Galileo (1623) already had suggested that the analysis of phenomena like heat and pressure could be reduced to the study of movements of elementary particles. Within the empirical methodology this could be conceived as the question how the sensory experience of the secondary quality of heat of an object or a gas could be reduced to movements of particles. Bernoulli (Hydrodynamica published in 1738) was the first to develop a kinetic theory of gases in which macroscopically observable phenomena a