Negentropy

From Wikipedia, the free encyclopedia

In 1943 Erwin Schrödinger used the concept of “negative entropy” in his popular-science book What is life?. Later, Léon Brillouin shortened the expression to a single word, negentropy. Schrödinger introduced the concept when explaining that a living system exports entropy in order to maintain its own entropy at a low level (see entropy and life). By using the term negentropy, he could express this fact in a more "positive" way: a living system imports negentropy and stores it.

In a note to What is Life? Schrödinger explains his usage of this term.

“ Let me say first, that if I had been catering for them [physicists] alone I should have let the discussion turn on free energy instead. It is the more familiar notion in this context. But this highly technical term seemed linguistically too near to energy for making the average reader alive to the contrast between the two things. ”

In 1974, Albert Szent-Györgyi proposed replacing the term negentropy with syntropy, a term which may have originated in the 1940s with the Italian mathematician Luigi Fantappiè, who attempted to construct a unified theory of the biological and physical worlds. (This attempt has not gained renown or borne great fruit.) Buckminster Fuller attempted to popularize this usage, though negentropy still remains common.

[edit] Information theory

In information theory, "negentropy" is used as a measure of distance to normality. Consider a signal with a certain distribution. If the signal is Gaussian, the signal is said to have a normal distribution. Negentropy is always positive, is invariant by any linear invertible change of coordinates, and vanishes iff the signal is Gaussian.

Negentropy is defined as

J(p_x) = S(\phi_x) - S(p_x)\,

where S(φx) stands for the Gaussian density with the same mean and variance as px and S(px) is the differential entropy:

S(p_x) = - \int p_x(u) \log p_x(u) du

Negentropy is used in statistics and signal processing. It is related to network entropy, which is used in Independent Component Analysis.[1]

[edit] Organisation theory

In risk management, negentropy is the force that seeks to achieve effective organisational behaviour and lead to a steady predictable state.[2]

[edit] Notes

  1. ^ P. Comon, Independent Component Analysis - a new concept?, Signal Processing, 36:287-314, 1994.
  2. ^ Pedagogical Risk and Governmentality: Shantytowns in Argentina in the 21st Century (see p. 4).
 This evolution-related article is a stub. You can help Wikipedia by expanding it.
 This thermodynamics-related article is a stub. You can help Wikipedia by expanding it.
Retrieved from "http://en.wikipedia.org../../../n/e/g/Negentropy.html"