The widespread idea that infinitesimals were “eliminated” by the “great triumvirate” of Cantor, Dedekind, and Weierstrass is refuted by an uninterrupted chain of work on infinitesimal-enriched number systems. The elimination claim is an oversimplification created by triumvirate followers, who tend to view the history of analysis as a pre-ordained march toward the radiant future of Weierstrassian epsilontics. In the present text, we document distortions of the history of analysis stemming from the triumvirate ideology of ontological minimalism, which identified the continuum (...) with a single number system. Such anachronistic distortions characterize the received interpretation of Stevin, Leibniz, d’Alembert, Cauchy, and others. (shrink)

Les Principes de la connaissance humaine sont l'occasion pour Berkeley de nier l'existence des idées générales abstraites. Il admet cependant l'existence d'idées générales, plus exactement d'idées déterminées à signification générale. C'est ainsi qu'il peut rendre compte de la généralité de certaines démonstrations. L'exemple choisi est celui de l'idée de triangle dans le cadre d'une démonstration géométrique. Mais peut-on également rendre compte de cette manière des démonstrations et des idées algébriques et notamment celle de quantité? In the Principles of human knowledge, (...) Berkeley clearly denies the existence of abstract general ideas. He assumes, however, the existence of general ideas or, more exactly, of determinate ideas with a general meaning. In this way, he explains the generality of certain demonstrations. He chooses the example of the idea of a triangle within a geometrical demonstration. But can he likewise account for algebraic demonstrations and ideas, and in particular for the idea of quantity? (shrink)

We advance a theory of the representational role of Euclidean diagrams according to which they are samples of co-exact features. We contrast our theory with two other conceptions, the instantial conception and Macbeth’s iconic view, with respect to how well they accommodate three fundamental constraints on theories of the Euclidean diagrammatic practice— that Euclidean diagrams are used in proofs whose results are wholly general, that Euclidean diagrams indicate the co-exact features that the geometer is allowed to infer from them and (...) that Euclidean diagrams play the same role in both direct proofs and indirect proofs by reductio—and argue that our view is the one best suited to account for them. We conclude by illustrating the virtues of our conception of Euclidean diagrams as samples by means of an analysis of Saccheri’s quadrilateral. (shrink)