The Evolution of Natural Selection

Some of the essays on this webpage are like building blocks. I continue to think about them after I’ve written and posted them, and think of more things to say. Other events also enter the thought process. In this case, another event was reading Robert Wright’s latest book, Nonzero. That book takes as given that sometime shortly before the Neolithic, humans started evolving culturally much faster than they ever could or did evolve biologically, and that cultural evolution continues, to this day, to account for the very rapid growth of the functionality and complexity of human societies. He sees the development of such complexity as a directional impulse that is irreversible. He concludes that life has an underlying purpose, perhaps even a predefined goal, which may become apparent as humanity gets digitally fused into some internet-wired global brain.

Wright’s conclusion is mushy and for my money untenable but the way he gets to it is interesting. He brings a lot of evidence to bear on the whole sequence: inorganic soup to earliest life to the emergence of our own species, and then from there through tribes and chiefdoms and kingdoms to modern nation states and on. His description is aimed at demonstrating that when living things find it mutually advantageous to cooperate, they often do, and enhance their survival prospects in the process. Natural selection thus favors cooperation, and cooperation in turn leads to ever more complex and functionally adapted entities.

His description of cultural evolution is flawed by inadequate attention to what a culture actually is. This is something I address in detail in my forthcoming book, Culture Wars and the Global Village. But his ready assumption that cultural evolution exists, and that it works by group not individual selection, goes against mainstream anthropological opinion (see my essay, “Group Selection”). It emboldens me to run a bit farther with the whole idea.

Natural Selection and the Second Law of Thermodynamics:

When you have replicating entities that compete with each other for survival, then the ones best adapted to cope with the challenges will be the survivors. This sounds like a tautology, and it is. It is still a tautology when you spell out the challenges, eg too little food to go around, the existence of predators, etc.. But this proposition, tautological though it may be, is the irrefutable basis for the principle of natural selection, and explains why, over many generations, living things evolve. Natural selection, when it has enough time to work itself out, enables plants and animals to get bigger and better, ie more complex and more functional in terms of their environments, in defiance of the second law of thermodynamics.

That law says that things run down. Complexity degenerates into simplicity and ultimately into randomness. So we have natural selection and the second law of thermodynamics as the yin and yang of the universe as we know it. Shiva and Vishnu. The principles of destruction and regeneration. The general idea has been around for a long time.

Natural versus Artificial Selection:

As far as I know, humans are the only living creatures on our planet who have consciously practiced artificial selection. The Neolithic was only possible because some of our remote ancestors selected certain wild food grains outstanding both for nourishment and harvestability, then selected for planting individual plants within those species which were the most suitable, and kept it up until the present day, giving us what we now know as “improved varieties” of wheat, rice, barley, and other foodgrains. Similar approaches led not only to other vegetable foods, but to domestic animals. The development and refinement of “breeds” is still very much a part of the way modern people think and operate, in regard to such things as cattle and pigs (4H clubs), dogs (the American Kennel Club) and so forth.

There is a major difference between this kind of selection process and the natural selection that is our mainconcern here. There is a creator, a guiding intelligence, operating with a specific end in view for the human-directed process. There is no such guiding intelligence for natural selection, or at least there is nothing like a guiding intelligence that is provable. Indeed, the actual course evolution has taken through the ages strongly suggests to me that there is nothing more specific than the general principles I have outlined above, natural selection and the second law. That’s all you need to produce the results we can observe. To adduce more by way of first causes, or teleological purposes, is to fantasize. You can do it if you want, but it is logically unnecessary and superflous, and as a practical matter that kind of fantasizing can get you in trouble.

Four Stages of Natural Selection:

Life defies the second law of thermodynamics, not only because the principle of natural selection increasesthe functionality of individual biological entities, but because it encourages cooperative relationships between different kinds of entities, and such relationships can confer mutual advantage. The fact that that both the cooperators end up ahead of the game pulls them up, as it were, against the gravitational pull down to chaos and randomness of the second law. This is the main point of Wright’s book, and the evidence he assembles is impressive.

