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A Conversation With George C. Williams

by Frans Roes

am convinced that it is the light and the way." These are the final words in Adaptation and Natural Selection, George C. William's 1966 book about evolution. In the decades since the publication of this book, which became one of the most influential in its field, nothing has altered Williams's conviction that evolutionary theory is not just of intellectual interest but has much practical significance for human life.

A marine biologist by training, Williams took two sabbaticals to conduct fish research in Iceland, but he is most widely known as a theoretician. As early as 1957, he wrote a paper on senescence considered by some to be a cornerstone of modern evolutionary theory. Williams has also written passionately about the "moral unacceptability of natural selection" and the necessity of using our intelliqence to triumph over it. For a paper on evolutionary ethics, Williams came up with one of the most eye-catching titles in scientific literature: "Mother Nature Is a Wicked Old Witch."

Despite his strongly held convictions, Williams says that for him, controversy is what makes biology interesting. In years past, he defended reductionism (the idea that organisms can be adequately understood in terms of physics, chemistry, and the history of evolutionary change) when it was not fashionable to do so. More recently, he has explored the insights to be gained by applying evolutionary theory to medicine. His 1996 book, Evolution and Healing: The New Science of Darwinian Medicine (coauthored with Randolph Nesse, of the University of Michigan Medical School), stresses the importance of understanding the adaptive significance of symptoms such as fever rather than merely seeking immediate relief.

George C. Williams
George C. Williams 

George Williams taught biology for thirty years at the State University of New York at Stony Brook, where he is now professor emerittis. He is also editor of the Quarterly Review of Biology, which has been publishing thoughtful articles and book reviews about the life sciences for nearly three-quarters of century. Williams's latest book, The Pony Fishes Glow and Other Clues to Plan and Purpose in Nature, was published by BasicBooks as part of its Science Masters Series.


Frans Roes: Thirty years ago, in Adaptation and Natural Selection, you criticized some ideas in biology.

George Williams: I think that my main criticism in the book was directed at the general assumption that adaptation characterizes populations and species, rather than simply the individuals in the populations and species. What I did was take the position that natural selection works most effectively at the individual level, and adaptatious that are produced are adaptive for those individuals, in competition with other individuals of the same population, rather than for any collective well-being.

Frans Roes: Individual selection would mean that living organisms are not adapted to prevent the extinction of their owm species.

George Williams: That is right. Most evolving lineages, human or otherwise, when threatened with extinction, don't do anything special to avoid it. I presume that the last pair of passenger pigeons, once a very abundant bird in North America, now extinct, reproduced the same old way. Once the species had gotten extremely rare, it did nothing new and did not take any special measures, the way an individual would if threatened with death. On other hand, we humans in fact have not gone extinct as yet; all our closest relatives have, so I would presume that to some extent the current human biology may be biased in favor of attributes that make us less vulnerable to extinction.

Just what features raise or lower vulnerability to extinction is a generally neglected problem, but it is widely recognized that sexual reproduction helps to keep a population going. Sexual reproduction is a complicated process that is occasionally lost, thereby simplifying the reproductive process. As a general rule, though, in both plants and animals, once a line of descent loses the sexual process, nothing new ever comes of it. It won't branch into several new species the way a sexual species might. So asexual reproduction exclusively in any line of descent appears to be a dead end. If there has ever been a mammal that reproduced asexually, it is not around any more and has no descendants.

Frans Roes: If selection works at the individual level, why don't individuals live forever? Why do we grow old?

George Williams: Well, no matter how fit you keep yourself, sooner or later something will get you: an accident, a new epidemic, an attack by terrorists, or whatever. Even if you had eternal youth, this would obviously not assure that you live forever. So the interesting question is, once we attain our full youthful adulthood, why don't we just stay that way?

Suppose we could do that: let's wave a magic wand, and suddenly we have eternal youth. In evolution that would not be stable, because eternal youth does not abolish mortality. Let's say that half of us with this eternal youth managed to live to 100, a quarter to age 200, one-eighth to 300, and so on. A mutation that would confer some slight advantage in our twenties and thirties might well be favored, even if it causes us to drop dead at age 300. Most people are going to be alive in their twenties and thirties and thus get the benefits of whatever that mutation does, but since only one-eighth of the population is going to reach age 300, dropping dead then would be worth an advantage earlier in life. So the evaluation by natural selection of new genetic variability would be biased in favor of the earlier part of life histories and against the later part, until we had reevolved to something like the senescence we have now.

Frans Roes: But I read that sea anemones may live forever. How is this possible?

