Home
(Illuminati News)

Home
(Spiritual Solutions)

Site Map
(Illuminati News)

Site Map
(Spiritual Solutions)

News & Updates
(Spiritual Solutions)


Articles by Wes Penre

Articles on Spirituality

Links

Copyright Fair Use

Disclaimer

E-Books

Website on DVD

About Me

Site Search

E-Mail Me

 


Worlds Within Worlds - The Holarchy of Life (Chapter 10)
by Andrew P. Smith, Oct 24, 2005
(Posted here: Sunday, May 27, 2007)


10. SELECTION WITH DIRECTION

"In sufficiently complex systems, selection cannot avoid the order exhibited by most members of the ensemble. Therefore, such order is present not because of evolution but despite it."

-Darcy Thompson1

 

"I believe...that the [theory of evolution] will hereafter be shown to be a part, or consequence, of some [more] general law."

-Charles Darwin2

 

As I pointed out earlier, Darwinism has long had an army of critics, a cottage industry that thrives on pointing out the weaknesses or perceived weaknesses of this theory. Most of their criticisms boil down to one major complaint: Darwinism can't account for major evolutionary changes. It's one thing to understand how new species of organisms evolve, another to explain the emergence of major new adapations, such as the eye or the cerebral cortex. It's even more difficult to understand the major transitions that must have occurred when the first cells emerged, or the first organisms emerged.

In the previous chapter I argued that a broader version of Darwinism can be understood to operate throughout the holarchy, on every level and perhaps every stage of existence. A significant weakness of Darwinism in any form, however, is that it requires a long chain of events, each of which is of very low probability. The probability that a particular gene will mutate during a reproductive cycle is perhaps less than one in one hundred thousand (Lewin 1997). Other forms of random variation that I considered are also fairly rare.

Thus it is that almost all the alternative theories to Darwinism that have been proposed make it their central goal to demonstrate that evolution could occur quite rapidly. If life had to proceed by trial and error, the argument goes, it never would have gotten anywhere. There must be a means by which holons can jump, rather than crawl (in fits and starts), up the scale of existence.

Theories of this kind are usually referred to as theories of complexity or self-organization. Neither of these terms is very precise. As I pointed out in Chapter 3, we don't really have a good definition of complexity. Self-organization, on the other hand, is a very badly overworked term, used so often in discussions of evolution that it threatens to become meaningless. As I will use these terms here, they simply mean that certain holons have the ability to assemble into higher-order holons spontaneously. Rather than associating with one another randomly, with certain combinations exhibiting new properties that enhance the survival of themselves or their individual components, holons may home in, so to speak, on the right combination immediately. It should be obvious that if large, rapid changes of this kind are indeed possible, many transformative and perhaps transcendent phases in evolution become much more understandable.

Many kinds of self-organizing processes have been proposed, and most of them are supported by considerable evidence. Evidence, that is, which demonstrates that the processes postulated by the theory do exist, and conceivably could account for some kinds of evolutionary change. It does bear repeating, though, that it's virtually impossible to prove that any particular process did account for any evolutionary development. This is every bit as true for the alternatives to Darwinism as it is for Darwinism itself. Indeed, in some respects it's even more of a problem for the alternative theories, because almost by definition, they tend to be most concerned with evolutionary transitions for which there is no fossil evidence.

In this chapter, I will examine a few of these theories of self-organization. I will not attempt to discuss all of them, nor will I discuss any of them in great detail, as other sources of such discussion are available (Gleick 1988; Casti 1992; Kauffman 1993; Prigogine and Stengers 1994; Capra 1996). Rather, I will focus on a few of these theories that I feel offer a representative view of the entire field, and highlight their key strengths as well as limitations. I will be asking to what extent such processes may be able to "fill in" our picture of evolution where Darwinism seems inadequate, as well which evolutionary processes they seem unable to account for. Following this discussion, I will then consider the prospects for a broader understanding in which self-organizing processes are combined with evolution by random variation and natural selection.

 

Dissipative Structures

The theory of dissipative structures was formulated several decades ago by Ilya Prigigone, who later received a Nobel Prize for this work. Prigigone was a pioneer in the study of nonlinear dynamics, which applies to chemical reactions far from equilibrium. Every chemical reaction has an equilibrium, in which there is no longer any net change in the reacting species; and any reaction, left to itself, will reach this state. For example, if compound A is converted to compound B, this conversion will proceed until the concentrations of each compound reach a certain proportion to each other. At this point, no further net conversion of A will occur unless the reaction is perturbed--by adding more A, for example, or by removing some B. At the equilibrium state, the reaction is still proceeding, but the rate of conversion of A to B is equal to the rate of conversion of B to A.

Before this century, little was known about the properties of chemical reactions not at equilibrium, because this was viewed as a somewhat unnatural state. In order to maintain a reaction far from equilibrium, as I just noted, it has to be perturbed in some manner. However, it turns out that under these conditions, some chemical reactions have very unusual properties. The concentrations of the reacting species can undergo random, minor fluctuations. Sometimes, one of these fluctuations will become ampified, resulting in a major change in the relationships of the different chemical reactants to each other (Prigogine and Stengers 1984).

Initial evidence for the theory came largely from certain chemical reactions in which the reacting substances organize into highly ordered phases, in apparent contradiction of the law of diffusion (Zhabotinski 1964). These phases are often observed by using chemicals that have different colors. As anyone who has ever mixed two or more colors of paint together knows, they tend to form a single color, in which the several original colors are irrevocably blended. In dissipative reactions, however, the different colored chemicals separate into highly ordered phases, such as rings and spirals. The molecular components of the reaction have organized themselves into something very new and different.

These phases are considered by Prigogine to be "higher" or more complex forms of existence than the original mixture, because they require energy to form and maintain, some of which energy they "dissipate" into the environment. That is, the reaction imports or absorbs energy from the medium which goes into the creation of the ordered shapes seen in the solution. This process is somewhat reminiscent of living things. Cells and organisms maintain their complex form by assimilating forms of energy, such as nutrients or sunlight, and releasing some of it back to the environment in the form of heat, gasses or undigested food.

