Geometric Economics: Heuristic Bounded Rationality, the Bond Geodesic, and the Death of Homo Economicus

Classical economics rests on Homo economicus---the perfectly rational agent who maximizes a scalar utility function over all possible actions. This model is mathematically elegant and empirically false. Behavioral economics, following Kahneman and Tversky, has documented systematic deviations from rational choice but lacks a unified mathematical framework that explains these deviations occur and they share. We provide that framework. We show that economic decision-making is not scalar optimization but ---a weighted simplicial complex whose dimensions include not only monetary cost but moral constraint, social norm, cultural taboo, reputational risk, and temporal discounting. The agent's decision is modeled as A^* search with evaluation function f(n) = g(n) + h(n), where g(n) is the accumulated economic cost (System 2: slow, deliberate calculation) and h(n) is the (System 1: fast, automatic boundary enforcement). We call the resulting optimal path the . The framework yields five principal results: (1) The : moral and cultural heuristics are not ``biases'' but admissible search heuristics that reduce an intractable optimization to a tractable one, at the cost of provably bounded suboptimality. (2) The : projecting the multi-dimensional decision manifold to scalar utility destroys information that is mathematically irrecoverable---``irrational'' behavior is rational on the full manifold, irrational only on the projection. (3) The : the replacement for Nash equilibrium when agents optimize on the full manifold rather than on the scalar projection. (4) : Kahneman and Tversky's loss aversion, reference dependence, and probability weighting emerge as geometric properties of the decision manifold's metric. (5) The : in closed economic exchanges, the total moral friction is conserved---unfairness in one dimension must be compensated in another. The framework unifies classical economics, behavioral economics, and moral psychology into a single geometric structure. Homo economicus is not wrong because humans are irrational; it is wrong because it computes on the wrong manifold. Author preprint deposited for archival and citation. Draft — pending author review.