Galileo's matter theory: resolutio and infinite indivisibles

TULA MOLINA, FERNANDO

History and Philsosophy of Physics in the South Cone

College Publications

Lugar: Londres; Año: 2013; p. 143 - 161

In "Atomism and its Critics" (1997), Andrew J. Pyle points out that: "The cohesiveness of fluids also poses a mayor problem for the matter-theory of Galileo´s Solid bodies, he claims in Day One of the Discorsi, are held together by the "fuga vacui" exerted by their interstitial microvacua; liquids such as water lack such point-vacua and are therefore without cohesion. (The melting of a solid body he explains in terms of fire-atoms or ignicoli into the interstitial vacua to neutralize their fuga vacui). Galileo continued to deny, in the face of some powerful evidence, that a fluid such as water possessed surface tension; such an admission would have proved fatal to his matter-theory. The main problem of any atomistic theory is the explanation of body cohesion. In the above citation Pyle correctly specifies that, in Galileo´s case, the problem was to explain the cohesion of fluids (or, more properly, its lack of cohesion). This point is, in my opinion, no only right but much deeper than general comments like, for example, that of A. Mark Smith (1976) who states that: "It appears that the confluence of powerful physical, metaphysical and mathematical trends lead Galileo to his theory of indivisibles. Here, the empirical and conceptual difficulties that Galileo had to face disappear under the mere enunciation of the convergent traditions behind him. Moreover, Pyle´s citation has,to my ends, the advantage to involve briefly all the points of Galileo?s atomism that I want to comment in the following: 1. The relationship between cohesion of fluids and Galileo´ss matter theory. 2. The cause of cohesion and dissolution of solid bodies. 3. Galileo´s conception of fluids 4. The problem of surface tension and Galileo´s atomism. 5. The relationship between theory and evidence.