That dissipative structures exist is not in question. The issue is whether, or to what extent, this kind of process could account for major evolutionary changes. Given that most of the evidence for dissipative structures comes from studies of chemical reactions, they are most naturally candidates for explaining some of the events occurring in the emergence of cells, which we have seen required assemby of complex molecular structures. Indeed, some recent studies have reported that certain components of cells, including calcium ions (Somogyi and Stucki 1991), ion channels (Svatchencko and Korogod 1997), and microtubules (Chou et al. 1994), can form dissipative structures.

However, it's one thing to demonstrate that certain components of fully-evolved cells can form dissipative structures. It's quite another to establish that the same or similar processes could have given rise to the first cells. What these recent studies suggest--assuming that they can be replicated, for in science it's often fairly easy to fit a currently popular theory to observations--is that the ability to form dissipative structures may have been a feature of existence that evolved, rather than itself being a driving force of evolution. This is a critical distinction, which, as I shall discuss later, may shape our views about just how self-organizing processes could be related to other evolutionary processes, such as Darwinism.

A second weakness of dissipative structures as an evolutionary theory--a problem, we will see, that it shares with most other self-organizing theories--is that it they can't account for the critical step of information coding. Evolution of the cell, as I emphasized in Chapter 8, requires more than the assembly of enzymes and other types of biomolecules. It also requires creation of an informational holon--the genome--which allows this assembly to be reproduced. So even if some components of a cell could emerge through dissipative processes, these components could not propogate themselves without additional major evolutionary changes.

In summary, while dissipative processes might have contributed to the evolution of some stages within the cell, there is still no compelling evidence that they were a major factor in evolution at this level. And while there has been speculation that such processes may also operate at higher levels of existence--in human mental processes (Mandell and Selz 1995; Sel 1997), in human social organizations (Duong and Reilly 1995), and even in consciousness (Schorr and Schroeder 1989)--the evidence for them there is even less convincing3. A key problem, as I alluded to earlier, is that when a self-organizing theory becomes popular--and probably more than a dozen such theories have been proposed in the past fifteen years or so--there is a fairly intensive effort by some individuals to apply it to a very wide range of phenomena. The fact that some of these phenomena have some characteristics that are superficially similar to those of dissipative processes doesn't prove that these processes actually create or explain these phenomena. Even less does it prove that these phenomena originally evolved through dissipative processes. What one not unsympathetic critic of chaos pointed out could probably apply to other complexity theories as well: "One identifies chaos in models that are fitted to data, not in the data themselves."4

 

Cellular Automata

As I discussed in Chapter 3, cellular automata were invented by the computer scientist John van Neumann almost half a century ago, as a means of designing a computer that could reproduce itself. The exercise led him to the important insight that reproduction requires a means of both transcription, or copying, a program, as well as translation, or running the program. This dual nature of reproduction was later found to exist in cells as well.

However, the cellular automata that are the subject of so much current interest as a model of self-organization are a little different from van Neumann's original version. They are not real, reproducing computers, but rather simple points, or little squares, on a two-dimensional grid. This grid is visualized on a computer screen, and a program is written that provides certain rules governing when and how these little squares or automata will reproduce themselves. For example, one rule might say that a square will reproduce when it's in contact with two neighboring squares. Another rule might specify reproduction when it is separated by a certain distance from another square. When the program is allowed to run, some of the squares reproduce, resulting in new relationships among the automata. These new relationships, in turn, result in a new round of reproduction. As the program is run through a great many steps, the squares multiply, and populate various positions on the grid (Casti 1992; Wolfram 1999).

Depending on the nature of the rules governing reproduction of cellular automata, very elaborate patterns can be formed on the grid. In some programs, the patterns generated bear a startling resemblance to the forms of certain organisms. Indeed, an early program of this type designed by mathematician J.H. Conway and simply called Life, was capable of generating a great variety of "organisms" in this manner (Casti 1992).

Such success has naturally led some theorists to suggest that the body types of many organisms may have evolved from this kind of self-organizing process. Indeed, a great many patterns in nature, of non-living as well as non-living things, can be duplicated with programs that generate form from some relatively simple mathematical equations (Ball 1999). Yet because they are usually are run on two-dimensional computer screens (though they can be created in three or any number of higher dimensions), cellular automata generally provide no more than what are literally just superficial or surface features of life. Biochemist Michael Behe, whom we saw earlier believes that cells must have been the creation of an intelligent designer, captures this point elegantly:

 

"Some proponents see great significance in the fact that they can write short computer programs which display images on the screen that resemble biological objects such as a clam shell. The implication is that it doesn't take much to make a clam. But a biologist or a biochemist would want to know, if you opened the computer clam, would you see a pearl inside? If you enlarged the image sufficiently, would you see cilia and ribosomes and mitochondria and intracellular transport systems and all the other systems that real, live organisms need?"5

 

Nor is Behe's view prejudiced by his creationist leanings. Computer scientist Steven Pinker, a fervent supporter of Darwinism, makes much the same point:

 

"The 'complexity' that so impresses biologists is not just any old order or stability. Organisms are not just cohesive blobs or pretty spirals or orderly grids. They are machines, and their complexity is functional, adaptive design; complexity in the service of accomplishing some interesting outcome. The digestive tract is not just patterned; it is patterned as a factory line for extracting nutrients from ingested tissues."6

 

While this is a valid criticism of much of what many complexity theories have produced so far, it should be pointed out that the holarchical worldview does provide a potential opening for a rebuttal. Both Behe and Pinker are arguing that the detailed microstructure of tissues is not addressed by large-scale patterns. But one could just as well apply cellular automata, or other complexity theories, to the lower levels and stages of existence; perhaps there are "pretty spirals" or "orderly grids" in the molecular and cellular structures as well. In any case, more recent work with cellular automata is attempting to address this criticism. Several studies have claimed that cellular automata can model a wide range of phenomena in living systems, including the catalysis of enzymes (Kier et al. 1996), assembly of bacterial membranes (Lahoz-Beltra 1997), formation of tissues (Lee et al. 1995; Markus et al. 1999), the beating of the heart (Siregan et al. 1996), and the spread of populations of organisms (Karafyllilis 1998).

