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Ernst Mayr Recounts 20th Century Evolution Battles 07/02/2004
A leading 20th century apostle of Darwinian evolution, Ernst Mayr, turned 100 recently. His mind still sharp, he recounted in the July 2 issue of Science¹ the battles that led to the neo-Darwinian synthesis in the 1940s. Surprising though it may be to some, there was no consensus on speciation, natural selection and other key evolutionary concepts for eighty years since Darwin published his book. Only in the 1940s did a compromise called the neo-Darwinian synthesis satisfy the majority of Darwinians. Neo-Darwinism still reigns today, despite strong minority positions such as punctuated equilibria and Gaia, along with a number of sects that deny certain aspects of the Synthesis.
Mayr lays the background of his youthful acceptance of evolution:

Curiously, I cannot pinpoint the age at which I became an evolutionist. I received all of my education in Germany, where evolution was not really controversial. In the gymnasium (equivalent to a U.S. high school), my biology teacher took evolution for granted. So, I am quite certain, did my parents--who, to interest their three teenage sons, subscribed to a popular natural history journal that accepted evolution as a fact. Indeed, in Germany at that time there was no Protestant fundamentalism. And after I had entered university, no one raised any questions about evolution, either in my medical curriculum or in my preparations for the Ph.D. Those who were unable to adopt creation as a plausible solution for biological diversity concluded that evolution was the only rational explanation for the living world. (Emphasis added in all quotes.)

Nevertheless, he continues, “Even though creationism was not a major issue, evolutionary biology was nonetheless badly split by controversies,” namely, “the causation of evolutionary change and the validity of various theories of evolution.” These seem pretty all-encompassing. He describes some of the early battles:

Philosophy of science: “... the philosophy of science at that time was totally dominated by physics and by typology (essentialism). This philosophy was appropriate for the physical sciences but entirely unsuitable as a foundation for theories dealing with biological populations....”
Sub-issues: “...the paradigm of Darwinian evolution was not a single theory, as Darwin always insisted, but was actually composed of five quite independent theories. Two of these were readily accepted by the Darwinians: the simple fact of evolution [sic] (the ‘non-constancy of species’ as Darwin called it) and the branching theory of common descent. The other three--gradual evolution, the multiplication of species, and natural selection--were accepted by only a minority of Darwin’s followers. Indeed, these three theories were not universally accepted until the so-called Evolutionary Synthesis of the 1940s.”
International rivalry: “Superimposed on these conceptual differences were others that arose because of the preferences of evolutionists in different countries. The evolutionary theories considered valid in England or in France were rejected in Germany or the United States. One powerful author in a particular country often could determine the thinking of all his fellow scientists.”
Discipline rivalry: “Finally, different evolutionary theories were often favored by scholars in different branches of biology--say, genetics, or developmental biology, or natural history.”
Gradualism vs. saltationism: “We naturalists thought that evolution was indeed a gradual process, as Darwin had always insisted. Our material provided hundreds of illustrations of widespread species that gradually changed throughout their geographic range. By contrast, most early Mendelians, impressed by the discontinuous nature of genetic changes (‘mutations’), thought that these mutations provided evidence for a saltational origin of new species.”
Biodiversity: The founders of population genetics accepted natural selection, but “Several historians have mistakenly thought that this synthesis within genetics had solved all the problems of Darwinism. That assumption, however, failed to take account of an important gap. One of the two major branches of evolutionary biology, the study of the origin of biodiversity, had been left out of the major treatises of Fisher, Haldane, and Wright.” Mayr claims that this problem had been solved by European taxonomists.
Paradox and Schism: “Thus, evolutionary biology around 1930 found itself in a curious position. It faced two major seemingly unsolved problems: the adaptive changes of populations and the origin of biodiversity.” For instance, “As a student in Germany in the 1920s, I belonged to a German school of evolutionary taxonomists that was unrepresented in the United States. Our tradition placed great stress on geographic variation within species, and particularly on the importance of geographic isolation and its role in leading to the origin of new species. It accepted a Lamarckian inheritance of newly acquired characters but simultaneously accepted natural selection as facilitating gradual evolution. We decisively rejected any saltational origin of new species, as had been postulated by DeVries.”
Object of selection: “The two belief systems had only one inconsistency--the object of natural selection. For the geneticists the object of selection had been the gene since the 1920s, but for most naturalists it was the individual. Elliot Sober showed how one could resolve this conflict. He pointed out that one must discriminate between selection of an object and selection for an object.”

