WIT Press

The origins of irreversibility


Free (open access)


Volume 2 (2007), Issue 3



Page Range

165 - 169

Paper DOI



WIT Press


E. Tiezzi, N. Marchettini


This article is a theoretical contribution dedicated to Boltzmann's theorem revisited in light of the studies of Mario Ageno, late professor of Physics at the University of Rome (La Sapienza), who showed an interesting new point of view on probability and uncertainty in his book The Origins of Irreversibility. The discussion takes into account the equation of Ilya Prigogine, Nobel Prize winner in Chemistry, for the calculation of entropy production per unit time. The main point is that the authors claim that there are three different conditions: (a) the tendency towards disorder (Boltzmann) as in the case of gas; (b) the Ageno contribution related to the collisions of molecules against the walls: in this case Ageno claims that the origin of irreversibility derives from the tendency towards a macrostate richer in microstates; (c) the presence in the liquids, living systems and water of possible dissipative structures: in this case self-organization is the most probable state (Prigogine's order out of chaos) and the tendency is towards an ordered state.


Boltzmann's theorem, entropy, irreversibility, order out of chaos