In De gravitatione, Newton contends that Descartes' physics is fundamentally untenable since the "fixed" spatial landmarks required to ground the concept of inertial motion cannot be secured in the constantly changing Cartesian plenum. Likewise, it is has often been alleged that the collision rules in Descartes' Principles of Philosophy undermine the "relational" view of space and motion advanced in this text. This paper attempts to meet these challenges by investigating the theory of connected gears (or "kinematics of mechanisms") for a (...) potential Cartesian method of positing the permanent reference frames necessary to uphold Descartes' conservation law for the quantity of motion. In particular, the insights gained from an examination of the kinematics of mechanisms will provide the Cartesian with much needed resources to counter the two threats posed above. (shrink)

This paper is part II of a trilogy on the transition from classical particle mechanics to relativistic continuum mechanics that one of the authors is working on. The first part, on the Trouton experiment, was published in the Stachel festschrift (Janssen 2003). This paper focuses on the Lorentz-Poincaré electron, and, in particular, on the "Poincaré pressure" or "Poincaré stresses" introduced to stabilize the electron. It covers both the original argument by Poincaré (1906) and a modern relativistic argument for adding a (...) negative pressure term to the system's energy-momentum tensor inspired by the work of Laue (1911a, b). It highlights the importance of a paper by Lorentz (1899) in this context and of the "electromagnetic mechanics" of Abraham (1903). (shrink)

The ArgumentIn spite of Koyré's conclusions, there are sufficient reasons to claim that Galileo, and with him the beginnings of classical mechanics in early modern times, was closely related to practical mechanics. It is, however, not completely clear how, and to what extent, practitioners and engineers could have had a part in shaping the modern sciences. By comparing the beginnings of modern dynamics with the beginnings of statics in Antiquity, and in particular with Archimedes — whose rediscovery in the sixteenth (...) century was of great consequence — I will focus on the question of which devices played a comparable role in dynamics to that of the lever and balance in statics. I will also examine where these devices came from. In this way, I will show that the entire world of mechanics of that time — “high” and “low,” practical and theoretical — was of significance for shaping classical mechanics and that a specific relationship between art and science was and is constitutive for modern sciences. (shrink)

Peter Dear ha proporcionado recientemente un análisis de la transformación que sufrió el recurso a la experiencia en la filosofía natural del siglo XVll. De la experiencia de lo cotidiano se pasa a la descripción detallada de una experiencia artificial irrepetible, localizada espacio-temporalmente y producida por instrumentos más o menos complejos. EI artículo explora dicha interpretación en referencia a la construcción de la ciencia del movimiento de Galileo, mediante un análisis dcl experimento del plano inclinado que se describe en los (...) Discorsi y un manuscrito, y concluye que la interpretacion de Dear dificulta considerablemente la caracterización de la práctica de Galileo.Peter Dear has recently put forward an analysis of th transformation underwent by the appeal to experience in Seventeenth-Century natural philosophy. According to Dear, this transformation lies in the change from common experience to the detailed description of an unrepeatable artificial experience space temporally located and produced by more or less sophisticated instruments. This paper explores Dear’s interpretation with regard to the construction of Galileo’s science of motion, by analyzing the celebrated inclined plane experiment described in the Discorsi as well as one of Galileo's manuscripts and concludes that Dear’s interpretation makes very difficult the characterization of Galileo’s practice. (shrink)