Mayr claims that the taxonomists and the population geneticists had solved parts of the problem; all that remained was to get the parties together. That compromise was achieved by Theodosius Dobzhansky with Mayr’s assistance. He claims the neo-Darwinian synthesis that resulted has been remarkably stable, even through the discovery of DNA and the revolution in molecular genetics, but part of that stability has been due to enforcement: “At a meeting in Princeton in 1947, the new paradigm was fully acknowledged and it was confirmed again and again in the next 60 years. Whenever an author claimed to have found an error in the Synthesis, his claim was rapidly refuted.”
In his conclusion, Mayr notes that new battles have arisen over allopatric vs. sympatric speciation, the enormous amount of biodiversity, and non-allopatric genetic mechanisms such as “speciation by hybridization, by polyploidy and other chromosome rearrangements, by lateral gene transfer, and by symbiogenesis.” He regrets he will not be able to continue exploring the new frontiers of evolutionary biology.

¹Ernst Mayr, “80 Years of Watching the Evolutionary Scenery,” Science, Vol 305, Issue 5680, 46-47, 2 July 2004, [DOI: 10.1126/science.1100561].

Did you know that believers in natural selection were in the minority in the 1920s, and that many evolutionists believed in rapid, saltational change instead of gradualism? You heard one of the living legends of Darwinism, Ernst Mayr, say it himself. Notice how nothing has changed. Early 20th century evolutionists disagreed on the mechanism of evolution (natural selection, Lamarckism or other) on the pace of evolution (gradual vs. saltational), and on mechanism of speciation. Those seem like pretty major issues. How can Darwin’s hunch rise above the status of hypothesis without answers to these questions? The only things they agreed on were: (1) evolution is a fact, and (2) things change. The same controversies go on today; evolutionists fight over how species split into two, how fast things happen, and the role of natural selection, but they all dogmatically claim, still, that (1) evolution is a fact (a statement of belief, not science) and (2) things change (too vague to be called science; even creationists acknowledge that things change).
Mayr’s account sounds less like a scientific law emerging from the evidence, and more like a victory of two major factions of storytellers over rivals, until they agreed to give a little and meet in the middle (thesis vs. antithesis -> Synthesis). The new talking points to feed the students became: “Father Charlie was right about gradualism and natural selection, but Mendel has helped forge an even better story: mutations provide the raw material for variation, then natural selection preserves the fittest. We will call this neo-Darwinism.” Students, liking anything that is neo, thought this is cool. The official sound bite for reporters became, “We may have some disagreements about the mechanism of evolution, but all scientists agree evolution is a fact.” These short, pithy mythoids suffice to keep most peasants compliant.
Those interested in the relation of Mendel to Darwin will find this paragraph interesting:
When Mendel’s laws were rediscovered [sic] in 1900, there was widespread hope that they would lead to a unification of the conflicting theories on speciation. Unfortunately, it turned out that the three geneticists most interested in evolution--Bateson, DeVries, and Johannsen--were typologists and opted for a mutational origin (by saltation) of new species. Worse, they rejected gradual evolution through the natural selection of small variants. For their part, the naturalists erroneously thought that the geneticists had achieved a consensus based on saltational speciation, and this led to a long-lasting controversy between the naturalists and the early Mendelians.
Long-lasting, all right; it was about 47 years before the Darwinians found a way to incorporate Mendel’s inconvenient laws into their story.
Textbooks present Darwinism as if it were so intuitively obvious that late 19th century scientists instantly saw the light and embraced it, and lived happily ever after. As we know from frequent reports on Darwinism and Evolutionary Theory in these pages, controversies still rage about the mechanisms of evolution, the pace of evolution, and the mechanism of speciation. Nothing has changed except the power of the Darwin Party to enforce their views.
How tragic to hear that the Reformation was dead in Germany by the time Mayr went to school. The country where Martin Luther had taken his brave stand on the Word of God had cast off its heritage for a radical revolutionary, Ernst Haeckel, who replaced it with the Word of Charlie. The early Protestant reformers had the will to withstand the Catholic counter-reformation, but their heirs, asleep at the switch, let the Darwinian revolution take over with hardly a word of protest. So now the revolution has become the mainstream, controlling the propaganda outlets, the universities, the schools and the official creation myths of the culture. The rallying cry for the Darwinian revolution is “just-so storytelling by faith, not by lab work.” Instead of A Mighty Fortress Is Our God, the official anthem is (to the tune of For He’s a Jolly Good Fellow), “We all take Charlie for granted (3X), which nobody can deny.” Try to deny it and face the wrath of the counter-reformation (see 08/19/2003 headline).
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Today's E-Skeptic mail list is running a delightful (but long) interview of Ernst Mayr that originally ran in Skeptic Magazine in 2000:

The Grand Old Man of Evolution
An Interview with Evolutionary Biologist Ernst Mayr
First Published in Skeptic Magazine, Vol. 8 No. 1, in 2000

