||動力学的力と力学的力 : カントの力の理論
Dynamical and Mechanical Force: Kant's Theory of Physical Force
42 , 2017-03-23 , 西日本応用倫理学研究会
Kant's Metaphysical Foundations of Natural Science (1786) consists of four chapters: Phoronomy, Dynamics, Mechanics, and Phenomenology. Force, the key concept of his theory of physics, is discussed in Dynamics and Mechanics. The distinction between dynamical and mechanical force is one of the crucial points of Kant's physics in the critical period. He argues that all mechanical laws presuppose dynamical laws because the former treat a moving force as matter moving through dynamical force. In this paper, I examine the historical background and the source of these distinctions. In contemporary physics, mechanics is the science of the moving body in general, and includes dynamics and statics. However, in Kant's period, the position of these disciplines in physics was not clear. Kant's Essay on Living Forces refers to both dynamics and mechanics, but this terminology is influenced by Wolff, who used both terms without clear classification. Given this situation in the pre-critical period, Kant's system, which claims that dynamics is superior to mechanics, is not consistent with his young age. He had noted two methods of physics, that is, dynamical and mechanical methods, in his lectures of metaphysics since the 1770s. The mechanical method, that is atomistic "Corpuscular philosophy", is represented by Epicurus and Descartes, while the dynamical approach is founded by Newton, and assumes the immanent force. In the 1780s, Kant argued that mechanical methods presupposed hypothetical absolute density and absolute empty. The model for the mechanical method is the theory of the confliction of perfectly elastic bodies. However, he accepted, even during his pre-critical periods, that a gravitational "action in distance" is unable to be explained by the model of confliction. Hence, it is necessary for his physics to assume the original immanent force. Thus, he must distinguish the mechanical force (F=mv) from the dynamical original force.