space picture bastion_logo picture

space picture





space picture


aka Order, Autopoesis, Negentropy, Extropy

Lovelock on Negentropy (Inverse Entropy, Negative Entropy)

"The great physicist Ludwig Boltzmann expressed the meaning of the second law in an equation of great seemliness and simplicity: S=k(lnP), where S is that strange quantity entropy; k is a constant rightly called the Boltzmann constant; and lnP is the natural logarithm of the probability. It means what it says--the less probable something is, the lower its entropy. The most improbable thing of all, life, is therefore to be associated with the lowest entropy. Schrödinger was not happy to associate something as significant as life with a diminished quantity, entropy. He proposed, instead, the term 'negentropy,' the reciprocal of entropy--that is, 1 divided by entropy or 1/S. Negentropy is large, of course, for the improbable things like living organisms. To describe the burgeoning life of our planet as improbable may seem odd. But imagine that some cosmic chef takes all the ingredients of the present Earth as atoms, mixes them, and lets them stand. The probability that those atoms would combine into molecules that make up our living Earth is zero. The mixture would react chemically to form a dead planet like Mars or Venus."

"... If the second law tells us that entropy in the Universe is increasing, how does life avoid the universal tendency for decay? A physicist in Britain, J. D. Bernal, tried to balance the books. In 1951, he wrote in recondite terminology: "Life is one member of a class of phenomena which are open or continuous reaction systems able to decrease their internal entropy at the expense of the free energy taken from the environment and subsequently rejected in degraded form." Many other scientists have expressed these words as a mathematical equation. Among the clearest and most readable are the statements in a small book, 'The Thermodynamics of the Steady State,' written by a physical chemist, K. G. Denbigh. They can be restated less rigously but more comprehensibly as follows. By the act of living, an organism continuously creates entropy and there will be an outward flux of entropy across its boundary. You, as you read these words, are creating entropy by consuming oxygen and the fats and sugars stored in your body. As you breathe, you excrete waste products high in entropy into the air, such as carbon dioxide, and your warm body emits to your surroundings infrared radiation high in entropy. If your excretion of entropy is as large or larger than your internal generation of entropy, you will continue to live and remain a miraculous, improbable, but still legal avoidance of the second law of the Universe.

"Excretion of entropy" is just a fancy way of expressing the dirty words excrement and pollution. At the risk of having my membership card of the Friends of the Earth withdrawn, I say that only by pollution do we survive. We animals pollute the air with carbon dioxide, and the vegetation pollutes it with oxygen. The pollution of one is the meat of another."

"... In recent times, some interesting insights have come from the investigations of Ilya Prigogine and his colleagues into the thermodynamics of eddies, vortices, and many other transient systems that are low in entropy. Things like eddies and whirlpools develop spontaneously when there is a sufficient flux of free energy. It was in the nineteenth century that a British physicist, Osborne Reynolds, curious about the conditions that led to turbulence in the flow of fluids, discovered that the onset of eddies in a stream or in a flow of gas takes place only the flow exceeds a critical value. A useful analogy here is that if you blow a flute too gently no sound emerges. But if you blow hard enough, wind eddies form and are made part of the system that makes sound.

Extending the earlier mathematics of the American physical chemist Lars Onsager, Prigogine and his colleagues have applied the thermodynamics of the steady state to develop what might be called the thermodynamics of the "unsteady state." They classify these phenomena by the term "dissapative structures." They have a structure, but not the permanency of solids; they dissapate when the supply of energy is turned off. Living organisms include dissapative structures within them, but the class is broadly based. It includes many manufactured things, such as refrigerators, and natural phenomena such as flames, whirlpools, hurricanes, and peculiar chemical reactions. Living things are so infinitely complex in comparison with the dissipative structures of the fluid state that many feel that, although on the right track, present-day thermodynamics has far to go in defining life. Physicists, chemists, and biologists, although not rejecting these notions, do not make them part of the inspiration of their working lives. Their response is like that of a wealthy congregation to the exhortations of their priest on the virtues of poverty. It is something felt to be good, but not a way of life for the next week.

A crucial insight that comes from Schrödinger's generalization about life is that living systems have boundaries. Living organisms are open systems in the sense that they take and excrete energy and matter. In theory, they are open as far as the bounds of the Universe; but they are also enclosed within a hierarchy of internal boundaries. As we move towards the Earth from space, first we see the atmospheric boundary that encloses Gaia; then the borders of an ecosystem such as the forests; then the skin or bark of living animals and plants; further in are the cell membranes; and finally the nucleus of the cell and its DNA. If life is defined as a self-organizing system characterized by an actively sustained low entropy, then, viewed from outside each of these boundaries, what lies within is alive."

-- Lovelock, James: The Ages of Gaia (1988)


Dissipative structures are doubly dissipative. The structures dissipate heat and they themselves dissipate when the source of external energy is removed.

Question: How can a complex machine maintain its identity in the middle of turmoil?

Answer: By dissipating heat.

"... Self-organizing phenomena provide a useful image for answering this question. After all, the intricate patterns of eddies and vortices characteristic of turbulence must also subsist in the midst of tumult. How can they do it?

The structures generated by turbulent flows are called "dissipative structures" because they use a pattern of eddies inside of eddies to transport energy from higher scales to lower scales, where it can be dissipated as heat. Heat transport, normally considered a source of waste, is made into a source of order: channeling and dissipating energy across a hierarchy of nested eddies can generate complex patterns by amplifying and stabilizing small random fluctuations."

-- De Landa, Manuel: War in the Age of Intelligent Machines (1991) space picture

Please report errors to -->
This page was first created on --> 1/5/98; 12:05:58 CET
This page was last modified on --> 1/5/98; 17:15:51 CET

space picture