By Michael Shermer and Frank J. Sulloway

Ernst Mayr was born in Kempten, Germany, on July 5, 1904, making him, at age 95, the grand old man of evolutionary biology, one of the primary architects of the modern synthesis of genetic and evolutionary theory, and arguably one of the most influential scientists of the 20th century. His career interests have spanned a remarkable five different fields, including: (1) ornithology, (2) systematics, (3) zoogeography, (4) evolutionary theory, and (5) philosophy and history of science. Such broad research interests grew from his education at a German Gymnasium (the equivalent of American high school, but at that time considerably more demanding), followed by a Candidacy in Medicine at the University of Greifswald in 1925 and a Ph.D. in zoology at the University of Berlin in 1926.

His lab training was quickly followed by three field expeditions: (1) the Rothschild Expedition to Dutch New Guinea in 1928, (2) the University of Berlin expedition to the Mandated Territory of New Guinea in 1929, and (3) the American Museum of Natural History Whitney Expedition to the Solomon Islands in 1930. Upon his return from the field, Mayr landed a position as Curator of the Whitney-Rothschild Collection at the American Museum of Natural History in New York from 1932-1953, after which he began his long tenure at Harvard University in zoology from 1953 to the present, where he continues to make the trip into work several days a week.

Although Mayr is less well-known to the general public than Richard Dawkins, E. O. Wilson, or Stephen Jay Gould, his impact on his science has been both deep and far-reaching, and has been appropriately honored with membership in 45 scientific societies, 14 lectureships and visiting professorships, 16 honorary degrees, (including those from such prestigious institutions as the University of Bologna, Oxford and Cambridge Universities), and 20 special awards, including the Wallace Darwin Medal of the Linnean Society in 1958, the Darwin Medal from the Royal Society in 1984, the Sarton Medal of the History of Science Society in 1986, and the Barzan Prize, the Lewis Thomas Prize, and the Crawfoord Prize in 1999. He has authored a remarkable 21 books, 13 by himself, four co-authored, and four edited or co-edited, many of which have become classics in the field, including: Systematics and the Origin of Species (1942), Animal Species and Evolution (1963), The Growth of Biological Thought (1982), Toward a New Philosophy of Biology (1988), and, his latest, This Is Biology (1997). He has published a staggering 704 scientific papers for an average of 9.3 papers per year since 1925, and he has three more books in the works and numerous papers in press.

Mayr married Margarete Simon in 1935 (deceased in 1990). He has two daughters, five grandchildren, and eight great grandchildren. One of us (FJS) studied under Mayr at Harvard. Sulloway first met Mayr in 1967, when, as a junior at Harvard College, Sulloway was organizing the Harvard-Darwin Expedition to South America in order to make a series of films about Darwin's voyage. Mayr graciously agreed to chair the project's advisory committee, and he was later one of the readers of Sulloway's senior honor's thesis on Darwin and the Beagle's voyage. As a graduate student at Harvard, Sulloway took a seminar course in evolutionary theory taught by Mayr (together with Stephen Jay Gould), and he also served as Mayr's teaching assistant in several other courses. Mayr became Sulloway's closest and most influential mentor (Mayr privately told Shermer that Sulloway was the best student he ever had), and Sulloway's first book, Freud, Biologist of the Mind: Beyond the Psychoanalytic Legend (1979), was dedicated to Mayr.

We caught up with Mayr between work at Harvard and an evening lecture on evolution at his retirement community, on a beautiful fall New England day as he reflected on the great scientific issues of his long and esteemed career.

Skeptic: Historians are interested in the influence of family background on the development of a scientist's ideas, so we thought we might start by asking you to reflect on your own family and upbringing.

Mayr: I was a very lucky boy. I was the middle of three brothers, and my parents were very much interested in nature. My father was a judge, my mother was a housewife, as was the norm in those days, and both were very intelligent and thoughtful people. Every Sunday we went on a nature hike from our little German town, Würzburg. My parents knew the flora and fauna of the area-they knew every mushroom in the woods, where the heron colony lived, and so on. So I was raised as a young naturalist, and this is very important because when you look at the people usually mentioned as the architects of the original synthesis [the evolutionary synthesis of paleontology and genetics]-Theodosius Dobzhansky, Julian Huxley, G. Ledyard Stebbins, myself, and so forth-we all started out as young naturalists, or as Darwin said of himself, were "born a naturalist." The one exception was George Gaylord Simpson, who didn't take an interest in nature until he was a senior in college. He was an English literature major before he switched to science. As a result, he never really understood the species concept because he didn't have a personal acquaintance with nature.

