This is the second in a series of postings by a guest blogger, Arlin Stoltzfus. You can read the first part at: Introduction to "The Curious Disconnect". Arlin is challenging the status quo in modern evolutionary theory. He's not alone in this challenge but it's important to distinguish between kooks who don't know what they're talking about and serious thinkers who have something to say. Arlin is going to explain to you why everything you thought you knew about mutationism is wrong. I'm happy to give him a chance to post on Sandwalk.This will be on the exam.
The Curious Disconnect
The Curious Disconnect is the blog of evolutionary biologist Arlin Stoltzfus, available at www.molevol.org/cdblog. An updated version of the post below will be maintained at www.molevol.org/cdblog/mutationism_myth1 (Arlin Stoltzfus, ©2010)
The "Mutationism" Myth I. The Monk's Lost Code and the Great Confusion
The mutationism myth tells the story of how, just over a century ago, the scientific community responded to the discovery of Mendelian genetics by discarding Darwinism, and how Darwinism subsequently was restored.Our journey to explore The Curious Disconnect-- the gap between how we think about evolution and how we might think if we were freed from historical baggage-- begins with the Mutationism Myth. In this, the first of four parts, we are not going to confront any tough scientific or conceptual issues. Instead, we are just going to review an odd story about our intellectual history.
The Mutationism Story
While "myth" has the connotation of falsehood, the story that a myth tells isn't necessarily a false one. The mutationism myth, at least, is anchored in historical events.1
The mutationism myth tells the story of how, just over a century ago, the scientific community responded to the discovery of Mendelian genetics by discarding Darwinism, and how Darwinism subsequently was restored. The villains of the story are the influential early geneticists or "Mendelians" who saw genetics as a refutation of Darwinism; the heroes are first, the founders of population genetics, theoreticians who sorted everything out in favor of Darwinism by about 1930, and second, the architects of the Modern Synthesis, activists who popularized and institutionalized what we're calling "Darwinism 2.0".
This story has been re-told in secondary sources for nearly 50 years, though I sense that the frequency is decreasing as this episode passes into ancient history. To find examples, try looking up "mutationism" (sometimes "Mendelism" or even "saltationism") in the index of a book about evolution.
I encourage you to consult whatever sources you have and to share the stories that you find. Note that you won't always be successful. A quick survey of several dozen contemporary books on my shelf reveals that most don't address this episode specifically (a notable absence, in some cases 2); some tell the mutationism myth with varying degrees of panache; and a few provide a historical account rather than a myth. The few historical accounts that I found were in Gould's 2002 The Structure of Evolutionary Theory, Strickberger's 1990 textbook Evolution, and the Wikipedia entry on "Mutationism".
Sample stories
Lets look at a few examples of the mutationism story. Readers who want to check out a freely available online source from the scholarly literature may refer to Ayala and Fitch, 1997 (http://www.ncbi.nlm.nih.gov/pubmed/9223250?dopt=Citation). One example that really caught my eye is not from scientific literature, but from the 2005 obituary for Ernst Mayr in The Economist:
It was not that biologists had given up on evolution by the 1940s-quite the contrary. But they had got very confused about its mechanism. . . . The geneticists of the early 20th century did not help. They rediscovered the laws of inheritance first developed 40 years earlier by Gregor Mendel, an unsung Moravian monk. They also discovered the idea of genetic mutation. But instead of linking these things to natural selection, they came up with the idea of "saltation"-in other words, sudden mutational shifts from one well-adapted species to another. Nor, the geneticists complained, had there been enough time for natural selection to do its work, given what they had discovered about the rate at which mutations occur, and the fact that most mutations are deleterious. It was all a bit of a mess. . .Mr Mayr's advantage over the laboratory-bound biologists who had hijacked and diluted Darwin's legacy was that, like Darwin, he was a naturalist-and a good one. (anonymous, 2005)