An additional problem with cellular automata as an evolutionary theory, however, which these studies don't address, is that for the patterns to be formed, a certain amount of information has to be inputted into the system, in the form of the rules specifying when they will reproduce themselves. The automata themselves can't create these rules; they merely follow them. So by themselves, cellular automata would seem incapable of giving rise to complex living forms. However, again, this does raise the possibility that they might operate in some combination with Dawinian processes of the kind I discussed in the previous chapter. I will return to this point later.

This brings us to the most significant limitation of cellular automata as a model of evolution. As with dissipative structures, cellular automata don't provide an obvious means by which the forms generated can be coded into the information of the genome. While many of the large-scale patterns formed by cellular automata can themselves reproduce in toto following certain programs, this kind of reproduction clearly is not the kind used by living things, as originally divined by van Neumann. Real cells and organisms reproduce themselves on the basis of information they contain within themselves. As complexity theorist John Casti acknowledges:

 

"Any genuinely self-reproducing configuration must have its reproduction actively directed by the configuration itself...Thus we require that responsibility for reproduction reside primarily with the parent structure."7

 

In fact, cellular automata might be better applied to our understanding of development rather than evolution--that is, the process by which a new organism is created from a single fertilized cell. It's well recognized that much of development depends on epigenetic or contingent processes. That is, while the genome specifies certain cell types, the latter arrange themselves into tissues and organs in part according to their relationships with other cells. This kind of process, in which at least some of the information or rules are already in the reproducing system, appears to offer a much closer analogy to cellular automata.

 

Autocatalysis

The theory of autocatalysis, originally formulated by chemist Manfred Eigen (1971), has been more recently developed by Stuart Kauffman of the Santa Fe Institute, a hotbed of complexity theorists. Kauffman believes that Darwinism, at the very least, is incomplete, and has spent most of his career trying to show, mathematically, how complex forms of life could evolve relatively quickly from simpler forms. His major book, The Origins of Order (1993), is surely one of the more impressive scientific treatises published in the past decade (for a briefer and more accessible account of his major ideas, see his At Home in the Universe, 1995). In addition to autocatalysis, Kauffman has worked out the theoretical basis of many other types of self-organizing processes which are beyond the scope of this chapter to consider. Regardless of how correct he proves to be in arguing that such processes are at the heart of evolutionary change, he raises a number of vital issues, and provides one of the most penetrating critiques I have seen of not just Darwinism, but also of the views of its other challengers.

In a sense, Kauffman's approach is a blend of that used by those developing theories based on cellular automata and dissipative structures. Like the former, most of Kauffman's evidence comes from computer simulations, which he uses to track the consequences of beginning with a few simple holons and a few simple rules governing the way they interact. Like dissipative structures, on the other hand, autocatalysis is a theory largely about molecular processes, and is thus most directly applicable to an understanding of early events in the evolution of cells.

Kauffman begins by postulating a simple chemical reaction, in which one kind of molecule, A, is converted into a second kind, B. This reaction is catalyzed by a specific molecule. Later, a second chemical reaction emerges, catalyzed by a second molecule, in which B is converted into C. Still later, further chemical reactions evolve. Eventually, a chain of chemical reactions is formed, in which substance A is converted, through many steps, to a large number of other substances.

Such a chain, by itself, is a fairly simple and unremarkable form of existence. What introduces complexity into the system is the concept of autocatalysis. On the basis of certain assumptions about enzyme catalysis, Kauffman proposes that when a large enough number of reactions have evolved, the probability is quite high that the products of some reactions will serve as catalysts for other reactions. For example, product M formed from L may catalyze the formation of C from B. Product R may catalyze the formation of I. And so on. Thus feedback loops form, in which the reactions are producing substances that enhance their own ability to produce more of these substances. As a result, the entire system reaches a point when it becomes a self-sustaining network of chemical reactions. Given a supply of energy, which any living thing needs, it can maintain the network indefinitely.

Kauffman's autocatalytic scheme, while not supported by any direct laboratory evidence, is nevertheless highly plausible in some respects. Most evolutionists believe that life on earth originated in a primordial "soup", pools of water in which small molecules were formed and began interacting with each other. At least some of Kauffman's starting assumptions are sufficiently general, and sufficiently based on what we know about the behavior of chemical reactions, that we could reasonably assume them to portray primordial conditions fairly accurately. And while autocatalysis began as a theory of self-organization of chemical reactions, it may be generalizable to many other types of phenomena.

Nevertheless, autocatalysis as a model of cell evolution has a glaring weakness. The network of chemical reactions it produces, while superficially similar to those inside a cell, is different in two key respects. First, in a cell, catalysts--that is, enzymes--are not synthesized in ordinary metabolic reactions. They are synthesized from DNA and RNA, in a special process distinct, physically as well as functionally, from the synthesis of all other kinds of molecules. While enzymes might conceivably have initially been synthesized as in Kauffman's scenario, at some point in evolution there would have had to be a major shift to the modern process.

Furthermore, even if an autocatalytic network were provided with an informational holon to enable itself to reproduce, it still would be a questionable model of a cell. This brings us to the second way in which autocatalytic networks differ from real networks in the cell. Metabolic pathways in the cell don't feed back on each other in the way they do in Kauffman's scheme. Products of one reaction may be used by some other reaction, but they are not catalysts of other reactions. So real metabolic networks in the cell are not autocatalytic. If autocatalysis were an evolutionary mechanism, it would have to be one that was later greatly modified.

