The reversibility paradox was pointed out by Austrian physical chemist Joseph Loschmidt in 1876 to Austrian physicist Ludwig Boltzmann in commentary on his 1872 paper on his H-theorem. In short, Loschmidt said that the H-theorem singled out the direction in time in which H decreases, whereas the underlying mechanics was the same whether time flowed forwards or backwards. [2]

Thought experiment

In 1876, in sum, Loschmidt suggested a (

Now suppose at 12:05, the ‘hand of God’ (fact check) reverses the direction of all the molecules. It follows from reversibility that at exactly 12:10 all the molecules must return to the corner of the room. Surely its entropy must also have the same value as at the beginning. Yet Boltzmann’s H-theorem suggests that entropy has increased continuously. Loschmidt noted that there seems to be a contradiction.

Boltzmann, supposedly, responded (fact check) to this by asserting that the H-theorem is a statistical statement, which must be true in the overwhelming majority of scenarios because the number of microstates associated with equilibrium is overwhelmingly greater than the number associated with any

See also

● Poincaré recurrence theorem

References

1. Boltzmann, Ludwig. (1877). “On the Relation of a General Mechanical Theorem to the Second Law of Thermodynamics” (“Uber die Beziehung eines Allgemeine Mechanischen Satzes zum zweiten Hauptsatze der Warmetheorie”),

2. Flamm, Dieter. (1999). “Boltzmann: a Disordered Genius”,

3. Ayres, Robert U. (1994).

External links

● Loschmidt’s paradox – Wikipedia.