摘要：John Neville Keynes uses a diagrammatic method, adapted of Euler’s diagrammatic method, in which the semantic content of a categorical judgment is associated to a proper subset of a set of basic diagrams. Different syllogistics are characterized by different sets of basic diagrams. We compare, by Keynesian diagrammatic method, three syllogistics (all of them with existential presupposition and with “non universal” presupposition of terms) as to validity of immediate inferences: the syllogistic without negative terms, the syllogistic with negative terms in which a term and its corresponding negative term complement each other in relation to the universe of discourse, and the syllogistic with negative terms in which a term and its corresponding negative term does not necessarily complement each other in relation to the universe of discourse.
其他摘要：John Neville Keynes uses a diagrammatic method, adapted of Euler’s diagrammatic method, in which the semantic content of a categorical judgment is associated to a proper subset of a set of basic diagrams. Different syllogistics are characterized by different sets of basic diagrams. We compare, by Keynesian diagrammatic method, three syllogistics (all of them with existential presupposition and with “non universal” presupposition of terms) as to validity of immediate inferences: the syllogistic without negative terms, the syllogistic with negative terms in which a term and its corresponding negative term complement each other in relation to the universe of discourse, and the syllogistic with negative terms in which a term and its corresponding negative term does not necessarily complement each other in relation to the universe of discourse.
关键词：Negative terms;J. N. Keynes;Diagrammatic method;Extension versus Intension;Termos negativos;J. N. Keynes;Método diagramático;Extensão versus Intensão