Of course, this is a magazine article, written by anonymous staff writers-- typically one doesn't see such florid language in the scholarly literature. But did the staff writers of the Economist (representing elite opinion) really originate this story, based on their own personal recollections of the 1930's? Of course not. Mayr himself popularized the image of geneticists as laboratory-bound geeks lacking the organic insight of "naturalists". This disdain for the geneticists who "hijacked" Darwin's legacy is readily apparent when evolutionary writers depict geneticists as fools holding "beliefs" that have "obvious inadequacies", unable to understand or "grasp" their own scientific findings:
"It is hard for us to comprehend but, in the early years of this century when the phenomenon of mutation was first named, it was regarded not as a necessary part of Darwinian theory but as an alternative theory of evolution! There was a school of geneticists called the mutationists, which included such famous names as Hugo de Vries and William Bateson among the early rediscoverers of Mendel's principles of heredity, Wilhelm Johannsen the inventor of the word gene, and Thomas Hunt Morgan the father of the chromosome theory of heredity. . . Mendelian genetics was thought of, not as the central plank of Darwinism that it is today, but as antithetical to Darwinism. . . It is extremely hard for the modern mind to respond to this idea with anything but mirth" (Dawkins, 1987, p. 305)
"According to mutationism, random changes in the hereditary material are sufficient for adaptation without much, or any, selection at all. Mutations just somehow happen to be adaptive, the right changes simply manage to occur. The inadequacies of this view are obvious" (Cronin, 1991, p. 47).
"Darwin knew nothing of this [i.e., genetics] but as it turned out, his ignorance was sublimely irrelevant to the problem he was really interested in tackling: evolution. This point was not fully grasped by biologists. Many early geneticists at the dawn of the 20th century, thought their discoveries of the fundamental principles of genetics somehow cast doubt [on], or rendered obsolete, the concept of natural selection. It took several decades of experimentation and theoretical (including mathematical) analysis to show not only that there was no conflict inherent between the emerging results of genetics and the older Darwinian notion of natural selection, but that the two operate in different domains." (Eldredge, 2001, p. 67)
"Mendelian particulate inheritance (today, we call the "particles" genes) was originally identified with De Vries's "mutation theory", according to which new variations or species originated in large jumps, or macromutations, and evolution was exclusively explained by mutation pressure. Darwinian naturalists, believing that Mendelism was synonymous with mutation theory, held on to theories of soft inheritance, while they considered selection a weak force at best. They did not know of the new findings in genetics that would have supported Darwinism. (SegerstrŒle, 2002)
Notice how, in every version of the story above, the position taken by early geneticists just doesn't make sense. This isn't a story of theory versus theory, its a story of confusion ultimately yielding to reason.
If de Vries and the other geneticists are playing the role of the pied piper in this story, the "naturalists" are like the children lured away from their Darwinian home. Ultimately the innocents are returned, and order restored, by (oddly enough) mathematicians:
"Between 1918 and 1932 Fisher, Haldane, and Wright showed that Mendelian genetics is consistent with natural selection. Only then, more than 60 years after the publication of The Origin of Species, was the genetic objection to natural selection finally removed. Modern molecular and developmental genetics have confirmed in exquisite chemical detail the key aspects of genetics necessary for Darwin's ideas to work: that the genetic material is DNA, that DNA has a sequence, . . . mutates . . . contains information . . " (p. 16 of Stearns and Hoekstra, 2005)
Anatomy of a Myth
In a subsequent post, we will look at original sources to see what the "mutationists" actually believed, and why. And eventually we will integrate this into the bigger picture of how evolutionary theory developed. But for now, lets just summarize the pattern that is apparent in the literature.
First, the mutationism story is clearly a story or myth, and not an ordinary scientific truth claim. We can see this because the story-tellers are not using ordinary scientific conventions to convince us that the story is true. If you or I were making an ordinary scientific argument (for instance) for an effect of "translational selection" on codon usage, we would mention a correlation between codon frequencies and the abundance of corresponding tRNAs, citing the classic work of Ikemura (1981), and we might even repeat a figure showing this correlation, to impress this point upon the minds of readers (e.g., just as in Ch. 7 of Freeman & Herron, 1998).
