Summary Descartes' two treatises of corpuscular-mechanical natural philosophy—Le Monde (1633) and the Principia philosophiae (1644/1647)—differ in many respects. Some historians of science have studied their significantly different theories of matter and elements. Others have routinely noted that the Principia cites much evidence regarding magnetism, sunspots, novae and variable stars which is absent from Le Monde. We argue that far from being unrelated or even opposed intellectual practices inside the Principles, Descartes' moves in matter and element theory and his adoption of (...) wide swathes of novel matters of fact, were two sides of the same coin—that coin being his strategies for improving the systematic power, scope and consistency of the natural philosophy presented in the Principia. We find that Descartes' systematising strategy centred upon weaving ranges of novel matters of fact into explanatory and descriptive narratives with cosmic sweep and radical realist Copernican intent. Gambits of this type have recently been labelled as ‘cosmographical’ (the natural philosophical relating of heavens and earth in contemporary usage). Realist Copernican natural philosophers, from Copernicus himself, through Bruno, Gilbert and Galileo did this to varying degrees; but, we suggest, Descartes presented in Books III and IV of the Principia the most elaborate and strategically planned version of it, underneath the ostensible textbook style of the work. (shrink)

El tratado hidrostático fue uno de los primeros textos de Descartes, fruto de su decisivo encuentro con Isaac Beeckman. En este artículo, analizaremos cómo fue concebido y los motivos que llevaron a Descartes a cuestionar alguno de los aspectos fundamentales de la física matemática de Beeckman. Este episodio está íntimamente relacionado con la independencia de las disciplinas matemáticas y su aplicación a cuestiones propias de la filosofía natural.Descartes’ hydrostatic treatise was one of his first text, fruit of his crucial meeting (...) with Isaac Beeckman. In this article, we will analyse how it was conceived and the reasons which leaded Descartes to question some fundamental aspects of Beeckman’s Physico-mathematics. This subject is closely connected with theautonomy and implementation of mathematical sciences to typical matters of natural philosophy. (shrink)

Descartes’s most extensive discussion of the law of refraction and the shape of the anaclastic lens is contained in Rule 8 of "Rules for the Direction of the Mind". Few reconstructions of Descartes’s discovery of the law of refraction take Rule 8 as their basis. In Rule 8, Descartes denies that the law of refraction can be discovered by purely mathematical means, and he requires that the law of refraction be deduced from physical principles about natural power or force, the (...) nature of the action of light, and the behavior of light rays in a variety of transparent media. For over a century, however, there has been broad agreement that Descartes discovered the law of refraction by purely mathematical means, and that he only later provided the relevant physical rationale (via comparisons or analogies) in Dioptrics II. I execute each step in Descartes’s proposed deduction of the law of refraction and the shape of the anaclastic lens in Rule 8 and concretely show how Descartes could have discovered the law of refraction and the shape of the anaclastic by its means. Rule 8, I argue, reflects Descartes’s actual path to the discovery of the law of refraction and the shape of the anaclastic lens. (shrink)

It is instructive to view the scientific revolution from the point of view of Robert Boyle’s distinction between intermediate and ultimate causes. From this point of view, the scientific revolution involved the identification of intermediate causes and their investigation by way of experiment as opposed to the specification of ultimate causes of the kind involved in the corpuscular matter theories of the mechanical philosophers. The merits of this point of view are explored in this paper by focussing on the hydrostatics (...) of Pascal and Boyle, understood as the experimental investigation of the action of the intermediate causes weight and pressure. The distinctive features of this new science are highlighted by comparing it with two alternative versions of hydrostatics, that of Stevin and that of Descartes. (shrink)

In this reassessment of Descartes' debt to his mentor Isaac Beeckman, I argue that they share the same basic conception of motion: the force of a body's motion—understood as the force of persisting in that motion, shorn of any connotations of internal cause—is conserved through God's direct action, is proportional to the speed and magnitude of the body, and is gained or lost only through collisions. I contend that this constitutes a fully coherent ontology of motion, original with Beeckman and (...) consistent with his atomism, which, notwithstanding Descartes' own profoundly original contributions to the theory of motion, is basic to all Descartes' further work in natural philosophy. (shrink)