Skeptic: So you feel that in order to really understand evolution on a deep level you have to have a passion for nature from having been involved in it directly-it's not something you can pick up in a textbook.

Mayr: Very few people succeed in picking it up later, and if they do it is only one side of nature. Birdwatchers, for example, know a handful of species very well but they may not know the surrounding ecosystem.

Skeptic: Darwin once wrote: "About thirty years ago there was much talk that geologists ought only to observe and not theorize. I well remember someone saying that at this rate a man might as well go into a gravel-pit and count the pebbles and describe the colours. How odd it is that anyone should not see that all observation must be for or against some view if it is to be of any service!" How does one make the transition from being a pebble counter to a theoretician?

Mayr: The transition happens automatically as you get older and develops from years of experience. You get a "feel" for nature. For example, I'll be reading a paper in which the author makes some observation and I'll think "no, that can't be," and that comes from experience.

Skeptic: Why do some scientists, like yourself, have a bent for the theoretical and others do not?

Mayr: I'm not sure, but in my case it came from my education. I went to a German Gymnasium , which was much more demanding than American high schools, and they train students to ask critical questions instead of just accumulating knowledge.

Skeptic: They taught you how to think?

Mayr: Yes, the emphasis was on principles laid down by Wilhelm von Humboldt when he founded the University of Berlin in 1810-the whole idea was that our culture ultimately goes back to the Greeks and that deep thinking comes from dealing with the most fundamental questions about nature. I have always said that my achievements are due to this heritage of the culture of the German Gymnasium.

Skeptic: Research shows that when children lose a parent early in life that loss influences the way they develop as thinkers; and oftentimes elder siblings become surrogate parents to their younger siblings. How did the loss of your father when you were 12 affect you and change the relationship with your older brother?

Mayr: The minute my father died my older brother felt it was his duty to become the father of the family. But this was the last thing I wanted-I wasn't going to let him tell me what to do and what not to do. And, of course, I wanted to excel over him, so even though he was three years older I worked very hard as a student and even finished before him, earning my Ph.D. at the age of 21.

Skeptic: How did those field expeditions supplement your education?

Mayr: For two years I was in New Guinea, and I was in the Solomon Islands for nine months, and I became a specialist in ornithology. In fact, I came to the United States of America because the Natural History Museum in New York had these fantastic collections from the South Sea islands, but no specialist to work them up. When they looked around for someone to hire, they found out that I was the most qualified. That's how I came to be in America.

Skeptic: Were there social reasons to emigrate to America as well?

Mayr: Oh yes. The Communists and the Nazis were fighting, the Weimar Republic was trying to hang on, and there was a lot of turmoil. I came to America in January of 1931 and although my position at the American Museum of Natural History was a temporary one, I was very anti-Nazi. So there was no way I could return. Fortunately, the museum bought the greatest bird collection in the world from Lord Rothschild in England-280,000 bird skins-and they needed a curator, so it immediately dropped into my lap.

Skeptic: In many ways your life and career have paralleled those of Darwin and Wallace, particularly with regard to your three collecting expeditions. For you, were these explorations what the Galápagos Islands were for Darwin and the Malay Archipelago was for Wallace? Did you experience a scientific epiphany, or did your scientific ideas develop gradually?

Mayr: In New Guinea I could really study evolutionary biology's two major problems. First the origin of adaptation-why do we have eyes and why do species interact as they do? The second is the origin of diversity-why do we have tiny bacteria and giant sequoias, elephants and hummingbirds? When you work in islands you can see the changes from island to island. In New Guinea you see this from mountain to mountain. Every mountain had about the same number of bird species, but they differed from range to range. And these two problems of adaptation and diversity lead to solving the problem of the process of speciation. This has been the major focus throughout my career, from my first book, Systematics and the Origin of Species, to the present. And that book has just been reprinted after 54 years, which tells us that it is a classic.

Skeptic: What you are saying is that in order to properly study evolution you need an intuitive feel for organisms and ecosystems, and to acquire that you have to go there and see it.

Mayr: Correct. Geneticists studying guinea pigs in cages cannot see the evolutionary process. To truly understand species as independent separate reproductive communities you need to see them in nature. These field experiences led me to produce a definition of a biological species in 1945 which is still accepted today.

Skeptic: In fact, one of us (MS) had to memorize that definition in a course on evolutionary biology: "A species is a group of actually or potentially interbreeding natural populations reproductively isolated from other such populations." But this brings up the question of whether the species level of classification represents something that actually exists in nature. When you went to New Guinea you recruited the assistance of indigenous peoples in capturing birds. In the process, you learned a great deal from them about their knowledge of the various species living in their local environment. Did the fact that they classified the birds in a remarkably similar fashion to that of a professional ornithologist convince you that "species" really do exist in nature and are not just arbitrary units in the minds of biologists?

