ABSTRACT
This essay in honour of Peter Groenewegen is devoted to the history of Say’s law. The differences of opinion on the interpretation of the law are reflected in the contradictory names given to the theorem. During most of the nineteenth century, the description ‘théorie des débouchés’ (‘law of markets’) is used (Blanqui, II, 1845:198; Coquelin 1854:653). In 1892, Dubois de l’Estang used the wording ‘loi fondamentale’ (Dubois de l’Estang 1892:653). Afterwards, the dominant description reads ‘Say’s law’ (Keynes 1936:26; Schumpeter 1954:615; Shackle 1967:136), but also in use are expressions like ‘Say’s identity’ (Becker and Baumol 1952:374; Patinkin 1956:119; Patinkin 1989:193; Blaug 1962:137; Blaug 1996:148; Kuenne 1963:308), ‘Say’s proposition’ (Skinner 1969:182), ‘Say’s equality’ (Patinkin 1956:119; Patinkin 1989:193; Blaug 1962:131; Blaug 1996:148), and ‘Say’s theorem’ (Skinner 1969:184).
