In the history of thermodynamics, Ludwig Eduard Boltzmann (1844-1906) was an Austrian physicist and thermodynamicist, one of the central founders of statistical thermodynamics, developer of the probabilistic or logarithmic description of entropy, and noted for his 1886 postulate that "life is a struggle for entropy". [1]

Education
Boltzmann was awarded a doctorate from the University of Vienna in 1866 for a thesis on the kinetic theory of gases supervised by Josef Stefan. After obtaining his doctorate, he became an assistant to his teacher Josef Stefan. Boltzmann later taught at Graz, moved to Heidelberg and then to Berlin, where he studied under German physician and physicist Hermann von Helmholtz. [1]

Human statistical thermodynamics
His theories on the statistical measurement of entropy in gas-phase systems are the base of logic used in statistical human thermodynamics. One of his more famous postulates/quotes, stated in 1886, is that life is a struggle for entropy: [2]

“The general struggle for existence of animate beings is not a struggle for raw materials – these, for organisms, are air, water and soil, all abundantly available – nor for energy, which exists in plenty in any body in the form of heat Q, but of a struggle for entropy S, which becomes available through the transition of energy from the hot sun to the cold earth.”

These famous statement later stimulated Austrian physicist Erwin Schrödinger to argue, in 1944, that that “life feeds on negative entropy.” [5] This statement, in turn, spawned a number of new terms, such as neg-entropy and neguentropy, as well as debates on the logic of this statement. According to researchers Eric Schneider and Dorian Sagan, for instance, in regards to the correctness of this statement, “except for the term entropy, which is better replaced with Gibbs free energy G, Boltzmann’s analysis is essentially modern.” [3] In his famous 1872 article ‘Further Studies on the Thermal Equilibrium of Gas Molecules’, Boltzmann concluded, based on his comparison of humans to molecules as discerned through a reading of English Historian Henry Buckle’s 1861 book History of Civilization, that: [4]

“Molecules are like to many individuals, having the most various states of motion, and the properties of gases only remain unaltered because the number of these molecules which on average have a given state of motion is constant.”

References
1. Ludwig Boltzmann – Biographical Overview, Sam Houston State University, Texas.
2. Boltzmann, Ludwig. (1886). The Second Law of Thermodynamics. In B. McGinness, ed., Ludwig Boltzmann: Theoretical physics and philosophical problems: Seelct writings. Dordrecht, Netherlands: D. Reidel, 1974.
3. Schneider, Eric D. and Sagan, Dorion. (2005). Into the Cool - Energy Flow, Thermodynamics, and Life, (pgs. 59-60). Chicago: The University of Chicago Press.
4. (a) Boltzmann, Ludwig. (1872). “Weitere Studien über das Wärmegleichgewicht unter Gasmolekülen.” ('Further Studies on the Thermal Equilibrium of Gas Molecules'.) In Wisssenschaftliche Abhandlungen, ed. F. Hasenohrl, vol.1, pg. 317. J.A. Barth, Leipzig, 1909.
(b) Thims, Libb. (2008). The Human Molecule, (preview), (pg. 8-9). Morrisville, NC: LuLu.
5. (a) Schrödinger, Erwin. (1944). What is Life? (ch. 6 “Order, Disorder, and Entropy). pgs. 67-75 Cambridge: Cambridge University Press.
(b) What is Life? (1944 book in word doc download).

Further reading
● Cercignani, Carlo. (1998). Ludwig Boltzmann - the Man Who Trusted Atoms. Oxford: Oxford University Press.
● Lindley, David. (2001). Boltzmann's Atom - the Great Debate that Launched a Revolution in Physics. New York: The Free Press.