Mayr: Yes, that is what I mean about going out into the field.

Skeptic: In his book Dinosaur Lives, the paleontologist Jack Horner argues that the Linnaean classification system, which was constructed with a creationist model in mind, is a significant inhibitor to a deep understanding of evolution because these Linnaean "kinds" imply a reproductively isolated fixity from other "kinds," thus making it difficult to grasp species change over deep time. Horner argues that we should think of organisms as variations, like ever-evolving computer software programs: Hominid 7.1, 7.2, 7.3, and so on, where 7.1 = Homo erectus, 7.2 = Homo neanderthalensis, 7.3 = Homo sapiens . Is cladistics a good solution to the Linnaean anti-evolutionary system?

Mayr: Let's not get into cladistics. Cladistic claims lead to all sorts of conclusions that are misleading. If we want to find out if a group of organisms is a species, we have to have a method. We can divide them by common characteristics, which is sound. When we classify we make classes, and classes are groups that have features similar to each other. Cladism is a good system for determining phylogeny and descent, but it is not a good classification of living organisms. I accept cladistic analysis, which is a very good method to determine whether the characteristics of a group were derived from a common ancestor, but you cannot arrange things merely by descent without coming into total conflict with degrees of similarity, which is the whole meaning of classification.

Skeptic: You were born in 1904 when the grand old man of biology was Alfred Russel Wallace, who was 84 (and who would live to be 91). Evolutionary biology was still largely pursued by naturalists and was mostly an observational enterprise. The theory was still struggling for acceptance as a serious science. Looking back on the century, give us your opinion on the most significant contributions to evolutionary biology that have helped to elevate it to the status it holds today.

Mayr: The first one was the great debate that led to the evolutionary synthesis. Dobzhansky's book in 1937, Genetics and the Origin of Species, was very crucial because he was a "born naturalist," became a beetle specialist and so forth.Then at the age of 27 he came to America, worked for 10 years in Morgan's lab where he learned all about the genetic aspects of organisms, then combined the two.

Skeptic: Did Dobzhansky's book influence your work significantly?

Mayr: It didn't change it, but it filled in the gaps in my knowledge of genetics. Dobzhansky's book was still weak in the diversity aspects. He made a good start on defining the isolating mechanisms, but he erred by including geographic barriers among them. At the time, however, everyone thought that now all the problems were solved. And it was almost true. But there was still one major problem and that was the relative role of the gene versus the individual. I accepted the individual as the target of selection. Geneticists said that evolution is a change in gene frequencies among populations. But this is nonsense. Changes in gene frequencies are the result of evolution, not the mechanism . By about 1970s the majority of evolutionary biologists agreed that the individual was the primary target of selection.

Skeptic: What about group selection?

Mayr: George Williams and Richard Dawkins have made a mistake, in my opinion, in completely rejecting group selection. But we have to be careful here to define what we mean by a group. There are different kinds of groups. There is one type of group that is a target of selection, and that is the social group. Darwin knew this and identified it very clearly in 1871 in The Descent of Man. Hominid groups of hunter-gatherers were constantly competing with other hominid groups; some were superior and succeeded and others were not. It becomes quite clear that those groups who had highly cooperative and altruistic individuals were more successful than the ones torn apart by internal strife and egotism.

Skeptic: The social environment is as important as the physical environment?

Mayr: The essential point is that if you are altruistic and make your group more successful, you thereby also increase the fitness of the altruistic individual (yourself)!

Skeptic: But isn't it still the individual being selected for these characteristics, not the group?

Mayr: There is no question that the groups that were most successful had these individuals that were cooperative and altruistic, and those traits are genetic. But the group itself was the unit that was selected.

Skeptic: You developed your theory of allopatric speciation in the 1940s and 1950s. In the 1970s Niles Eldredge and Stephen Jay Gould applied that to the fossil record and called it punctuated equilibrium. Was this just a spinoff from what you had already done? What was new in punctuated equilibrium?

Mayr: I published that theory in a 1954 paper ("Change of Genetic Environment and Evolution," in Huxley, J., A.C. Hardy, and E. B. Ford, Eds., Evolution as a Process, London: Allen and Unwin), and I clearly related it to paleontology. Darwin argued that the fossil record is very incomplete because some species fossilize better than others. But what I derived from my research in the South Sea Islands is that in these isolated little populations it is much easier to make a genetic restructuring because when the numbers are small it takes rather few steps to become a new species. A small local population that changes very rapidly. I noted that you are never going to find evidence of a small local population that changed very rapidly in the fossil record. My essential point was that gradual populational shifts in founder populations appear in the fossil record as gaps.

