Tensor Field Dynamics (TFD) describes gravitation, inertia, and light propagation as manifestations of a deterministic scalar tension field φ. In contrast to quantum field theory, vacuum energy is not interpreted as a physically effective energy density but as a mathematical artifact arising from the absence of a causal field reference.Using a finite-range Yukawa-type field equation and a field-dependent light law c(ϕ)c(\phi)c(ϕ), TFD provides a self-consistent description of cosmological observations without free parameters. The well-known discrepancy of roughly 123 orders of magnitude between theoretical and observed vacuum energy density disappears entirely, as vacuum energy has no physical meaning within the TFD framework.TFD thus replaces the vacuum energy problem with a causal field-mechanical description yielding testable predictions.