When I see instances of the mutationism story, typically I don't find quotations illustrating what the mutationists believed, nor facts & figures to refute their views, but only vague attributions and generalized claims. Apropos, the following quotation from Ernst Mayr never fails to make me laugh:
The genetic work of the last four decades has refuted mutationism (saltationism) so thoroughly that it is not necessary to repeat once more all the genetic evidence against it. (Mayr, 1960)
And the puissant Dr. Mayr proceeds on, not boring the reader with any tiresome "genetic evidence", nor citing sources that might allow the reader to evaluate the truth of his statement. Its a story, after all.
By contrast, the 3 sources that I mentioned above as providing scientific history, rather than myth, all make reference to specific experimental and theoretical results, and reveal knowledge of specific historically important scientific works. For instance, Strickberger's reference list includes Johannsen, 1903, as well as the 1902 paper by Yule that reconciled Mendelian genetics with quantitative variation (in neo-Darwinian mythology, credit for Yule's work is given to little Ronny Fisher, who was 11 at the time).
Second, every story has a plot or "action", and the main action of the mutationism story is a turn of fate in which power is temporarily in the hands of the wrong people or ideas. In archetypal terms, its a story of usurpation and restoration: the throne is usurped, and the kingdom falls into darkness and confusion until the throne is restored to the king's rightful heirs. The mutationism episode didn't have to be told that way: it might have been presented as a period of reform (in which old ideas were abandoned) or discovery (when new territory was mapped out). Instead, its presented as a mistake, an interlude of confusion, a collective delusion.
Indeed, another way to look at the mythic action is that the Mendelians are wizards or false prophets who place the kingdom under a spell, leading folks astray and causing them to believe things that they just shouldn't have believed.
What delusional spell did the Mendelians cast? In the story by Eldredge, or by Stearns & Hoekstra above, the spell is that Mendelian genetics is inconsistent with "the concept of natural selection" (Eldredge). In the story told by SegerstrŒle, Cronin, Mayr and The Economist, the delusional spell is a bit different: the principle of selection is irrelevant because mutational jumps alone explain evolution.
Third, the key to restoring Darwin's kingdom was to add the missing piece of genetics. Ultimately, after the period of darkness ended, the discovery of genetics "provided the missing link in Darwin's theory" (SegerstrŒle, 2002), or "The missing link in Darwin's argument was provided by Mendelian genetics" (Ayala & Fitch, 1997). Darwinism was restored, not by taking away the power of genetics, but by redirecting it to support Darwinism. Clearly, genetics is the key to ruling the kingdom, like the One Ring that Rules them All in Tolkien's world. The ones who have the ring have the power.
The story is made more fascinating by the fact that the key to power is literally a code of rules developed by a monk that remained lost for nearly half a century. The usurpers who discover The Monk's Code misinterpret it, and use it to overthrow the true king, establishing a reign of error. But when The Founders decipher the true meaning of the Monk's Code, The Architects campaign throughout the kingdom, spreading the news: the Monk's Code proves that Darwin is the true king. Darwin's rule is re-established, all opposition ceases, and the kingdom is unified.
Homework
If you would like to contribute a mutationism story, I would be happy to start a collection if you make it easy for me by providing a complete and well formed text item. Be sure to provide a quoted passage with a source, citing exact page numbers. If we get enough stories, lets try to recruit a sociologist or historian to study this further.
Summary
To summarize, the mutationism story is a myth that is retold in secondary sources. The basic story is simple: the discoverers of genetics misinterpreted their discovery, thinking it incompatible with Darwinism; Darwinism went into disfavor; population geneticists came along and showed that genetics was the missing key to Darwinism; Darwinism was restored and once again reigned supreme.
Next time on the The Curious Disconnect, we'll start pulling on some of the loose threads of this story.
For now, note how the writers quoted above are genuinely baffled by our scientific history. It just doesn't make sense to them. A century ago, most of an entire generation of scientists thought of genetics as a contradiction of Darwinism. This is a historical fact, and presumably it has an explanation that rational folks can understand by examining what scientists of the time wrote. But this historical fact mystifies Dawkins, Eldredge, Cronin, and others.
