Spacetime Rigidity and the Emergence of Dark Energy (v2)

Dark energy and the cosmological constant can be interpreted as emergent effects of spacetime discreteness at the Planck scale. A reduction of effective degrees of freedom, enforced by Planck limits, the Heisenberg uncertainty principle, and holographic entropy bounds, introduces an intrinsic rigidity of spacetime. This rigidity stores residual energy, manifesting macroscopically as a vacuum-like contribution driving cosmic acceleration. Quantitatively, a suppression of degrees of freedom by a factor of order 10⁻¹²³ naturally yields the observed value of the cosmological constant. The framework bridges quantum mechanics, relativity, and cosmology, offering a structural interpretation of Λ. This is Version 2, which harmonizes the presentation with forthcoming companion papers and includes extended appendices on falsifiability and historical-philosophical context.