Kauffman is not unaware of these problems, and attempts to address them. He suggests, for example, that autocatalytic networks might originally have contained both nucleic acids--such as the catalytic RNA molecules or ribozymes I discussed in Chapter 8--as well as proteins. Thus information coding might have been part of the network from an early time. However, it's still quite a jump from such networks to the organization of modern cells. One of these gaps that Kauffman's scheme doesn't address is how the process of autocatalysis is actually to be realized in physical, three-dimensional space. In order for reactions to interact with one another in the cell as they do in Kauffman's scheme, they have to be organized very precisely in space. A reaction that produces something used by another reaction has to be located in the cell in such a way that it's product can actually be made available where it's needed. Kauffman's two dimensional diagrams, which simply use arrows to indicate the path by which the product of one reaction is introduced to another, hide an enormous amount of evolutionary headaches.

Finally, some of Kauffman's starting assumptions are questionable. Enzymes can catalyze reactions that go in either direction--that is, if an enzyme can convert substance A to substance B, then in principle it can also convert substance B to substance A. Which direction the reaction goes depends on the relative concentrations of A and B. Much of Kauffman's argument is based on the assumption that primordial conditions would enable reactions to go in either direction, and that the evolving network could take advantage of both possibilities. This is certainly debateable.

Kauffman also doesn't take into account that in a large pool of substances, many chemicals would not be catalysts of the formation of others, but rather inhibitors. That is, instead of specifically promoting certain reactions, they would block them. It's well known that a substrate for an enzyme, if altered slightly in structure, may inhibit that enzyme (Stryer 1988; Creighton 1993). So the laws of probability that Kauffman bases his argument on suggest that it is at least as likely for a substance to prevent the formation of another substance as it is to enhance it. While Kauffman incorporates inhibitors in some of his schemes, he doesn't seem to realize that their existence might very well prevent these schemes from getting off the ground in the first place.

In summary, autocatalysis, like dissipative structures and cellular automata, does not provide an entirely convincing explanation of how real cells could have evolved with the ability to reproduce themselves. Because Kauffman, like other complexity theorists, works largely with computers, he has been accused of practicing "fact-free science."8 I think this criticism is a little unfair. His work is informed by a detailed understanding of the relevant scientific literature, and he has proposed some experimental tests of some of his models. While he has not illuminated all the steps in the evolution of the cell, we must remember that this problem has stumped the best scientific minds of our century. At the very least, Kauffman's work has focussed science more clearly on the steps that have to be understood. Moreover, some of the principles he has elucidated may be fundamental to our understanding of evolution at all levels of existence. For example, the process of autocatalysis suggests that cell-like structures emerge when a certain number of reactions exist. This kind of number could be a fundamental property of holarchical organization, determining the size of not only cells, but of higher level fundamental holons.

 

Non-random mutations

Before proceeding to a general critique of self-organizing phenomena, I want to discuss one other evolutionary process which, though it technically does not belong to this class, likewise raises the possibility of a much faster rate of evolutionary change. This is evolution by non-random mutations, also known as directed or non-adaptive mutations. The history of this idea actually begins nearly half a century prior to publication of The Origin of Species, when Jean Baptiste Lamarck developed a theory based on the inheritance of acquired characteristics. Lamarck believed that variation, rather than being random, might be directly related to the needs and behavior of the organism. For example, if an animal stretched its neck to reach leaves on a tall tree, its progeny would have longer necks. They would stretch their necks still further, passing this gain on to their offspring--and so, Lamarck proposed, giraffes evolved.

In the late 19th century, however, August Weismann argued that since the gametes, or germ cells, of an organism were separate from the other, somatic cells, there was no way that acquired changes in the organism's body structure or physiology could be inherited (Maynard Smith 1997). Strengthening our muscles, for example, may change our muscle cells, but these cells are not the ones passed on to our progeny. Weissmann's doctrine, as it came to be called, was confirmed with the discovery of genes and mutations, which made it clear that Darwinian variation was indeed confined to germ cells under ordinary circumstances.

The possibility of inheritance of acquired characteristics was made even more unlikely following the great triumphs of biochemistry in the middle of the twentieth century. At this time, scientists demonstrated that genes are translated into phenotype through the synthesis of RNA and proteins, an understanding that has come to be known as the central dogma of molecular biology. Since the reverse of this process does not occur--that is, proteins can't direct the synthesis of DNA--it appears that information in the developing organism flows in one direction, from the genome to the phenotype. So even if an organism could somehow change the biochemical makeup of its reproductive cells, this change could not be transmitted to its genes.

Recently, however, this view has been challenged by several researchers studying bacteria. Because of their rapid rate of reproduction, bacteria are in many ways an ideal system in which to study evolutionary processes. Many generations of bacteria can be produced in a matter of hours, days or weeks, making it possible to follow the process of mutation and selection over a reasonable length of time.

When bacteria are grown in culture medium containing certain nutrients, mutations may arise that permit them to use these nutrients. For example, bacteria require an enzyme in order to metabolize the sugar lactose. When bacteria lacking this enzyme (due to a mutation in the gene for this enzyme) are grown in lactose-containing medium, most of them die. A few, however, arise bearing a mutation that, in effect, corrects the earlier mutation, enabling them to synthesize lactose. These bacteria survive, and propagate themselves.

This result, by itself, is quite consistent with Darwinism. It's assumed that the new mutation arises randomly, and is then selected by virtue of its allowing the bacteria possessing it to survive. Experiments by John Cairns and later Barry Hall, however, have suggested that such mutations may not always arise randomly. They may be adaptive or directed; that is, the presence of the sugar in the medium may trigger a process that results in the mutation of the precise gene needed to permit metabolism of the sugar. Several possible genetic processes have been hypothesized to account for this remarkable finding, which has also been reported in yeast, a eukaryotic cell (Cairns et al. 1988; Cairns 1993; Hall 1997, 1998).

These studies are very controversial. Many scientists believe they can be explained in traditional Darwinian terms, without invoking a directed mutation process. Nevertheless, the possibility that some mutations are not entirely random should be taken seriously. It's well-appreciated now that the genome is regulated by a complex web of other molecules, which can selectively turn on or off the synthesis of specific genes. Most of these regulatory molecules are proteins, so clearly information can flow back to the genome in an important sense. These regulatory molecules are not known to cause genuine mutations in genes, but they can affect the structure of genes in certain ways that are heritable.

