Boltzmann order-disorder principle

In thermodynamics, Boltzmann order-disorder principle, a term originating in Erwin Schrodinger’s famous 1943 What is Life? lecture-turned-book, his rebuttal Note to Chapter 6 in particular, refers to the model (see: entropy models) of the magnitude of entropy being representative of the atomic order or disorder of any given material body or system, the logic of which is embodied in the Boltzmann-Planck entropy (Boltzmann entropy) equation: [1]

S = k log W

where S is the entropy, k the Boltzmann constant, and W the multiplicity or probability of the various microstates of the particles of the given body (order associated with low probability; disorder associated with high probability). [2] The logic of this, historically, originated in the 1870s H-theorem work of Ludwig Boltzmann (and later black body theory modifications of this by Max Planck), and prior to this in the 1860s disgregation theory models (precursors to entropy) of Rudolf Clausius and the velocity distribution work of James Maxwell (see: Maxwell-Boltzmann distribution) regarding the temperature of bodies and the average velocities of its particles (see: kinetic theory).

Free energy
In Schrodinger's lecture he attempted to argue that "life" is something that "feeds on negative entropy", a comment that was latter attacked by his fellow colleagues (including Linus Pauling, Max Perutz, and F. Simon, among others), after which he was forced to reply that if he were catering to the hard physical science community rather than the lay audience, he would have turned the discussion to free energy, which he defined as follows: [1]

Free energy is a highly technical, rather intricate concept, whose relation to the Boltzmann order-disorder principle is less easy to trace.”

Indeed, there is much truth in this statement.

See also
Principle of elementary disorder
Boltzmann brain problem
Boltzmann chaos assumption
Boltzmann formula
Boltzmann tombstone

1. Schrodinger, Erwin. (1944). What is Life? (pg. 74). Cambridge University Press.
2. Rigden, John S. (2005). Einstein 1905: the Standard of Greatness (pg. 30). Harvard University Press.

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