Skeptic: Isn't that what Eldredge and Gould argued in their 1972 paper, citing your 1963 book Animal Species and Evolution several times?

Mayr: Gould was my course assistant at Harvard where I presented this theory again and again for three years. So he knew it thoroughly. So did Eldredge. In fact, in his 1971 paper Eldredge credited me with it. But that was lost over time.

Skeptic: Okay, but since you are also a historian and philosopher of science surely you recognize that there is a social factor here-the marketing and selling of an idea to a community of scientists.

Mayr: There are two kinds of scientists: media scientists and scientists' scientists. Gould, Dawkins and E.O. Wilson are media scientists (in the sense of publishing for the public).

Skeptic: Hasn't Wilson taken your early philosophy of biology distinction between how and why questions to the nth degree in Consilience in looking for the ultimate causes of human behavior?

Mayr: Wilson is difficult to evaluate. To give him justice, he is a tremendous enthusiast. He is always euphoric. The future is always beautiful. He's an evangelist, a scientific evangelist.

Skeptic: You are smiling when you say that.

Mayr: He's such a nice guy and so optimistic. Maybe because I grew up in Germany where things always went wrong, and I lost my father at a young age, I grew up to be a realist, maybe even a pessimist. I can't make all these enormous predictions as Wilson does in his books.

Skeptic: How does evolution as a historical science differ from experimental sciences?

Mayr: If you go to the literature in the philosophy of science you read about how experiment is the key to science. Hell no! Experiment in evolutionary biology is not useful at all except in certain cases. Darwin's method of asking "why" questions, then developing historical analogies, is how we "test" evolutionary hypotheses. If you want to explain why the dinosaurs became extinct you cannot run an experiment. You construct a scenario and see how well it explains the data. Could it have been microbes that wiped them out? Gradual environmental changes? A meteor? You see which of these different scenarios best explains all the data.

If Wilson has taken anything of mine without giving sufficient credit it would be the theory of island biogeography. You will find papers by me in 1939 and 1941 about continuous colonization and extinction.Wilson and MacArthur have even used figures that I published in those papers, but nowhere do they say that this theory of theirs was similar to mine. And the irony is that they may have never noticed the similarity.

Skeptic: Now wait a moment. Are you talking about Robert MacArthur and E. O. Wilson's theory of island biogeography? Are you saying that it is a derivative of your own ideas?

Mayr: I published the fundamental principles of that theory in 1939 and 1941. Others have pointed this out as well. It's not just my claim. But MacArthur and Wilson probably didn't think they were the same ideas because they believe something isn't scientific until it has been translated into mathematics, which they did.

Skeptic: You mean the equilibrium model?

Mayr: Yes, but they didn't realize that this is dangerous because there are too many exceptions and, of course, you can be proven wrong. For example, they were wrong in their predictions about bird colonization of Krakatoa and Hawaii. So Olson wrote this paper that said that island biogeography is dead. But because I did not make my ideas mathematical they are still viable science.

Skeptic: Are you saying that they were wrong because they gave incorrect figures, or that they were wrong to even be making such specific predictions?

Mayr: The mistake is in thinking that through mathematical formulae, you can arrive at the truth. That's wrong. I used the naturalist's way of thinking and predicted that there should be, say, 73 species colonizing or whatever. I didn't use any formula or mathematics. I just used the empirical evidence. I find that this invariably gives you better figures. The problem is the belief that mathematics is the royal road to truth.

Skeptic: Is this a problem of physics envy or reductionism?

Mayr: Wilson is just full of physics envy. Wilson was always trying to get mathematicians into the department. He's entitled to that, and he might have been right, but it turns out that he was not right.

Skeptic: In 20th century philosophy and history of science, the publication of Thomas Kuhn's classic work The Structure of Scientific Revolutions (1962) appears to mark a watershed. One could almost say there was a paradigm shift in this field, from science as progressivism to science as social constructivism. How would you characterize this shift and, indeed, is this the watershed that many think it is?

Mayr: Kuhn's description of how scientific revolutions happen does not apply to any biological revolution. To be very frank, I cannot understand how this book could have been such a success. The general thesis was not new, and when he did assert specific claims he was almost always wrong!

Kuhn's book mainly appealed to historians and social scientists. It was they who built it up into a big thing. It was vague, and vagueness always appeals to historians and social scientists.

Skeptic: Do the biological sciences need a different explanation for how they developed?

