O que há de metafísica na mecânica do século XVIII?

Abstract

Unlike the period of creation of the so-called modern science, the eighteenth century seems not to play a key role in the development of physics. In the view of many authors, the Age of Enlightenment is considered as an era dedicated to the organization of mechanics, which culminated in the works of Lagrange, immediately preceded by Euler and d'Alembert. Many authors claim that the formulation of rational mechanics gradually eliminated metaphysics and theology and also that the emergence of modern physics was accompanied by a rejection of Aristotelian metaphysics of substance and quality, form and matter, potentiality and actuality. The focus of the thesis is to show that in the eighteenth century some natural philosophers that engaged in the construction of mechanics were concerned about determining how it would be possible to describe the phenomena through mathematics. In general, the mechanistic philosophy demanded that the observed changes in the natural world could be explained only in terms of movement and rearrangement of particles of matter, since the predecessors of the Enlightenment, philosophers were able to partly eliminate the concept of natural philosophy final causes and most Aristotle shape and concepts of substance, for example. However, the mechanistic philosophers disagreed about the causes of motion. What would make a body move? An external force? An internal force? No force? All these ideas had their supporters and all suggested philosophical reflections which exceeded the limits of the natural sciences . Moreover, concepts like space, time, force, mass and inertia, for example, are essential concepts of mechanics that represent a reality. But how the manifestation of this reality becomes possible? How these concepts have been defined? Although we can not find an explicit philosophical discussion in many books that deal with the mechanics, such implicit attitudes are evident when dealing with issues such as the ambition to universality and application of mathematics. Galileo had motivations and reasons for claiming that the book of nature is written in a mathematical language. However, even though mathematics has become the language of physics, we show in this thesis that the second can not be reduced to the first. In the light of this research we may speak of rational mechanics as an agent of rationality with the purpose of organizing and structuring observable data obtained through experimentation. However, we show that this science was not obtained without subjective assumptions and conventions as natural philosophers claimed it would be. Behind an explanatory and descriptive representation of the phenomena of nature and internal consistency of their own "confirmed" through mathematics content, verified the presence of metaphysics.