The Second Law, Part 2. [11/14/03]
Life and Complexity
Given a broad enough definition of complexity, we can perhaps say that ”there is no Life without complexity” [faulty logic: inferring causality from correlation]. Whether or not this hints at ultimate causality, it provides no clue as to proximate causality, which is the usual concern of science. Identifying proximate causality frequently involves looking for features that are unique to the phenomenon being investigated. In the case of life, complexity is surely not such a feature.
What would such a candidate be? A favorite of complexity theorists (Prigogine, Kauffman) is reproduction The existence of self-replicating autocatalytic polymers naturally incites enthusiasm among advocates of the reproductive imperative (Dawkins) in evolution and biology. However, since the references Prigogine cites on the subject are all more than twenty years old, one wonders how fruitful this approach has been.
A 4th Law perspective suggests a much different candidate. One feature which appears to distinguish life from other “complex” systems is that its various processes are contained within highly impermeable membranes (skins, cell walls). To illustrate the difference in my point of view, picture a pan of water boiling on the stove. If Prigogine were asked what he saw that resembled life, he would most likely pick the convection cells formed by the circulating water. I, on the other hand, would pick the pan.
As far as I know, none of the “self-organized” systems presented as examples of complexity generate membranes. Imagine the excitement if astronomers scanning the cosmos were to discover a galaxy, star cluster, gas cloud, solar system or any other aggregation enclosed, like an amoeba, in a membrane!
I find the statement “The irreversible processes that produce entropy create these organized states.” undeserving of the emphasis Prigogine gives it. Since “irreversible processes that produce entropy” are the only processes that exist in the real world (as Prigogine himself points out), then of course these processes “create organized states”, along with disorganized states and everything else.
It appears to me that the 2nd Law is indifferent as to whether order is created or not. Consider the following example: Suppose we supply the same amount of energy to a bomb, a rocket ship and a robot arm assembling automobiles. For all three processes the energy would be converted to work and waste heat. The bomb would create disorder, the rocket ship would be approximately neutral and the robot would create order. The operation of the 2nd Law (the amount of entropy created) is independent of these outcomes. (As an aside, it is interesting to consider which of the above processes would be most likely to result in “self-organized” structures.)
So if the 2nd Law isn’t up to the job, maybe another law is. Suppose the 2nd Law and 4th Law are logically and phenomenologically orthogonal, like the two faces of Shiva (the destroyer and the creator). They could then be thought to work in tandem, with each serving a different and non-overlapping function. This may be analogous (perhaps strictly) with the orthogonality of the two fundamental forms of energy, potential and kinetic.
This is not to say that the 4th Law is any more biased in the direction of order than the 2nd Law, since order is, once again, not a thermodynamic property. However, the 4th Law is more likely to point to the causal mechanism(s) relevant to the evolution of order.
After writing the above, it occurred to me that it is easy to criticize and that it would be interesting if I could find some support for my membrane theory. So I did a Google search for “membranes and the origin of life”. Lo and Behold! I found the attached article describing recent findings by a research team from (wouldn’t you know it) UC Santa Cruz.
Since I was not previously aware (as far as I can recall) of this or any similar research, I take this as supportive of my 4th Law perspective, since I arrived at my membrane conclusion by reasoning from first principles, as previously discussed.
Upon reading the UCSC article, it might be tempting to ask “Isn’t this just what the complexity guys have been talking about?” My answer would be “No.” The descriptions of complexity which Kauffman, Prigogine, et al have presented revolve around a class of phenomena usually described as “dynamical”, “nonlinear”, “chaotic” or “fractal”. In Part V “Order Through Fluctuations” of his textbook Modern Thermodynamics Prigogine is very specific about the nature of “far-from-equilibrium systems”, which are defined in terms of “bifurcation and symmetry breaking”. None of these descriptions apply to the simple membranes described in the article. Rather, they are notably static (as they would need to be to perform as containers), linear (in the sense that they are additive structures composed of a single type of molecule), predictable (in that the molecular pattern repeats in a regular fashion) and (since the pattern occurs on only one scale) they are clearly not fractal. As an illustration of how different this viewpoint is from that of the complexity theorists, neither “membranes” or “cell membranes” is listed in the index of Kauffman’s Investigations.
According to Dawkins, the cells of a human body contain over 200 acres of membranes, which not only surround cells, but provide substrates for the various chemical “factories” that operate inside the cells. Perhaps primitive membranes provided the templates for the precursors of RNA or DNA.
It is hoped that the above will provide a distraction from the Siren song of the 2nd Law. It is clear that I have only scratched the surface regarding the ramifications of the 4th Law, and much work needs to be done to flesh out its implications. Areas of interest are the possibility of modeling various processes, such as mutating resistor networks, or the design of laboratory or thought experiments to verify or illustrate the operation of the 4th Law.