Mayr: My recent book, This Is Biology, if I say so myself, is in many ways quite revolutionary. I don't think anyone before me has said quite so strongly, and documented so carefully, the differences between the physical and biological sciences. The physical sciences have characteristics to them that do not help us understand the biological sciences, and the biological sciences have characteristics to them that are not applicable to inanimate objects. This Is Biology should have had a much greater impact than Kuhn's book. I get letters from scientists saying that This Is Biology has changed their whole way of thinking about these problems, but the general public doesn't even know about the book.

Skeptic: How has your personal study of the history and philosophy of biology influenced the way you do science, and how has the way you do science affected your interpretation of the history of biology?

Mayr: The problem with the history of science profession today is that historians have little training in the sciences so they don't really understand the importance of the development of scientific ideas. They give you all these different social and cultural influences on a scientist's thoughts, but not enough on the ideas themselves. These historians need to take courses in biology so that they really understand how these historical ideas fit into the larger picture of the science.

Michael Ruse, for example, is not trained as a biologist so his knowledge of biology is limited. He says rather questionable things and he does not realize that he is not fully qualified. Richard Lewontin is brilliant, but his theorizing is affected by his Marxist political beliefs. This is the problem with philosophy of science today. There needs to be more science and less philosophy.

Skeptic: Do you acknowledge that social influences do shape the development of a scientists' ideas? It seems fairly clear, for example, that Darwin's idea of natural selection was indirectly influenced by Adam Smith's concept of the invisible hand. Natural selection is, in fact, the invisible hand of nature. But I suspect you would say that it doesn't matter because it is a correct interpretation of nature.

Mayr: Well, actually, Darwin's metaphor of selection turned out to be wrong. Natural selection is not a process of selection, it is a process of elimination. Herbert Spencer, who was otherwise usually wrong, had the right idea of the "survival of the fittest," defined as those individuals that have certain characteristics that prevent them from being eliminated. Nothing is being selected. Nature is just eliminating the less fit.

Skeptic: Um, that's a debatable point. Is nature selecting for certain traits or selecting against other traits? It's not just eliminating, it is also selecting for certain characteristics, such as bigger brains. Or are you saying there was simply a selection against smaller brains?

Mayr: We have to be careful here to use the right words. You have to make a distinction between selection of and selection for. Certain individuals survived because they had certain characteristics, but they weren't selected. The process consists of eliminating all the others. There is also an important distinction between natural selection and sexual selection. In sexual selection the female is actually selecting males for certain traits, and this is different from natural selection.

Skeptic: To you, all these debates about selfish genes and group selection and punctuated equilibrium must seem like minor variations on Darwin's grand idea.

Mayr: I've said this many times. All these discussions over the years haven't affected Darwin's basic ideas one bit. The only change I make is that I consider the production of variation as part of natural selection. They are inseparable. Each is meaningless without the other. Natural selection is a two-step process: (1) variations produced, and (2) variations sorted, with the elimination of the less fit so that you end up with a "selection" of the best.

Skeptic: Looking forward as well as back, what's important now in evolutionary theory, and what do you anticipate on the horizon?

Mayr: The basic theory has not really changed in the last 30-50 years, and I have a very strong feeling that it isn't going to change much in the next 30-50 years. We are fine-tuning the theory, for example, gaining a deeper understanding of the genetics of evolutionary change. If you look through the most prestigious scientific journals in evolutionary biology today, just about every paper is devoted to some aspect of DNA.

Skeptic: Outside of evolutionary theory, what are some of the great mysteries remaining to be solved?

Mayr: Where are the greatest gaps in our knowledge? Three:

The brain. We understand neurons remarkably well. What we don't understand is their interactions. Just how do the billions of neurons in my brain remember my childhood experiences? What constellation of connections between neurons triggered some memory that was previously hidden? This business of the interaction of the components of complex systems is a field with an exciting future.

In a similar way there are still problems to solve in understanding embryonic development and how genes code for cellular differentiation. And how does the environment of the surrounding tissues affect that development? There is much work here still to be done.

Ecosystems: How do different species interact in a complex ecosystem to produce equilibrium and change?

Skeptic: Let's shift to another hot topic in the field-sociobiology and evolutionary psychology. Are these just spin-offs from Darwin?

Mayr: I don't use the word sociobiology. Neither do people like William Hamilton, Richard Alexander, or Robert Trivers. I think Wilson was envious, in fact, that others had contributed to the evolutionary synthesis, so he wanted to create another great synthesis. So he nominated social behavior as a candidate and called it a synthesis.

Skeptic: Surely you don't object to the principle of applying Darwinian thinking to studying social behavior?

Mayr: Lots of people were already doing that. And, furthermore, look at his sociobiology- most of that was already done before by ethologists. And he left out a lot. He neglected the establishment and maintenance of social rank order. He completely ignored the study of social migrations, which had been done for decades-this is the study of social behavior. So he singled out portions, what I call selection for reproductive success, and calls it sociobiology.

