One Spell to Model Them All: From Homo Oeconomicus to the General Equilibrium Universe

Physicists have spent a century chasing a Theory of Everything and have not caught it. Economists got there first. Starting from one stylized atom, the optimizing individual, they built a full cosmology of a competitive economy with a single tool: one constrained-optimization template, applied to consumers, then to firms, then lifted whole into an Arrow–Debreu equilibrium. This paper reconstructs that move as a spell: one optimization problem to model them all. We trace what mathematical and conceptual engineering each step demands, from the axioms of homo oeconomicus to the existence theorems that hold the edifice up. Rather than prove that the equilibrium exists, the paper computes it, and a companion dashboard puts every lever of the model in the students’ hands. The aim is to show students who already have the mathematics what the monument cost to build, so they can use it, and later drill holes in it.