by PhilipJ on 7 December 2006
I’ve just finished reading David Lindley’s biography of Ludwig Boltzmann, called Boltzmann’s Atom. He’s quite fascinating, because while other prominent scientists of his day often had a myriad of interests, Boltzmann’s entire career spanning some 30 years was spent almost exclusively on understanding the properties of gases. He firmly believed that atoms were real (a highly contested idea largely until the work of Einstein on diffusion), and battled with Ernst Mach who took an ultra-realist philosophy towards science: theorising in general he frowned upon, and he doubly hated theoretical work with constructs that he felt you could never possibly see, even in principle. Boltzmann’s kinetic theory, relying on atoms which obeyed Newtonian mechanics, was a common Machian example of exactly how theoretical physics was heading down an incorrect path.
Near the end of his life, however, Boltzmann also became interested in Darwin’s ideas, and life as a perfect example of thermodynamics. Now we commonly think about entropy when discussing almost all aspects of biological physics, so it was very prescient for Boltzmann to say, in 1900:
The overall struggle for existence of living beings is therefore not a struggle for raw materials—the raw materials of all organisms are available in excess in the air, water, and ground—nor for energy, which in the form of heat is plentiful in every body, but rather a struggle for entropy, which becomes available in the flow of energy from the hot sun to the cold earth.