Force, Cause, and Explanation: Euler and the Metaphysics of Science

Abstract

Euler is a centrally important figure in the history of modern philosophy, having indelibly shaped the metaphysics and epistemology of Enlightenment science. Yet Euler, best known for his many fundamental contributions to mathematics and physics, is little discussed in the philosophical scholarship. This dissertation demonstrates Euler’s importance to philosophy. I reveal and assess Euler’s contributions to major debates on causation and force, body and substance, the relation of metaphysics to science, and teleology, and argue that Euler’s interventions have major repercussions for the dominant philosophical traditions of his day – Cartesian, Leibnizian, and Newtonian.In Chapter 1, I open the question as to why he deserves the attention of philosophers, before reviewing the extant literature in philosophy and history of science and describing my own approach. Throughout this dissertation, I employ contextual philosophical analysis of the works of Euler and other figures connected to him, aiming to move beyond traditional historiographical categories that tend to slot figures into pre-fashioned molds. I also provide a brief historical survey of the early 18th century problem context surrounding force, causation, and explanation in physical theory, discussing the views of the three main figures mentioned above – Descartes, Leibniz, and Newton – and of key contemporaries of Euler’s. Chapter 2 treats Euler’s intervention into the complex, 18th century debates on force and causation in physics. I argue that Euler seeks to accomplish two things by conceptually engineering the physical notion of ‘force’. One is to resolve confusions in mechanical theory deriving from ambiguities persisting in physical theory following Newton and Leibniz. Second, he seeks to screen off mechanical theory from the reach of metaphysics, which improperly uses notions of ‘force’ for widely disparate explanatory aims. He dealt a blow both to the ‘Leibnizian-Wolffian’ as well as ‘Newtonian’ ontologies, and both philosophers and scientists through the course of the 18th century adapted themselves to his new picture of ‘force’ in science and metaphysics. Chapter 3 offers a new exposition and analysis of Euler’s foundations for physical theory. Euler intended to give a fundamental ontology of material body sufficient to ground mechanics, ostensibly a priori, since it was based on conceptual analysis, first principles, and definitions. Through close reconstruction, I ultimately find that Euler’s fundamental ontology did not succeed in providing an a priori basis of mechanics. However, I correct misinterpretations of the basis of his ontology, argue that his attempt succeeded to a greater extent than critics have given him credit for, and that he provided a major clarification of the logical structure of classical mechanics. In Chapter 4, I turn to final causation, or teleology, in relation to the principle of least action (PLA). Euler and Maupertuis based the PLA on ideas of the “economy” or “simplicity” of Nature and offered it as a foundation for physical theory alternative to the “mechanical” laws of motion descended from Newton. Some scholars have taken the PLA to evidence teleology’s survival into Enlightenment physics. Others claim that PLA-based teleology was refuted by philosophical attacks on the very concept of final causation. I argue that no narratives currently on offer fully capture the philosophical interest of the demise of PLA-based teleology. I show how that teleological metaphysics came to be refuted because it could not be coherently modeled in the mathematics. Hence, the metaphysics built on the back of the PLA was refuted directly through mathematization, and not by philosophical argument or empirical test, representing a radical reshuffling of epistemic authority regarding questions of basic ontology. Chapter 5 concludes and discusses directions for future work.