Another way in which non-random, though probably not adaptive, mutation could occur is suggested by the fact that the genome is not a perfect linear sequence of genes, but a complex conformation of tightly associated DNA and protein (Lewin 1997). Thus some genes might be preferentially exposed to ionizing radiation, chemical carcinogens, or other mutagenic agents. Studies of certain diseases that result from mutations, such as colon cancer, have shown that particular regions of the mutated genome, known as "hotspots" are much more likely to be mutated than other regions (Miyoshi et al. 1992).

Directed mutations have not been reported in multicellular organisms, and even if they were to be discovered there, Weissmann's doctrine cautions us against thinking the basis for Larmarckian inheritance would be completely in place. Biologist Ted Steele, however, believes that some aspects of the immune system could be inherited in a directed manner. That is, an organism that developed antibodies to a particular foreign agent could pass the gene responsible for its altered immunity into its germ cells (Steele et al. 1998). But even if Lamarckian inheritance is never established, non-random mutations could still play a critical role in evolution, providing for a much faster process of change than random mutations, which are of very low probability. A perennial criticism of Darwinism is that significant evolutionary change requires not just one but a whole sequence of mutations, the cumulative probability of which would be vanishingly small. Yet Hall has found double mutants in his bacteria that appear as frequently as single mutations under ordinary conditions.

 

Self-organizing Processes: A Critical Evaluation

This brief discussion of a few types of self-organizing processes has barely scratched the surface of a very complex and controversial area. Nevertheless, on the basis of this discussion, I will try to summarize what I see as the strengths and the limitations of evolutionary theories based on these processes. The best known strength of these theories, of course, is that they offer a means by which evolution can proceed much more rapidly than by Darwinian processes. The kinds of patterns created by dissipative structures or cellular automata would be vanishingly improbable if they had to be built up by a random process, one small step at a time. These processes seem to enable life to skip a huge number of these steps, leaping from one kind of organization to another very different kind.

This is an important strength not only because of the greater speed of evolution possible, but also because it may help the process avoid blind alleys. In Darwinian evolution, each step or variation must have some selective value on its own, in order to survive for the next round of variation. If it takes one hundred independent mutations for one new adaptation to emerge from another, and every one of these mutations does not increase adaptive value, the process may get stuck along the way. As I discussed in Chapter 7, some critics of Darwinism believe that the eye would have met this fate. If it had evolved simply through random variation and natural selection, it would have soon reached a point where no single further mutation could increase its adaptive value. Though in principle it could evolve into a much more adapted structure, it could not get past this botteneck by a one step at a time process.

Self-organizing processes, by virtue of being able to skip steps, seem to offer a way around this problem. Suppose, for example, that one mutation perturbed the development of the eye in such a way that it underwent a major organizational change in its structure. The difference between this organization and the previous one might bypass many individual stages which would not be selectively advantageous on their own.

The reader will note that in this discussion I have assumed that self-organizing processes can be subjected to natural selection, just as Darwinian ones are. They aren't necessarily so, however, which is another potential strength of evolutionary theories based on them. Self-organizing processes may sometimes be capable of occurring and becoming established without competition or selection. This happens when the new form of organization is the only one possible. Kauffman's autocatalytic networks, for example, seem to represent an inevitable outcome of certain associations of chemical reactions. When the number of these reactions reaches a certain size, the laws of probability dictate that autocatalysis will become a significant factor. As a result, the reactions become intricately interconnected with one another, and begin to function as a unit. To the extent that this change truly is inevitable, the network does not compete with the individual chemical reactions that gave rise to it. The latter simply disappear as independent processes.

The ability of a process to evade selection can also greatly enhance its rate of evolution. In Darwinian evolution, even after a new variant appears through a random, highly improbable variation, it may take a long time to become established through selection. This would be equally true even if the mutation arose through a directed process. If the adaptive value of the new variant is only slightly greater than that of what preceded it, many generations of individuals may be required for the new variant to establish itself. Furthermore, unless individuals with the new variation become separated as a population from the original type of organism, there can be no speciation process, in which the individuals in each population continue to evolve in different directions.

All these problems can be avoided, in principle, by a self-organizing process in which a new form of existence emerges in a single, statistically highly probable step. Not only is the emergence of the variant ensured, but so its establishment as a dominant form of existence. Moreover, because it is so different from what appeared before it, there may be no speciation problem. A large change of this type, if it were adaptive, could possibly create a new species in a single step.

Finally, perhaps the most important strength of self-organizing processes--though many of the theorists who have described them would not themselves see them this way--is their potential to complement Darwinian processes. It's not really necessary to make an either-or choice between one type of evolutionary theory or the other. It isn't just that one type of theory may offer a better explanation of some processes, while another theory is more suited for other processes. Some processes may best be explained by invoking some combination of these two very different kinds of evolutionary theories. I will develop this idea a little further in the final section of this chapter.

These, I believe, are the main strengths of self-organizing theories of evolution. On the other hand, these theories also have several major weaknesses, some of which I have touched upon earlier. First, there is a lack of direct evidence for these theories. By this I don't simply mean that no one has shown that evolution actually occurred through self-organizing processes. This criticism would be just as applicable to Darwinism. I mean that in many cases, these theories have not been shown to account for the kinds of processes that evolution required. Thus dissipative structures and cellular automata--perhaps--can fairly accurately model a few processes occurring in evolved cells or organisms; it's not clear that they can offer an explanation of how these processes originally evolved. Likewise, autocatalysis can, in theory, account for the emergence of metabolic networks in which enzymes are synthesized by classic chemical reactions. However, enzymes are not actually synthesized in this manner in the cell. Directed mutations have not yet been reported in multicellular organisms, though perhaps they could have played a role in the evolution of cells.

A second limitation of theories of self-organization is that they don't adddress the fundamental question of how information storage evolved. It's not sufficient to show that a complex cell-like structure could have emerged from certain self-organizing processes. A theory must also provide a means by which the information representing this structure could have been incorporated into the genome, allowing the cell to reproduce itself. All pure self-organizing theories described so far, to my knowledge, fail this test.

