born Jan. 5, 1767, Lyon, France
died Nov. 15, 1832, Paris
French economist.
He edited a magazine and started a spinning mill before joining the faculty of the Conservatory of Arts and Crafts (1817–30) and the Collège de France (1830–32). In his major work, A Treatise on Political Economy (1803), he advanced his law of markets, which claims that supply creates its own demand. He attributed economic depression not to a general deficiency in demand but rather to temporary overproduction for some markets and underproduction for others, an imbalance that must automatically adjust itself as overproducers redirect their production to conform with consumers' preferences. Say's law remained a central tenet of orthodox economics until the Great Depression .