The fundamentality of relation over substance has been recognized across the history of human inquiry — from Heraclitus to Leibniz, from Faraday to relational quantum mechanics. Yet no formal framework has successfully operationalized relation as a primitive unit of analysis. Science has advanced under object-centric paradigms not because relation is less fundamental, but because no formalism existed to make it workable. We present Rational Field Theory (RFT), a minimal framework defined by a single expression: M(π) = { rij ∈ R | d(rij ) > 0 } where rij denotes a pairwise relation and d(rij ) its relational magnitude. No structural assumptions, no iterative optimization, no domain-specific parameters. Applied purely to the physicochemical relations among the 20 canonical amino acids, RFT yields relational clusters consistent with established biological facts without any structural input — hydrophobic (I–L–M), charged (K–R), and polar (N–P –D–T ) groupings emerging from relation alone. Structure, where it exists, is its consequence.