A third limitation of self-organizing theories is that they depend on certain defined conditions or properties of the evolving entities. Cellular automata require certain rules in order to generate their patterns. Autocatalysis takes the existence of catalytic enzyme molecules as a given. Some other self-organizing theories, such as chaos (Gleick 1988), catastrophe theory (Thom 1989) and criticality (Bak 1996), are even more sensitive to starting conditions. In other words, these theories attempt to explain how evolution occurred from a certain point on, while ignoring how it got to this point in the first place. This criticism doesn't invalidate their explanations as far as they go, but it does suggest that these theories could not function as a broad description applicable to many events.

Still another significant weakness of many self-organizing theories, rarely addressed, is that they seem incompatible with a deeper view of holarchy. As I demonstrated in the first part of this book, there are numerous analogies between different levels of existence. Life seems to be based on certain fundamental themes that repeat themselves again and again throughout the holarchy. Though most complexity theorists accept some kind of holarchical view, they don't seem to realize that the existence of such regularities is not easy to reconcile with the indeterminacy and creativity at the heart of many of their theories. This is particularly true of dissipative structures, for example, as well as of several theories not discussed here, such as chaos, catastrophe and criticality. These theories--even more than Darwinism, which is constrained by natural selection--emphasize that major evolutionary changes are unpredictable, that we can never really know where the process is going. While there surely seems to be some unpredictability in the details of evolution, nonetheless the principles of holarchy suggest a very profound and understandable order in its major features. Theories which bandy about words like "creative" and "spontaneous", it seems to me, have problems accounting for this order.

To be fair, there is a long tradition of scientists who understand self-organization as a process of putting together existence in a fairly deterministic and predictable fashion (Thompson 1992; Lima-de-Faria 1988; Ball 1999), and as such, they offer a helpful counterpoint to the more popular view of self-organization as unpredictable. Yet these theories have their own problems. They usually postulate, for example, that much of the potential of higher forms of life was present in the very lowest forms of matter, so that evolution was highly constrained at the outset. But such simple physical constraints become to a large extent meaningless at higher levels of existence. Our own properties may be constrained by the fact that we are composed of atoms, but within these limits alone, endless possibilities of organization seem to be possible.

Finally, we might justifiably criticize self-organizing theories, ironically, on the grounds that the changes they propose are too large, too sudden. A perennial criticism of Darwinism is that it takes too long, that there simply hasn't been enough time for the forms of life we see today to have evolved through random variation and natural selection. This criticism, however, can be turned around and applied to theories of self-organization. If major evolutionary transitions could have occurred very rapidly, why has evolution taken as long as it has? If, for example, processes such as autocatalysis and dissipative structures enabled many of the components of early cells to emerge quickly, why did it take billions of years for cells to evolve? If cellular automata are a valid model of the formation of organisms from cells, why did this evolutionary process take an additional several hundred million years?

Nor is the great length of time the only problem. The abruptness of self-organizing phenomena means that their effects will frequently be disruptive, rather than creative. As all molecular biologists are acutely aware, the more complex life is, the less tolerance it has for large changes. Any new mutation, Jacques Monod argued, must pass a number of screens, and most of them never get past the first one--successful integration with the rest of the cell (Monod 1971). A self-organizing process, Behe notes, has even less chance in this regard:

 

"The essence of all life is regulation: The cell controls how much and what kinds of chemicals it makes; when it loses control, it dies. A controlled cell environment does not permit the serendipitous interactions between chemicals [that a self-organizing process] needs. Because a viable cell keeps it chemicals on a short leash, it would tend to prevent new, complex metabolic pathways from organizing by chance."9

 

This last point, it seems to me, is a very strong one in favor of Darwinism (though Behe himself doesn't see it that way), in its broader form, or of a directed mutation process. While conceding that some evolutionary changes are not easily explainable through random variation and natural selection operating over any length of time, and while conceding the possibility of very new and sudden transitions in evolution, the preponderance of evidence suggests that it evolution is for the most part an exceedingly slow process. Darwinism, more than any other evolutionary theory, makes sense of this.

 

Relationship of Self-Organizing Processes to Darwinian Processes

In summary, I believe that while self-organizing theories can make a significant contribution to our understanding of evolution, none of them is very likely to serve as a general theory of the process. Perhaps they would have more explanatory value, however, if they were applied in combination with other theories, particularly Darwinism. I pointed out earlier that some self-organizing processes seem to emerge inevitably, and therefore might not be subject to selection in the usual sense. Yet many self-organizing processes can be subjected to natural selection, at least in principle, so this opens the door to some kind of synthesis of the two approaches. "It is not that Darwin is wrong," Stuart Kauffman concedes, "but that he got hold of only part of the truth...we must understand how such self-ordered properties permit, enable and limit the efficacy of natural selection."10

In a long and detailed discussion of this prospect, Depew and Weber (1997) actually suggest six different types of relationships that these two kinds of evolutionary theories could have. These relationships, each of which has some adherents, include: 1) self-organization is auxiliary to natural selection; 2) self-organization constrains natural selection; 3) natural selection constrains self-organization; 4) natural selection generates self-organization; 5) natural selection instantiates (that is, is a special case of) self-organization; and 6) natural selection and self-organization are part of the same process. These relationships are not necessarily mutually exclusive; one type of relationship could operate during certain phases or stages of evolution, another at some other point.

To get a feel for how Darwinian and self-organizing processes might interact, let's consider a few hypothetical examples. A simple, yet illustrative example of relationship no. 2--self-organization constrains natural selection--is provided by the evolution of cells. All cells make use of molecules such as carbon dioxide and water. These very simple molecules can be said to have evolved by a kind of self-organizing process; when carbon or hydrogen is mixed with oxygen under certain circumstances, these molecules form. Because these molecules existed on earth, life had to evolve in such a way that it made use of them. Thus carbon dioxide and water are components of all cells, and furthermore, all the more complex molecules of cells are synthesized by processes involving these molecules. This, then, is an example of how self-organization constrains natural selection; it provides certain starting conditions within which the process has to operate. This is a trivial example, one that every evolutionary biologist accepts, but nonetheless illustrative of the principle.

