Why c² in E = mc²? A Mechanistic and Computational Model of Physical Reality

This paper reframes the question: Why does c² appear in E = mc², and what does this imply about the physical foundations of energy and mass? The Computed Universe (CU) model interprets mass as information density and energy as the total causal compute required to preserve that information over time. In this framework, c² emerges naturally from the geometry of light-speed-limited causal surfaces, which scale in two dimensions across spacetime. This leads to a mechanistic derivation of E = mc² and unifies relativistic and quantum phenomena under a finite, surface-based computational model of reality.