References
Anonymous. 2005. Ernst Mayr, evolutionary biologist, died on February 3rd, aged 100. The Economist, February.
Ayala, F. J., and W. M. Fitch. 1997. Genetics and the origin of species: an introduction. Proc Natl Acad Sci U S A 94:7691-7697.
Cronin, H. 1991. The Ant and the Peacock. Cambridge University Presss, Cambridge.
Dawkins, R. 1987. The Blind Watchmaker. W.W. Norton and Company, New York.
Eldredge, N. 2001. The Triumph of Evolution and the Failure of Creationism. W H Freeman & Co.
Freeman, S., and J. C. Herron. 1998. Evolutionary Analysis. Prentice-Hall, Upper Saddle River, New Jersey.
Gould, S. J. 2002. The Structure of Evolutionary Theory. Harvard University Press, Cambridge, Massachusetts.
Ikemura, T. 1981. Correlation between the abundance of Escherichia coli transfer RNAs and the occurrence of the respective codons in its protein genes: a proposal for a synonymous codon choice that is optimal for the E. coli translational system. J Mol Biol 151:389-409.
Mayr, E. 1960. The Emergence of Evolutionary Novelties. Pp. 349-380 in S. Tax, and C. Callender, eds. Evolution After Darwin: The University of Chicago Centennial. University of Chicago Press, Chicago.
SegerstrŒle, U. 2002. Neo-Darwinism. Pp. 807-810 inM. Pagel, ed. Encyclopedia of Evolution. Oxford University Press, New York.
Stearns, S. C., and R. F. Hoekstra. 2005. Evolution: an introduction. Oxford University Press, New York.
Strickberger, M.W. 1990. Evolution (1st edition).
Notes
1 The defining characteristic of a myth is not that it isn't literally true, but that it isn't told for reason of being literally true, but for reason of being meaningful or poignant: a myth is a story with a cultural value, not necessarily a literal-truth value. The connection between myths and untruths, then, has to do with discoverability: when we find a pattern P = { X people are repeating story Y }, where X is a large number, this pattern by itself does not prove that Y is a myth because X people might have all discovered or verified Y independently; but if Y has diverse elements that are untrue (or unverifiable), then we can conclude that its repetition does not signify independent verification, suggesting that its a myth.
2The Oxford Encyclopedia of Evolution does not have an article on mutationism; the article on Morgan says nothing of his views on evolution; there is no article on Bateson; mutationism is only addressed peripherally in Hull's article on the history of evolutionary theory; it is mainly addressed in SegerstrŒle's article on neo-Darwinism.
8 comments :
This is interesting because it establishes the existence of this myth, but I'm curious about real evidence as to what the mutationists believed. I was under the impression that at least in Darwin's own lifetime there existed people who actually believed what the myth says mutationists believed. I seem to remember reading Darwin criticizing macromutationism on the grounds that it is so improbable as to be a miracle claim, so unless he was making shit up there must be some truth to the story. But of course that's what myths are built on.
A very similar case (of Modern Synthesis mythology) occurs when people talk about Fleeming Jenkin, whose objection to natural selection (assuming blending inheritance, new variants would blend with the common phenotype and thus wouldn't be significantly perpetuated) supposedly stumped Darwin and his fans up until the Synthesis. This turns out to be totally wrong, as can be seen if you look at what Jenkin wrote and at Darwin's correspondence and his comments in subsequent editions of the Origin. But it suggests that there is something about the Modern Synthesis that was conducive to reinterpreting past controversies to make MS look great.
I'm intrigued by your evolving series of posts but utterly baffled at this point regarding where you intend to take us. Is your beef with the historians of science or scientists (e.g., Mayr) themselves, or will you lead into a campaign to resurrect the notion of mutational bias as a mechanism of evolutionary change? I suspect it is the latter, a suspicion based both on your own published work and in the preceding post in this series, but for those late to the game (and even to this reader who was happy to see a second post from an old friend-- think Iowa, Joes Place)), the present screed offers no guidance.