Living things evolve over time because of natural selection. But if the basic pattern of life itself should change, if biological life were to develop some new life form, still subject to the principle of natural selection, but in a new and unfamiliar way, could we say that the principle of natural selection was itself evolving? Let’s look a long way back, and then a much shorter way back, and then ahead, and see if we can see such a pattern.

Let’s call natural selection’s first stage “chemical evolution.” Several billion years ago there was no life on earth. In places a bunch of chemicals was swilling around at or near the earth’s surface in what some people like to call a primordial soup. The odds were enormously against any of these chemicals combining in ways that laid the foundations of life, but sometimes it happened; combinations of chemicalsoccasionally occurred that could replicate. For a long time, the results couldn’t really be called living, but once such compounds started reproducing copies of themselves, a very slow and creaky kind of natural selection began to operate. This all took place over a very long time, billions of years ago.

The second stage was biological evolution. A primitive replicating entity that was good at a given functionsometimes found its survival value enhanced by combining forces with a different kind of entity. Non-zero-sum relations (Wright’s thesis) increasingly impelled an evolution out of chemical chaos. Bacteria and other procaryotes emerged, then eucaryotic cells, then DNA. DNA was a triumph and major breakthrough for the whole evolutionary process. because of its ability to replicate its host in enormous detail. Once it had achieved this level of accuracy in replication, the selection process moved into a higher gear, and life as we know it evolved. This phase has been going on for perhaps a billion years (depending on when you consider it to have started). It is still continuing, despite recent disruptions resulting from human depredations.

The third stage is cultural evolution. Humans endowed with a capacity for speech and large brains developed a capacity for abstract thoughts. As they supplemented this capacity with increasingly sophisticated ways of generating and storing and reusing information, they created a new kind of environment, one in which memes, or thought patterns, could arise and provide bonds to unite groups larger than kin-based bands. Different groups in different areas, facing different challenges, developed distinctive packages of memes which we now know as cultures. Culturally differentiated groups began to compete with each other; some cultures survived and others went under. Modern cultures are therefore as much a product of a protracted evolutionary process as modern animals and vegetables. The specific mechanisms that govern natural selection for cultures are different from those that govern biological evolution, but each in its own way is the result of a long process of natural selection.

Cultural evolution proper began around twenty or thirty thousand years ago, when cultural changes began to accelerate, and outstripped the capacity of the human body and brain to keep up through genetically mandated adaptation.

Natural selection is now beginning to develop a new mutant, which I call memetic evolution. Our human world is becoming increasingly monocultural. Global problems require global solutions, and technological interconnectedness makes everybody more aware of everybody else. Natural selection among memes is not based on physical survival, as in biological evolution, or decided on the field of battle, as was often the case with cultural evolution, but by the collective judgments of peer groups of people, billions strong.

This four-fold division is artificial, and it conceals the fact that we are dealing with a continuous spectrum here rather than with clearly distinguished units. Furthermore, the different phases overlap in time; memetic selection has been happening throughout recorded history, while cultural selection has a way to go before it expires (e.g., Kosovo, Rwanda). However, my classification can be useful in demonstrating the insufficiently obvious point that natural selection is not only the prime cause of evolution, but is itself evolving.

Natural Selection and Theism:

I said at the outset that I didn’t buy Wright’s steamy conclusion about how all this zerosumness, this impulse toward more complex and cooperative arrangements, suggested a higher purpose, some kind of controlling destiny. As far as I am concerned, the second law of thermodynamics is there, it is a given, it is the way things are. I require no omniscient creator as its author. Likewise I require no further explanation of the principle of natural selection beyond the appreciation that it’s there, it makes sense, it’s the way things work. Things are the way they are now because of everything that happened in the past, and what is happening now will determine what happens next. Our destiny is to do our best to cope with our contemporary environment with all the intelligence and adaptability that are among the most distinctive qualities of our species. Curiosity has gotten us pretty far, and it will take us still farther. One of the more important things to be curious about, it seems to me, is the process that got us here. That, of course, is what this essay is about.

CSCoon 2/27/00

This entry was posted in Progressive Humanism. Bookmark the permalink.