ(x), which defines the causal structure and simultaneity hypersurfaces of spacetime, leads to a dynamically selected, cosmologically coherent foliation without violating the core principles of relativistic field theory. In particular, we show that Chronon Field Theory (CFT) preserves Lorentz invariance at the level of the action and field equations, with all frame selection emerging spontaneously in specific vacuum solutions. The empirical alignment of the Real Now with the CMB frame is shown to result from causal relaxation in the early universe, not from any imposed absolute structure. We also derive quantitative predictions for potential Lorentz-violating observables—such as sidereal variations in atomic clock frequencies and high-energy scattering asymmetries—demonstrating that such effects remain suppressed below current experimental limits. This work positions CFT as a UV-consistent and testable framework in which temporal flow becomes a fundamental dynamical field, reconciling causal order with relativistic symmetry. This document is a companion to the main CFT paper [DOI: 10.5281/zenodo.15340460] and is intended to serve both as a clarification for researchers and as a formal appendix for future publication.