Larry, is there any way you could tag these posts as "The Curious Disconnect" or something else distinctive? Would greatly help with the searching + referencing! Thanks =D
"The defining characteristic of a myth is not that it isn't literally true, but that it isn't told for reason of being literally true, but for reason of being meaningful or poignant"
Sure? There are lots of things written about "evolution myths" and "science myths", and the word always mean a false belief held by many. There are also titles like "The Myth of Evolution", "The Myth of Darwinism" etc.
I have just checked the meaning of "myth" in several English dictionaries and, well... it means commonly a false belief. That "defining characteristic" of being "meaningful or poignant" is difficult to find. I think that the use of the word "myth" in these contexts is purely a sophism. We don't like how a science issue is being explained or popularized, and then we call it a "myth".
So, where is the "mutationism myth"? We'll find it in the secnd part of the Mutationism Myth, I suppose...
Alexander says,
... it suggests that there is something about the Modern Synthesis that was conducive to reinterpreting past controversies to make MS look great.
Bingo! Give the man a prize.
This is the point that Gould made in The Return of the Hopeful Monster where he defended some of the views of Richard Goldschmidt.
Gould said,
I want to argue that defenders of the synthetic theory made a caricature of Goldschmidt's ideas in establishing their whipping boy.
They did the same with mutationism in order to purify the modern synthesis and make it seem very simple.
"The neo-Darwinian theory of the geneticists is no longer tenable"
This is Goldschmidt himself. It's difficult not caricaturize his ideas a bit ;o)
Thanks to you all for the comments posted while I was on vacation.
Anonymous, as stated in the introduction, my main focus is on clarifying theoretical problems, not "campaigning" for a particular view of how evolution works in reality. So, I'm not necessarily trying to lead you somewhere in that sense. If you were waiting for me to propose "neo-Mutationism" as "the Next Synthesis" (or something like that), you are going to be disappointed. At the end of dissecting the Mutationism Myth, we will have achieved a deeper understanding of two major issues in evolutionary thinking, one of which is how to think about the role of variation in evolution, and the other of which is the problematic reinvention of "Darwinism".
Paleofreak, I'm not exactly blown away by your research skills, nor by the guilt-by-association argument linking me with creationists who have used the word "myth". In the future, please try harder, or write less. Scholarly usage of "myth" or "mythology" (which is a topic of study for cultural anthropologists) clearly corresponds to the kind of explanation that I gave, in which the truth or falsity of a story is not the key to its mythic status. To quote wikipedia on myth,
"The term 'myth' is often used colloquially to refer to a false story; however, the academic use of the term generally does not pass judgment on its truth or falsity."
If you are not accustomed to scholarly writing and "myth" leaves a bad taste in your mouth, then feel free to substitute "legend" or "story". Whatever the terminology, the point is that the mutationism { myth, tale, legend, story }, like an urban legend, is re-told uncritically. It is the pattern of re-telling, rather than anything else, that makes a verbal construction a myth.
And yes, specific elements of the mutationism myth, duly illustrated in passages that I quoted already, will be shown to be largely false.
Thank you, Arlin, for your explanation. You are using an scholarly usage of "Myth". OK.
I don't deny that usage. The Myth of Eternal Return, for example; The universe is supposed to recur infinite times; true or false? that's not the point! I think I understand.
But, sorry, it seems to me that even in scholar works, the term "myth" is used a lot of times with the meaning of "false", larguely "wrong" belief, uncritically -your word- held and repeated. Except, of course, when they talk about the myths of... Mythology -discussing their falsehood would be time-wasting.
Also, I didn't mean to associate you with the creationists in any sense! So, if "The Myth of Evolution" example er... leaves a bad taste in your mouth, you can replace it with The Myth of Creationism. Or with The Myth of the Noble Savage, The Myth of Man the Killer, The Myth of Cultural Homogenization, the Myth of Western Superiority, The Myth of Black inferiority, The Myth of Matriarchy, The Myth of Monogamy, The Myth of Primitive Societies, The Myth of Postmodern University, The Bonobo Myth, Etc.
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