George Williams: The general rule is that anything that is passed on in reproduction does not undergo senescence. So things that can divide in two, with both halves going on, would ordinarily not deteriorate with increasing age. They wouldn't have the kind of trade-off that you have when there is something you can discard. We humans may discard our bodies, but our germ cells do not necessarily come to an end. We can pass them on in reproduction to people who in turn can pass them on. Asexually reproducing organisms such as sea anemones retain eternal youth for the same reason that our germ cells retain eternal youth. I think it is the British biologist Tom Kirkwood who invented the term "disposable soma." If you have a disposable soma, that soma will undergo senescence. If you don't, it won't.

Frans Roes: There are all sorts of wonderful adaptations, yet you write that natural selection never designs new machinery. Why did you write this?

George Williams: Because there is nothing in natural selection that looks ahead and plans ahead. All it can do is make use of variation that is present. Some things work better than others, and the ones that work better are the ones that tend to be preserved. And these are always preserved in relation to immediate circumstances, never in order to facilitate anything in the future.

Frans Roes: You also wrote that every organism shows features that are functionally arbitrary or even maladaptive.

George Williams: The human body is just full of illustrations of what are really either arbitrary or in many cases quite unfortunate legacies from prior history. Our respiratory system, for instance. Way back, half a billion years ago at least, some early vertebrate didn't have a respiratory system, but it had a digestive system with a way of taking in water at the front end and running it through a filter. That machinery turned out to be easily modified to facilitate respiration, to arrange some special mechanisms for exchanging gases with the environment when the organism got big enough to actually need that.

Ever since then, all descendant vertebrates have had the forward end of the digestive system and the forward end of the respiratory system very much involved with each other. This manifests itself in the human body with a crossing of the two systems in the throat. So there can be, and frequently are, traffic problems there, the extreme being that you choke to death because you are trying to eat something. If you could redesign it, you would have two completely separated systems, or they would be connected in a way that doesn't require any crossing of the two systems.

Frans Roes: Another seemingly maladaptive phenomenon: Why would a vital organ like the human male testis be outside the body, where it is quite vulnerable?

George Williams: For some reason, sperm development has to be at a lower temperature than the rest of the body. This is accomplished by the somewhat external scrotal structure. This certainly makes the testicles vulnerable, and I think an indication of this is that whenever mammals reproduce seasonally and don't need to be producing sperm for much of the year, the testicles are retracted into the body and only go back into the scrotum during the breeding season.

Frans Roes: But this sounds like an excuse: We don't know why testicles are outside the body, so it must be temperature.

George Williams: Oh no, I think it quite obviously is temperature because any time the testicular temperature is abnormally elevated, for instance by a high fever, sterility or defective sperm results.

Frans Roes: Still, I think this sounds like making the theory irrefutable.

George Williams: If you are talking about the general theory, it is not likely to be refutable by any one study. No single observation like this is going to make users of some major theoretical set of ideas abandon these ideas. What does happen is that you use evolutionary theory to make certain predictions and check on those predictions. More often than not, they turn out not to work. So you go back to the drawing board and try something else. You don't find the wrong ones being published in biological journals.

Frans Roes: But aren't people justified in saying, hey, there is a conspiracy going on of biologists who don't publish anything that is unfavorable to evolutionary theory?

George Williams: The same bias affects engineers. They calculate that if they did something a certain way, they would produce a better engine. They do it and try it out, and it turns out not to be better at all. So they go back and try something else. They do not claim to have refuted the laws of thermodynamics. These are not things that get published in the engineering journals. It is only the improvements that get published. Evolutionary theory works the same way: Use it to generate expectations and then check on them. If the expectations turn out as expected, then you have made a discovery that may be something important.

Darwin based his theory on generalizations that were strictly empirical. You can go out and see that organisms do vary, that variations are inherited, and that every organism is capable of increasing its numbers in sufficiently favorable circumstances. These are basic premises that can be checked directly. By contrast, physical theories, such as those that describe invisible atoms, are often not directly testable.

Frans Roes: In your latest book, you describe the biological creation process as being both "evil" and "abysmally stupid." What do you mean when you say this?

George Williams: Natural selection maximizes shortsighted selfishness, no matter how much pain or loss it produces. There are far more losers than winners, and great losses often arise from trivial gains. The killing of monkey infants for minor male reproductive gain is the example that most persuasively led me to use words like evil.

As to its stupidity, natural selection produces what seem to be ingenious devices, like eyes and hands and the human capacity for language, but a close examination shows these devices to be just the sorts of things that can arise from trial and error, with no modifications that would arise from any real understanding of the problems to be solved. As a result, all organisms are burdened with maladaptive historical legacies, such as the many problems that arise from the close association of the human reproductive and excretory systems.