Now consider the opposite relationship (no. 3): natural selection constrains self-organization. In the earlier discussion of autocatalysis, I pointed out that such networks might emerge spontaneously, and not be subjected to either competition or selection in relation to individual chemical reactions. However, one could imagine a situation where selection did come into play. For example, suppose several different kinds of autocatalytic networks emerged, all in the same primitive pool. Under these circumstances they might compete for limited energy resources. The most efficient network would be the more likely one to survive. In this manner, natural selection would constrain self-organization.

I have also alluded to earlier a situation illustrating relationship no. 4, where natural selection generates self-organization. In the discussion of both dissipative structures and cellular automata, we saw how some recent studies suggested that these processes might account for certain features in living cells and organisms. We could therefore postulate that organisms with these processes had some adaptive advantage, which allowed these processes to be selected. That is, certain kinds of proteins would result from random mutations. These proteins, by being able to participate in self-organizing processes, would provide the organism with a selective advantage. In this way, the dissipative process would become established in the organism.

One can further imagine scenarios where more than one type of relationship is occuring, and where not only selection, but random variation is also thrown into the mix. In the previous chapter, I discussed how a Darwinian analog might contribute to the evolution of early multicellular organisms, or of higher multicellular stages of organisms. Based on analogies with cultural evolution on our own level of existence, I hypothesized that this began with a change in the genetic surface structure of a cell. It expresses a gene it formerly did not express, or perhaps a different amount of a gene it did express. As a result of this changed expression pattern, the cell's interaction with another cell or cells is altered. This new interaction, in turn, induces the other cell to change its pattern of expression so that it matches that of the original cell. This cell, too, can now transmit its new expression pattern to other cells. As a result, a large number of cells now exhibit an altered expression pattern, and a significant change in the way they associate is possible.

When we combine this idea with cellular automata, we have a powerful way of generating variety in tissue organization. For example, suppose the transmission of genetic surface structure results not from any simple cell-cell interaction, but only from interaction with cells that bear a particular spatial relationship to the first cell. That is, cells transfer this surface structure not to all the other cells in which they are in contact, but only to certain ones. Suppose, furthermore, that the change in surface structure--the expression of a new protein--is also accompanied by reproduction of the cell expressing the protein. This could occur if the the newly expressed protein were able to enhance or "turn on" the translation of a particular gene, as certain proteins are known to do (Lewin 1997).

In this scenario, random variation is creating the rules by which cellular automata in turn use to create their patterns. In this sense, self-organization is being generated by these processes. On the other hand, one of the several patterns that could emerge could be selected on the basis of some superior adaptive trait. At this point, selection is constraining self-organization.

This brief discussion should make it clear that a combination of Darwinian and self-organizing processes has the potential to create much more evolutionary variety than either alone. It also suggests that it may be possible to develop an evolutionary theory in which both processes are taken into account. In this theory, both types of processes would be understood as the expression of some more fundamental concept that embraced both. Such a theory could then account for pure Darwinian processes as well as pure self-organizing processes as special cases of a more general evolutionary dynamics.

What would such a theory look like? How, specifically, might we construct a synthesis of Darwinian and self-organizing processes? An opening is suggested by Manfred Eigen:

 

"Theory and experiment show that Darwinian selection is a category of dynamic behavior reaching down to the molecular level...Selection is a consequence of non-linear dynamics. While equilibration leads to equipartition, thereby maximizing entropy, selection does just the contrary, i.e., it results from instabilities that minimize the uncertainties of remaining states."11

 

What Eigen means is that when a random minor fluctuation in the concentrations of several reactive species results in a stable new organizational pattern, that pattern is, in effect, selected. Though Eigen was describing his studies of reproducing viruses, the above quote could surely apply as well to other examples of non-linear dynamics, such as dissipative structures. Somewhat as a variant organism is selected by virtue of its greater adaptive fitness relative to other members of its species, a dissipative structure is selected because of its ability to maintain itself through absorption and dissipation of energy--in other words, because of its stability. This is a kind of fitness that the other organizational patterns of the reacting species don't have, and it is quite consistent with a Darwinian view. As Richard Dawkins observed, "Darwin's 'survival of the fittest' is really a special case of a more general law of survival of the stable."12

As I emphasized earlier, not all self-organizing processes can be understood in such Darwinian terms. Stuart Kauffman's autocatalytic networks are not the outcome of a random process, but are inevitable when the number of metabolic reactants becomes large enough. Because of this inevitability, these networks aren't selected, either, in the usual Darwinian sense of this word. Selection implies competition among several states; if the outcome is certain, there is no real competition.

If we focus not on the network as a whole, however, but on the individual reactions that make it up, we can see a process of random variation and natural selection at work. Though a network may emerge inevitably from these reactions, the particular reactions that survive in this form, as well as the manner in which they become interconnected, do seem to be a product of chance:

 

"In such a system, very many partially alternative pathways lead from a sufficiently large set of [starting] compounds to any target compound Z. In order that Z be synthesized by a connected catalyzed pathway, it is necessary not that any one pre-specified pathway to Z be catalyzed but that at least one reasonably high-yield pathway among the many possible pathways be catalyzed."13 (emphases mine).

 

In other words, many possible interconnected combinations of chemical reactions could emerge. Any product of one reaction might, in principle, catalyze several other reactions. Which products end up catalyzing which reactions depends on both how well a particular product can interact with another particular substance, as well as, most likely, its ability to find that substance among the large pool of other substances. This step surely involves a large measure of chance. When enough interactions like these are formed, on the other hand, the autocatalytic network comes into being, and survives because of its stability. This is the selection step. The survival of the network selects those particular reactions and their interconnections that make up the network. Not selected are all those substances that could not catalyze some other reactions.

