The cosmological constant problem is the largest numerical discrepancy in physics: quantum field theory estimates of vacuum energy exceed the observed value by up to 120 orders of magnitude. This paper argues that the discrepancy is a category error, and that the observed constant is the direct energy density signature of a single physical substrate filling space.
One measured density reproduces the observed value with no fine-tuning and no additional fields. The derivation, the numerical comparison, and the falsifiable consequences are laid out step by step.