A Thermodynamic Foundation for General Relativity Gravity as Entropy Field Modulation of Causal Structure

This paper presents a complete thermodynamic derivation of general relativistic phenomenology from a scalar entropy density field. The coupling constant κ = 4π G²kBT ln 2/c⁵ is derived from the Landauer principle, ℏ establishing the identity κs (r) = GM/r between the entropy field potential and the Newtonian gravitational potential. From this identity, all seven classical tests of general relativity are reproduced: time dilation, light deflection, Shapiro delay, perihelion precession, gravitational wave speed, gravitational wave frequency, and Einstein ring formation. The Hawking temperature and Bekenstein-Hawking entropy are recovered, and the holographic principle is derived as a consequence of entropy density reaching a critical processing threshold at the event horizon. The framework survives the Hulse-Taylor binary pulsar test and is consistent with all current observations. Three distinctive predictions are identified for next-generation instruments: Yukawa gravitational screening at cosmological scales, gravitational wave polarisation content including a possible scalar breathing mode, and the presence or absence of event horizon echoes. The ontological claim is precise: spacetime is flat; the entropy density field modulates the rate of causal event processing, producing observational predictions equivalent to curved spacetime. DISCLAIMER Generative AI was used to assist with literature screening / coding support / draft language revision. All AI-assisted outputs were independently checked by the author, and the author takes full responsibility for the final analysis and text. This is encompassing all the work that has been done and will be done. All code is under MIT licensing. All research papers are under Creative Commons License. All code, outputs and notes are included in the reproducibility bundle zip file.