Motif Geometry proposes that all of physics follows from a single foundational principle: every physical state is a section of a geometric bundle, and physical evolution minimizes a single energy functional. This Cause–Effect Axiom, together with a minimality condition on the choice of base manifold, uniquely selects ℂℙ² = SU(3)/U(2) from Cartan's classification of symmetric spaces. All physical fields — metric, gauge connection, fermion spinor — are components of a single map Φₑₓₜ into the tota