When we look at autocatalysis in this way, it seems to me, it's quite analogous to the Darwinian processes we examined in Chapter 9. Each chemical reaction plays much the same role as a gene does in the cell, or as a neuron does in the brain. Just as genetic variation gives rise to different biological phenotypes, and neuronal variation to different behavioral phenotypes (memes), variation among the chemical reactions results in different configurations of these reactions. All of these configurations have some primitive phenotypes, the ability to grow and self-maintain to some extent; but one of them, by virtue of having a sufficient number of interconnections among its components, is autocatalytic. This is the phenotype that is selected.

So in an important sense, I believe all self-organizing processes can be understood in terms of a broader Darwinian theory. This is a very significant point, not simply because such a theory could unify two kinds of processes thought to be very different, but because some self-organizing processes, unlike traditional Darwinian ones, seem to have a pre-determined outcome. Though the particular chemical reactions, and their particular type of interconnections, may be a chance process, the emergence of autocatalytic networks, according to Kauffman, is inevitable. So random variation and natural selection can be entirely compatible with not simply what seems to be a higher form of life, but a particular type of higher form that is determined from the outset. Darwinism, here, operates within a framework that decides the outcome. The details of this outcome are contingent, that is, determined by circumstance; but the essence of the outcome is not.

Some Darwinists, such as Daniel Dennett (1995), argue that there is nothing in self-organizing processes that can't be subsumed under the general concept of Darwinism. Work by Eigen, Kauffman and others, in his view, is "deepening Darwin's dangerous idea, not overthrowing it."14 I find this view perfectly acceptable, if we understand that Darwinism so defined is quite a bit more general than what Darwin himself seemed to have in mind (at least in his public pronouncements); and if we now allow for the notion, just pointed out, that some evolutionary steps may have been inevitable. Dennett himself seems to think the latter point means no more than that natural selection is "complying with constraints, not fighting them."15. But surely the real significance of self-organizing phenomena depends on how often such constraints are encountered during evolution, and just how constraining they are--that is, to what extent they effectively eliminate all other possibilities. To take the extreme example--obviously not the case, but illustrative of the point--if every evolutionary step were completely constrained to one viable outcome, no one would think of the resulting process as Darwinian. Darwinism can incorporate some self-organization and be enriched; if it incorporates a great deal of self-organization, it (Darwinism) loses its identity as that process. As with evolutionary change itself, the line is not sharp, but that doesn't mean that one concept of evolution can't emerge as unrecognizably different from another.

 

Conclusions

Let's now step back a little, and summarize the main conclusions of the past two chapters. In Chapter 9, we saw that the twin concepts of random variation and natural selection, understood in general terms, could be applied to evolutionary events at every level of existence. Not only the biological evolution of cells and organisms, but the social evolution of these holons, and perhaps of still higher-level holons, involve Darwinian processes. In this chapter we have added self-organizing processes to the mix, and find that they, too, can be understood in terms of variation and selection. Is selection, then, a unifying concept of evolution? Is this what makes it all work?

Manfred Eigen seems to think so. "Generation of information," he says, "is connected with the principle of selection."16 Indeed, almost by definition. We saw earlier that Gregory Chaitin defines random strings or programs as having more information than ordered or patterned strings of the same length. Not any random string, however, but a particular one. The process by which one particular string is singled out is selection. So we might define selection as simply the process by which the random becomes non-random.

But exactly how are generation of information and selection connected? Does natural selection actually create information, all by itself? Eigen again: "Information generates itself in feedback loops via replication and selection."17 Eigen is basing this assertion largely on his studies with replicating viruses. Viruses can reproduce very quickly in the presence of a bacterial host, and so like bacteria themselves, they offer a useful model in which evolution of many generations can be followed in fairly short period of time. Though we would have to take great care in extrapolating results from them to multicellular organisms, if changes in not just quality but quantity of information could be demonstrated even in viruses, it would provide major support for the statement of Eigen's just quoted.

However, neither Eigen, nor any other scientist I'm aware of, has yet shown that the quantity of information can be increased in this manner in a reproducing form of existence. Eigen and others have shown that viruses can develop new genetically-determined traits through selection, such as resistance to certain enzymes. Their work also suggests that a population of viruses, which Eigen calls a quasi-species, may have some emergent properties (perhaps quasi-emergent would be a better term) not found in individual viruses. But they have not shown that a higher form of life, one with more genetic information, can emerge in this fashion. Moreover, as Micheal Behe and other creationists love to point out, artificial selection--in which the scientist determines the conditions to the which the virus or other evolving system must adapt--is very different from natural selection. In the latter, evolving forms of life adapt to whatever the prevailing conditions happen to be. When a scientist sets the conditions in the laboratory, they can be designed so as to maximize the adaptive advantage of the evolution of certain properties. Life evolving under these conditions would be expected to change much more rapidly and much more directly towards a particular endpoint than under natural conditions.

On the other hand, it does seem that some self-organizing systems may be able to generate information. Prigogine's dissipative structures maintain themselves at a higher level of energy than their starting components, which seems to imply that the system has acquired some kind of new information. Kauffman's autocatalytic networks accomplish the same thing. However, again, these are artificial systems, in which the conditions are set up by the scientist in the laboratory. In the case of autocatalytic networks, the system is not even artificial. It exists so far purely in theory, on a computer screen. Moreover, as we have seen, most self-organizing phenomena can't reproduce themselves, so they offer a very limited model for the evolution of life.

So we are still left with the question of how information accumulates in life--where it comes from. Perhaps Darwinian and self-organizing processes are sufficient to account for this accumulation, or perhaps not. In Chapter 8 I suggested, on the basis of an apparent information gap between levels of existence, that information might come from outside the evolving system. It's time to consider this possibility more seriously.


Related articles:

 


Source: http://www.geocities.com/andybalik/introduction.html
 


* * *


© Copyright Illuminati News, http://www.illuminati-news.com. Permission to re-send, post and place on web sites for non-commercial purposes, and if shown with no alterations or additions. Excerpts from the article are allowed, as long as they do not distort the concept of the same article. This notice must accompany all reposting.


Last Updated:
Monday, May 28, 2007 11:55:35 AM


 


 

Webdesign: Logo design web | web hosting guide | stock photos


Design downloaded from FreeWebTemplates.com
Free web design, web templates, web layouts, and website resources!