Baruch Spinoza’s (1632–77)Tractatus theologico-politicus (1669 or 1670) caused outrage across the Dutch Republic, for it obliterated the carefully installed separation between philosophy and theology. The posthumous publication of Spinoza’s Ethica, which is contained in his Opera posthuma (1677), caused similar consternation. It was especially the mathematical order in which the Ethica was composed that caused fierce opposition, for its mathematical appearance gave the impression that Spinoza’s heretical teachings were established demonstratively. In this essay, I document how the Dutch physician, local (...) politician, and amateur mathematician and experimenter Bernard Nieuwentijt (1654–1718) attempted to physico-mathematically and methodologically counter the threats posed by Spinoza’s program. Nieuwentijt tried to defend the authority of the scriptures in times at which they came under attack by the new philosophy and by the emerging sciences that were gradually winning terrain. The crux of his defense consisted in delineating a modest epistemology, a “learned ignorance,” that would cure Spinoza’s followers of their pansophical aspirations, on the one hand, and remove the conflict between the Bible and reason, on the other. The specific way in which he sought to accomplish this distinguished him from Dutch Reformed thought, or so I will argue. (shrink)

We apply Benacerraf’s distinction between mathematical ontology and mathematical practice to examine contrasting interpretations of infinitesimal mathematics of the seventeenth and eighteenth century, in the work of Bos, Ferraro, Laugwitz, and others. We detect Weierstrass’s ghost behind some of the received historiography on Euler’s infinitesimal mathematics, as when Ferraro proposes to understand Euler in terms of a Weierstrassian notion of limit and Fraser declares classical analysis to be a “primary point of reference for understanding the eighteenth-century theories.” Meanwhile, scholars like (...) Bos and Laugwitz seek to explore Eulerian methodology, practice, and procedures in a way more faithful to Euler’s own. Euler’s use of infinite integers and the associated infinite products are analyzed in the context of his infinite product decomposition for the sine function. Euler’s principle of cancellation is compared to the Leibnizian transcendental law of homogeneity. The Leibnizian law of continuity similarly finds echoes in Euler. We argue that Ferraro’s assumption that Euler worked with a classical notion of quantity is symptomatic of a post-Weierstrassian placement of Euler in the Archimedean track for the development of analysis, as well as a blurring of the distinction between the dual tracks noted by Bos. Interpreting Euler in an Archimedean conceptual framework obscures important aspects of Euler’s work. Such a framework is profitably replaced by a syntactically more versatile modern infinitesimal framework that provides better proxies for his inferential moves. (shrink)

Since the dawn of philosophy, the paradoxical interconnection between the continuous and the discrete plays a central rôle in attempts to understand the ontology of the world, while defying all attempts at consistent formulation. I investigate the relation between (classical) logic and concepts of “space” and “time” in physical and metaphysical theories, starting with the Greeks. An important part of my research consists in exploring the strong connections between paradoxes as they appear and are dealt with in ancient philosophy, and (...) their re-appearance in early modern natural philosophy, as well as in the foundations of contemporary science and mathematics. The way paradoxes are dealt with sheds light on a theory’s hidden metaphysical assumptions, especially with respect to matter, space, time and causation, it defines its ontological signature. This conclusion led me to the in-depth study of early modern natural philosophy, the origin of natural science, especially the influences ancient thinkers had on the new conceptions of space, time and causation developed by Newton, Huygens and Leibniz. (shrink)