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Document Details : Title: Genèse de la causalité physique Author(s): PATY, M. Journal: Revue Philosophique de Louvain Volume: 102 Issue: 3 Date: Août 2004 Pages: 417-445 DOI: 10.2143/RPL.102.3.504930 Abstract : The notions or categories of causality and determinism have accompanied the formation of modern sciences, and primarily those of physics. Current usage nowadays often tends wrongly to confuse them in the reevaluations to which they are submitted in physics itself. In this article the A. seeks to clarify the first of these notions, more precisely physical causality, by following up its development from the beginnings of dynamics, through its first uses and conceptualisations that accompany the mathematisation of mechanics, before its extension to physics in general. We will see how, while being supported by one of the traditional philosophical aspects of the idea of causality (that of «efficient cause»), physical causality breaks with the metaphysical meaning that was previously attached to it. Rather more than in Newton’s Principia, as usually thought, it is in the re-elaboration by d’Alembert, in his Treatise of Dynamics, of the laws of motion considered as principles, and expressed by differential calculus, that the idea of physical causality is explicitly considered indissociable from its effect, that is the change of motion. The respective thought of Newton and d’Alembert in regard to the notions of cause and force are, in this respect, in opposition concerning the properly physical nature of this change. The change of motion was viewed by d’Alembert as immanent to motion, for its cause could be circumscribed by its effect, whereas it remained mathematical and metaphysical in the Newtonian conception of external force taken as a mathematical substitute for causes, which was the common way to consider forces before Lagrange’s analytical mechanics. It is the physical conception inherited from d’Alembert, thereafter to prevail through Lagrangean analytical mechanics, that made it possible to re-integrate physically and rationally the concept of force in its Eulerian differential transcription. Further avatars of the notion of causality, that include relativist causality and developments in regard to determinism, are dealt with in a separate investigation. |
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