  Frequent violations of fair principles in real-life settings raise the
fundamental question of whether such principles can guarantee the existence of
a self-enforcing equilibrium in a free economy. We show that elementary
principles of distributive justice guarantee that a pure-strategy Nash
equilibrium exists in a finite economy where agents freely (and
non-cooperatively) choose their inputs and derive utility from their pay. Chief
among these principles is that: 1) your pay should not depend on your name, and
2) a more productive agent should not earn less. When these principles are
violated, an equilibrium may not exist. Moreover, we uncover an intuitive
condition -- technological monotonicity -- that guarantees equilibrium
uniqueness and efficiency. We generalize our findings to economies with social
justice and inclusion, implemented in the form of progressive taxation and
redistribution, and guaranteeing a basic income to unproductive agents. Our
analysis uncovers a new class of strategic form games by incorporating
normative principles into non-cooperative game theory. Our results rely on no
particular assumptions, and our setup is entirely non-parametric. Illustrations
of the theory include applications to exchange economies, surplus distribution
in a firm, contagion and self-enforcing lockdown in a networked economy, and
bias in the academic peer-review system.
  Keywords: Market justice; Social justice; Inclusion; Ethics; Discrimination;
Self-enforcing contracts; Fairness in non-cooperative games; Pure strategy Nash
equilibrium; Efficiency.
  JEL Codes: C72, D30, D63, J71, J38