Mayr: I'm sure there are areas where you can still make major contributions, but they just happened not to pick the right areas! Gould, for example, has this big volume on evolution soon to come out. So over the years he has launched these trial balloons to see how they float. For example, his original punctuated equilibrium paper largely followed my 1954 paper. But then in 1980 he came out with another version that was very saltational, and deemed that it completely refuted the evolutionary synthesis, and that we need to revive Goldschmidt, and all that. This was total nonsense. Then five years later he revised it again and you don't see a word about Goldschmidt and saltation in his recent writing. That's what makes people like Gould unpopular. He should understand that. As for his fight with the British about contingency, well, they are both right if you look at it in the light of the two-step process of natural selection of variation produced and variation selected; there is an element of predictability and randomness in both. I fully endorse adaptation, but like Gould I strongly endorse the frequency of contingency.

Skeptic: It seems like ego and personality can sometimes get in the way of resolving these great debates.

Mayr: That's why I spoke of the media scientists. That's a problem. On the occasion of my 94th birthday a German newspaper, the Frankfurter Allgemeine Zeitung, which is the New York Times of Germany, wrote an article about me. When he interviewed scientists in the field he got comments of the highest praise, such as "one of the leading scientists in the world," but when the author talked to the man in the street they never heard of me.

Skeptic: So you feel you have not gotten the recognition your ideas deserve.

Mayr: Of course I have received enormous recognition by peers. Just look at the list of my honors, but I don't write for recognition. I've often been asked to write popular books, or my autobiography, but these would only interfere with what I see as more important scientific research. I'm not after that kind of recognition. I have been disappointed that the public isn't more discriminating.

Skeptic: Looking back, who were the two or three most influential people on your career and your thinking as a scientist? Who were your heroes?

Mayr: As a student, ornithologist Erwin Stresemann was my hero. Later on Dobzhansky. Now? I would have to say Darwin.

Skeptic: To what do you attribute Darwin's greatness?

Mayr: First, he was a brilliant observer. Everything he saw he asked questions about. He wanted to know why things were a certain way. He was always asking questions. Then he let the facts speak for themselves. Plus, of course, he was very intelligent.

Skeptic: But why Darwin and not Lyell or Huxley or one of the other brilliant men of the age?

Mayr: Because they were unable to see the data in a new light. Lyell was never quite able to accept the idea of evolution even in the face of the overwhelming evidence. Darwin was able to give up his preconceived ideas in the face of new evidence. Most people cannot do that. Then he had this incredible curiosity. Read the Voyage of the Beagle again. On every page he asks questions. With every new place they visited he asked questions. He was not a narrow specialist. He was interested in everything. In that respect I am very similar to Darwin. All my life I have been interested in a wide variety of ideas and subjects.

Skeptic: What is the proper relation between science and religion? Where do they intersect, if at all, and where are they in conflict?

Mayr: Well, I have a different definition of religion. All my atheist friends are deeply religious. They don't believe in God or anything supernatural, but they believe that they don't live in this world just to have a good time, but to improve mankind.

Skeptic: Do you consider yourself a humanist?

Mayr: Yes, I do.

Skeptic: You don't believe in God, but are you an agnostic or an atheist?

Mayr: I have the honesty to say I'm an atheist. There is nothing that supports the idea of a personal God. On the other hand, famous evolutionists such as Dobzhansky were firm believers in a personal God. He would work as a scientist all week and then on Sunday get down on his knees and pray to God.

Skeptic: What accounts for this style of thinking?

Mayr: Frankly I've never been able to understand it because you would need two totally different compartments in your brain, one that deals with religion and the other with everything else.

Skeptic: What can we expect from your pen next?

Mayr: I'm working on three more books. I've got one coming out soon with Jared Diamond on the birds of northern Melanesia. Then I've written a short book, entitled simply Evolution, that will be for general readers. And I'm doing a hermeneutics-a type of content analysis-of every sentence Darwin wrote in The Origin of Species , to see where he changed his mind and how he developed his ideas.

Skeptic: Someday someone is going to write your biography. How would you most like to be remembered as a scientist?

Mayr: One of the things that most people don't see is that basically I'm a modest person. They think I'm a great egotist and pusher of my own ideas. But I'm a humble man. I just want to understand nature and make a contribution to the body of knowledge about the natural world. And nothing else.

I will add that except for losing my father when I was 12, and my wife a few years ago, I've been an extraordinarily lucky person.

Skeptic: As has science for the contributions of Ernst Mayr. Thank you.

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