2022-11-252022-11-252013-12CARVALHO, André Cutrim; CARVALHO, David Ferreira. As críticas de Karl Marx e John Maynard Keynes à teoria (neo)clássica. Cadernos CEPEC, online, v. 2, n. 12, p. 1-31, dez. 2013. DOI: http://dx.doi.org/10.18542/cepec.v2i7-12.6867. Disponível em: http://repositorio.ufpa.br:8080/jspui/handle/2011/15051. Acesso em:.2238-118Xhttps://repositorio.ufpa.br/handle/2011/15051Say's Law is nothing more than a principle or axiom that today serves as a basis to support the theoretical framework of neoclassical economics. The criticism against this principle in Keynes's General Theory was so overwhelming that eventually causing a division in economics: classical economics (sustained by the principle Say) and saving Keynes (underpinned by the principle of effective demand). In this context, this paper discusses the original formulation of Say's Law, as the basic principle of sustaining the economy of the classical and neoclassical, and its connection with the formulation of the Law of Walras, as well as presenting the criticism that John M. Keynes and Karl Marx did to this axiom.Acesso Abertohttp://creativecommons.org/licenses/by-nc-nd/3.0/br/Lei de SayEconomia clássicaJohn Maynard Keynes e Karl MarxSay’s LawClassical economicsArtigo de Periódico10.18542/cepec.v2i7-12.6867