Irreversibility



For the concept in evolutionary theory, see Dollo's law

In science, a process that is not reversible is called irreversible. This concept arises most frequently in processes. Irreversibility is also used in economics to refer to investment or expenditures that involve large sunk costs.[1]

From a thermodynamics perspective, all natural processes are irreversible. The phenomenon of irreversibility results from the fact that if a dissipation due to intermolecular friction and collisions; energy that will not be recoverable if the process is reversed.

Absolute versus Statistical reversibility

Thermodynamics defines the statistical behaviour of large numbers of entities, whose exact behavior is given by more specific laws. Since the fundamental laws of physics are all time-reversible,[2] it can be argued that the irreversibility of thermodynamics must be statistical in nature, that is, that it must be merely highly unlikely, but not impossible, that a system will lower in entropy.

History

The German physicist Rudolf Clausius, in the 1850s, was the first to mathematically quantify the phenomenon of irreversibility in nature through his introduction of the concept of entropy. In his 1854 memoir “On a Modified Form of the Second Fundamental Theorem in the Mechanical Theory of Heat” Clausius states:

“ It may, moreover, happen that instead of a descending transmission of heat accompanying, in the one and the same process, the ascending transmission, another permanent change may occur which has the peculiarity of not being reversible without either becoming replaced by a new permanent change of a similar kind, or producing a descending transmission of heat. ”

Complex Systems

The difference between reversible and irreversible events has particular explanatory value in complex systems (such as living organisms, or ecosystems). According to the biologists Humberto Maturana and Francisco Varela, living organisms are characterized by autopoiesis, which enables their continued existence. More primitive forms of self-organizing systems have been described by the physicist and chemist precautionary principle can be defined with reference to the concept of reversibility.

Notes

  1. ^ http://links.jstor.org/sici?sici=0022-0515(199109)29%3A3%3C1110%3AIUAI%3E2.0.CO%3B2-I R. S. Pindyck Irreversibility, Uncertainty, and Investment, Journal of Economic Literature, Vol. 29, No. 3 (Sep., 1991), pp. 1110-1148
  2. ^ David Albert on Time and Chance

See also
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Irreversibility". A list of authors is available in Wikipedia.