 Similar points can be made about the rise of statistical physics, mentioned above in relation to Hacking’s work. (See also Brush 1983 and Porter 1986.) This was an explosion of work within the classical mechanical paradigm rather than a slow, puzzle-by-puzzle articulation of precisely that paradigm in its own previous terms. Or was it? For Kuhn himself recognized that modern mathematical physics only came into existence starting around 1850 and that Maxwellian electrodynamics was a major departure from the strictly Newtonian paradigm. In any case, there was much resistance among physicists to the new style of reasoning. The kinetic theory of gases quickly grew into statistical mechanics, which leapt the boundaries of its initial specialty field. New genres as well as new styles of mathematical-physical thinking quickly replaced old—and displaced the old generation of practitioners. Yet on Kuhn’s official theory of science it was all just “classical mechanics.”