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formal · 1801 to 1877
In 1838 a French mathematician worked out how two rival firms choose output when each depends on the other, and quietly wrote down the first Nash equilibrium, 112 years before Nash.
Facts reviewed 2026-07-11.
Antoine Augustin Cournot was a French mathematician, philosopher, and economist who tried to bring mathematical rigor to economics at a time when the field was almost entirely verbal. In 1838 he published Researches into the Mathematical Principles of the Theory of Wealth, a book that was largely ignored in his lifetime and later recognized as foundational.
Cournot's instinct was that economic behavior could be modeled with equations, and he applied that instinct to one of the sharpest problems in economics: what happens when a small number of firms compete and each one's best move depends on what the others do.
Cournot analyzed a duopoly, two firms selling the same good, each choosing how much to produce. He saw that each firm's optimal output depends on the other's output, and he solved for the point where both firms are simultaneously making their best response to each other, so neither wants to change. That point, where every player's strategy is optimal given the others', is exactly what would later be called a Nash equilibrium.