Frans Roes: I found in your work several references to Buddhism. Do you have a special liking for Buddhism?

George Williams: My reading on this sort of thing is extremely limited, but as a doctrine I think Buddhism is more compatible with the spirit of scientific inquiry than what you get in the Old Testament. I think it is because of the explicit recognition in Buddhism that things are not naturally good. There is a lot of pain and suffering in the world, and that is because that's just the way the world is. And the way to overcome this is to live a certain way and to be resigned to the inevitable imperfections of life.

This is opposed to some Christian and Jewish traditions, in which everything is for the best to some extent, because it is God's will that things be this way. And if they don't seem right—well, that is because we don't really understand. In the Book of Job, for instance, no matter how many evils befall, you accept them and really don't admit that they are evil because they must have come from God. And opposing what God does is stupid because God is so powerful. Job's avoidance of rebellion against God has nothing to do with God being good or wise or anything like that; it's strictly because God is so powerful, and you don't fight something when you are so much weaker than that which you would fight.

Life and Death Fallacies

From The Pony Fish's Glow and Other Clues to Plan and Purpose in Nature, by George C. Williams. Copyright 1997 by George C. Williams. Reprinted by arrangement with BasicBooks.

Many traditional religions foster attitudes that ought to have disappeared as biological understanding accumulated over the last century. One of these might be termed the holy-corpse fallacy. When people die, their relatives and friends behave as if there were some moral significance in the dead body. They ignore the fact that the "last remains" are just that, material that happened, at the time of death, to provide the medium of expression for a human life. However long this complex human message was expressed is the duration of time in which the materials were coming and going. The tons of matter that at one time or another were part of a dead senior citizen are already dispersed throughout the terrestrial ecosystem. A small minority of the dead person's molecules are in orbit around the earth or sun. Cremation of the matter that happened to be there at the last minute merely hastens an inevitable process.

The holy-corpse fallacy once had support from the biological concept of protoplasm, the special living matter of an organism. Other matter may be entering and leaving a living cell, but it's protoplasm was presumably a stable entity that regulated this material flux. A dead person may have dead protoplasm, but it was presumably that person's very own protoplasm, and had been throughout his or her life. Protoplasm was often discussed in the biology courses I took in the 1940s. It is a term almost never heard today.

Another error is the moment-of-conception fallacy. The joining of a human egg and sperm defines a new and unique human genotype. It does not produce any human hopes and fears and memories or anything else of moral importance implied by the term human. The newly fertilized egg may have the potential for a fully human existence, but that potential was there even before fertilization. The same can be said of all the fertilizations that might have been. The penetration of that egg by one sperm meant an early death for millions of competing sperm. It destroyed all hope for those millions of other unique human genotypes.

The moment-of-conception fallacy implies that fertilization is a simple process with never a doubt as to whether it has or has not happened. In reality, the "moment" is a matter of some hours of complex activity. There are elaborate biochemical interactions between the sperm and various layers of the egg membrane. The sperm gradually breaks up, and only its nucleus is established in the egg. Then both egg and sperm nuclei initiate radical changes before the fusion of the two nuclei. Many of the developmental events following this fusion were predetermined during the production of the egg. Genes provided by the sperm do not have discernible effects until embryonic development is well under way. A strictly biological definition of humanity would have to specify some point in this elaborate program at which the egg and sperm have suddenly been endowed with a single human life.

There are other difficulties with defining humanity this way. If that single human life develops for a while and then divides to produce identical twins or triplets, are they to be considered one human being? This would be contrary to almost everyone's moral sensibilities. Recent observations have raised additional questions about the connection between biological and moral individuality. Early in development, fraternal twins from two separate, fertilized eggs may fuse and develop into what, at birth, is physically a single baby. Molecular techniques available today may show that such an individual is genetically different in various parts of its body. An apparently normal woman may have some genetically male tissues from what originated as her twin brother, or vice versa. The only realistic view is that a human life arises gradually, which is not much help in making personal decisions or devising public policy.

Trained as a sociologist, Amsterdam native Frans Roes has for much of the last decade written about evolutionary theory. His second book, The Naked Mole Rat: On Humans, Animals, and Evolution, was published (in Holland) in 1993. Roes is now working as an environmental adviser, consulting with firms on their fossil energy consumption, chemical use, and waste production.

[ Frans Roes, "A Conversation With George C. Williams," Nat. Hist. 107 (May): 10-13. ]

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