(Copyright © 2000 Piero Scaruffi | Legal restrictions - Termini d'uso )
Biologist Eric Schneider and Dorion Sagan side with
Ilya Prigogine (and his distinguished predecessors Alfred Lotka and Erwin Schroedinger)
in thinking that biological systems are the product of
non-equilibrium thermodynamics, and indirectly the product of the second law
of thermodynamics (that entropy can never decrease, unless there is a flow
Living systems "emerge", or self-organize, and, de facto, it is
inevitable that they emerged: it is written in the laws of physics.
Non-equilibrium thermodynamics is the science of life.
Thermodynamic equilibrium is death.
Schneider believes that there is more than a mere tendency towards creating life. He believes that life is a way to optimize and accelerate (not just carry out) the production of entropy mandated by the second law of Thermodynamics. Living systems are the most efficient way ever devised by Nature to destroy order; and never mind that living systems themselves appear to be among the most ordered systems ever created. It is all a trick to ultimately destroy order, just like warships are sophisticated complex buildings but overall their contribution to history was to destroy buildings.
In 1965, American physicist Joseph Kestin proved that closed systems who are suddenly "freed" (i.e., their constraints are removed) tend to move towards a new state of equilibrium that is an "attractor". This state is called "attractor" because it does not depend on the order in which the constraints are removed: the system "has" to move towards that state. In other words, not only are some processes irreversible, but processes have a direction and an end. This is expressed by his "Unified Principle of Thermodynamics" (It is called "unified" because it really summarizes the other laws of Thermodynamics).
Schneider believes in a natural extension of this principle: a system pushed away from its attractor, will tend to return to the attractor. The stronger the push, the stronger the reaction, the reaction being some form of self-organization. When the gradient pushing the system is particularly strong, the system may self-organize in ever more complex structures.
Thus Schneider believes that nature will create complex systems whenever it can: it will use any means available to achieve equilibrium.
The "actor" that pushes systems away from equilibrium is a gradient (a difference of temperature, pressure or other). Whenever a gradient is applied, the system is no longer in equilibrium. Schneider believes that the reaction to a gradient is internal reorganization aimed at reducing and eventually neutralizing the external gradient. Gradient neutralization is a fundamental property of Thermodynamics, a fact already proven in 1993 by Don Mikulecky.
"Exergy" is the amount of energy that one can extract from a system in the form of work. When the system has reached a condition of equilibrium, its exergy is zero. Exergy is thus also a measure of how far from equilibrium a system is. (An equivalent way of describing this phenomenon is to talk of "gradients", because the gradient is what can be used to generate work: heat, for example, can be turned into work because there is cold, otherwise it would be useless). temperature, for example, is what Living beings are nonequilibrium systems, so they have high exergy. Schneider believes that the universal tendency towards equilibrium is driving evolution, that Nature is building more and more complex systems in order to erase exergy ever more efficiently. Living beings are only a cog in the machine built by Nature to destroy all exergy and achieve equilibrium. Life is only a way to break down concentrations of energy and turn it into diffuse waste heat. And we are an accidental by-product of such a universal process. Animals, for example, degrade the exergy of plants when they eat them. Furthermore, they do so in a way that is more efficient than other physical processes (burning the plant, for example, would radiate energy, while a cow eating grass radiates very little energy). In a sense, Nature created animals because they are the most efficient way to erase the exergy of plants, and it created plants because they are the most efficient way to erase the exergy of sunlight, and so on. Ecosystems have evolved from systems that emitted a lot of exergy to systems that emit little exergy. Metabolism is simply a way to degrade energy, and today's animals (such as mammals and birds) are a lot more efficient at it than the first forms of life. Evolution has been progressing towards more and more efficient systems to destroy exergy. Genetic information is simply information about how to destroy exergy.
Ecosystems as a whole can also be viewed as efficient destroyers of gradients, destroyers that are built and driven by energy flows. Schneider and Sagan review the classic studies on ecosystems as thermodynamic systems of Evelyn Hutchinson, Spanish biologist Ramon Margalef, Eugene Odum In the new language, ecosystems can be shown to progress towards increased production of entropy and increased reduction of gradient (a different way of saying that biomass, species diversity and energy throughput all increase). The dynamics of ecosystems, in turn, drives evolution. It is the second law that selects the systems that are best at reducing gradients. Natural selection is, in a sense, an afterthought: the most important selection has already occurred, driven by the second law of thermodynamics.
Darwin created a bridge between humans and other forms of life, and explained how one descended from the others. Sagan and Schneider attempt to do something similar for living systems and non-living systems. Non-living complex systems play the same role that living systems play: they are just a bit less efficient. But they too are driven by the same phenomenon (ultimately, a "gradient"). The too spontaneously organize due to the energy flow caused by the gradient. Thus any non-living complex systems appears to be a predecessor of a living system. It is "born" and it "grows" and it "evolves" in a way similar to how life does, except that it is not alive (for example, it does not reproduce).
Schneider summarized his universal principle as "Nature abhors gradients". Whenever there is a gradient, Nature responds by creating the most efficient way to erase it. One such efficient way is life, and us.
In the end, the second law of Thermodynamics turns out to be responsible for both processes of living beings: both their growing and their decaying, both their non-equilibrium (peaking with progress and civilization) and their equilibrium (death).
In the end, the purpose of life turns out to be death: Nature invented life on Earth as the most efficient process to reduces the gradient created by the Sun heating the Earth. The ultimate goal is to reestablish an equilibrium that will, incidentally, destroy all life when life will no longer needed to reduce a gradient that life will have erased. The meaning of life is, ultimately, suicide.
This book is an invaluable compendium of everything that has been written on the subject of thermodynamic study of life over the last century.
TM, ®, Copyright © 2005 Piero Scaruffi