Physicist, b. 20 February 1844 (Vienna, Austria), d. 5 September 1906 (Duino, Italy)
Ludwig Boltzmann was the son of an Imperial and Royal Cameral-Concipist (tax official). He attended school in Linz and entered the University of Vienna to study physics. He received his doctorate in 1866, gave his inaugural address as Privatdozent (lecturer) in 1867 and was appointed Professor of Mathematical Physics at the University of Graz.
During the following years Boltzmann developed his career through periods of teaching at various universities. He spent several months at the University of Heidelberg in 1869 and several months again in Berlin in 1871. From 1873 to 1876 he was Professor of Mathematics at the University of Vienna. He then returned to Graz to take the chair of Experimental Physics. He was now well known in the scientific world of the continent, and students from all over Europe came to study with him.
In 1893 Boltzmann became Professor of Theoretical Physics at the University of Vienna. In 1900 he accepted an invitation from the University of Leipzig but returned to Vienna in 1902 with the promise - and on the condition - never to accept another invitation again. From 1903 he lectured not only on physics but also on questions of philosophy under the title "Methods and General Theory of the Natural Sciences." These lectures became famous; the audience grew to such an extent that even the largest lecture hall of the university could not accommodate it, and Emperor Franz Joseph invited Boltzmann to give lectures at the palace.
Boltzmann was among the first scientists who recognised the importance of Maxwell's electromagnetic theory. His major contribution to science was the invention of statistical mechanics, which connects the properties and behaviour of atoms and molecules with the large scale properties such as viscosity and heat of the substances of which they were the building blocks. Boltzmann used probability theory to describe how the properties of atoms determine the properties of matter. In 1871 he showed that the average energy of motion of a molecule is the same in all directions, a result now known as the Maxwell-Boltzmann distribution.
The Second Law of Thermodynamics states that a system can only go from an organized state to a less organized state (can only increase its entropy), which means that thermal processes are irreversible. Boltzmann's derivation of the Law from the general principles of mechanics in 1890 created a big debate among scientists because the equations of Newtonian mechanics are reversible in time. Poincaré showed mathematically that a mechanical system in a given state will return infinitely often to a state arbitrarily close to its original state. Boltzmann said that Poincaré's result was a mathematical limit that is impossible to reach in practice since the time before a system returns to near its original state was too long. But he accepted that there can be the statistically rare situations when entropy can decrease.
The controversy raged for many years and often took the form of personal attack, and conflict with colleagues was one of the reasons for Boltzmann's frequent change of employer. A paper by Wilhelm Oswald given at a meeting in Lübeck stated that "The actual irreversibility of natural phenomena thus proves the existence of processes that cannot be described by mechanical equations, and with this the verdict on scientific materialism is settled." The ensuing debate between Oswald and Boltzmann was described by the congress participant Arno Sommerfeld:
This was in 1895, but Boltzmann continued to be violently attacked for his teachings, to the degree that during his years in Leipzig he attempted suicide. A few years later, during a holiday with his wife and daughter at the Bay of Duino near Trieste, he hanged himself while his wife and daughter were swimming. Whether he was driven by despair over the lack of acceptance of his theories or by mental depression, his death came just at the time when his statistical approach of molecular motion was proven to be correct by nuclear physics.
Boltzmann's despair can be heard in his words, written in the year before his death: "May I be excused for saying with banality that the forest hides the trees for those who think that they disengage themselves from atomistics by the consideration of differential equations." His name lives on in the Ludwig-Boltzmann-Gesellschaft, one of Austria's major research organizations.
O'Connor, J. J. and E. F. Robertson (1998) Ludwig Boltzmann, School of Mathematics and Statistics, University of St Andrews, Scotland,
http://www-history.mcs.st-andrews.ac.uk/Mathematicians/Boltzmann.html (accessed 15 June 2004)