Chapter 74: Saturation: Why 3
the relevant chapter proved the Saturation Theorem (III.T03) abstractly: the enrichment functor F_E applied to E₃ yields E₃ again, so E₄ = E₃. Since then, Parts II–IX have filled every enrichment level with concrete content. This chapter revisits saturation with that content in hand, testing the abstract collapse against proof theory, ZFC, and Book III itself. In every case, the next enrichment step produces nothing new. Section 5 states the Applied Saturation Theorem (III.T49) and the Terminal Level Characterization (III.P31). Section 6 draws the philosophical consequence.