2023-01-272023-01-272018-06CARVALHO, André Cutrim; CARVALHO, David Ferreira. O princípio da demanda efetiva de Keynes como contra-ataque definitivo à Lei de Say dos economistas (neo)clássicos. Economia-Ensaios, online, v. 32, n. 2, p. 223-247, jun. 2018. DOI: https://doi.org/10.14393/REE-v32n2a2018-9. Disponível em: http://repositorio.ufpa.br:8080/jspui/handle/2011/15210. Acesso em:.1983-1994https://repositorio.ufpa.br/handle/2011/15210In General Theory, Keynes presented his understanding of the Principle of Effective Demand. For this, he developed a new conceptual taxonomy, which brought difficul ties to the understanding of the new message contained in his Work, especially for those economists trained in the tradition of (neo) classical orthodoxy. Therefore, the fundamental objective of this paper is to present Keynes’s Principle of Effective De mand as a definitive counterattack to Say’s (neo) classical economists. The true proof of the validity of the General Theory is not logic, not facts, but the usefulness of its application in the real world in which we live.Acesso Abertohttp://creativecommons.org/licenses/by-nc-nd/3.0/br/Teoria geralKeynesPrincípio da Demanda EfetivaGeneral theoryPrinciple of Effective DemandArtigo de Periódico10.14393/REE-v32n2a2018-9