* This is a special mini-Problematica. Let’s call it Part 2.5 of my two-part essay on the origin of novel characters. (Here are Parts 1 and 2.) Problematica is written by Max Dresow…
Have you ever had the experience of learning about something and then— all of a sudden— seeing it everywhere? The phenomenon apparently has a name: the “Baader-Meinhof” illusion, in reference to a West German militant communist group. A St. Paul resident, Terry Mullen, coined the term in a letter to my local newspaper, the St. Paul Pioneer Press. After learning about the Baader-Meinhof Gang, Mr. Mullen began noticing it everywhere. A sort of domino theory for the world of memes. Or, if you prefer, here’s Lewis Black:
The guy next door to you says, “Have you heard? There’s a bear that’s shitting everywhere!” And you say, “That’s ridiculous.” And the next day the bear is following you around.
I had a Baader-Meinhof experience yesterday. My personal shitting bear was Mivart’s dilemma— not something I just learned about, but something I just wrote about. Here’s what happened. While stealing a moment of peace outside my toddler’s room, I pulled a book from my bookshelf. It was an essay collection called Possible Worlds by J. B. S. Haldane (1927). One essay was titled “Darwinism to-day,” the same title as Vernon Kellogg’s 1907 book, which I wrote about in my last post. I began to read. It started with a Haldane staple— using biology to ridicule the argument from design:
On average, every vertebrate harbours some dozens of parasitic worms, whose remote ancestors were free-living. Blake asked somewhat doubtfully of the tiger: ‘Did he who made the lamb make thee?’ The same question applies with equal force to the tapeworm, and an affirmative answer would clearly postulate a creator whose sense of values would not commend him to the admiration of humanity. (Haldane 1927, 29)*
[* Everyone has heard the story about Haldane and the theologian. The theologian asks Haldane what a biologist can deduce about the Creator from a knowledge of his works. Haldane replies that He must have “an inordinate fondness for beetles.” The story, alas, is too good to be true. Stephen Jay Gould tracked down the real story in an essay, “A special fondness for beetles,” reprinted in Dinosaur in a Haystack (1995).]
J. B. S. Haldane (left) looking fly in stripes
Now, there’s nothing very Baader-Meinhof-y about that. But consider this. Several pages after the passage just quoted, Haldane considers some objections to the theory of natural selection. The first is that “a change of character will only be of advantage to a species if some other varies simulataneously in the same direction” (37). Ridley (1982) calls this the problem of coadaptation. Haldane dispatches it by noting that many genes have effects on more than one structure— they are pleiotropic in the parlance. “A more serious objection,” he continues, “is that rudimentary characters sometimes appear which can be of no use to their owners, but only become so on further development some thousands of years later” (40). This is Mivart’s dilemma and it is “at first sight fatal to the selection hypothesis.” (Mivart’s dilemma was a big deal!) The objection, however, “can be met along several lines.” Haldane discusses just one:
A change in one organ, as Darwin pointed out, generally carries with it a change in others. Hence an increase in the complexity of one molar brought about by natural selection may cause the beginning of a new cusp in its neighbour. This cusp will at first be useless, but as it increases selection will begin to act on it also, so that the process will gain momentum until we arrive at the extremely complex grinders of the elephant or horse. Moreover, we can trace just the same gradual beginnings of apparently quite useless organs, the excessive skeletal outgrowths which have been the harbingers of extinction in many animal groups, both vertebrate and invertebrate. (Haldane 1927, 40)
The last is a somewhat confusing sentence, but Haldane seems to mean that the problem of incipient structures and the phenomenon of over-development can be explained in the same way: through what Darwin calls “correlations of growth.” He continues:
If we knew more about these creatures’ soft parts we could perhaps elucidate these problems. Some light is thrown on them by recent work of J. S. Huxley and others. They have shown that, in certain animals, growth of the whole body leads to disproportionate growth of one part. Thus in a group of crabs, whenever the body doubles in weight, the large claw increases three times, until it finally becomes almost as large as the rest of the animal. Any cause promoting growth of the whole body, therefore, leads to a disproportionate growth of the claw. And such a cause is to be found in competition within the species, more especially the competition between males for females by fighting, as is common among mammals, rather than display, as seems to be the custom with many birds. (Haldane 1927, 41)
A fiddler crab whose big claw scales allometrically with body size (as its body grows, its claw grow proportionately larger: this is called “positive allometry”)
Haldane concludes the discussion by observing that “no satisfactory cause of evolution other than the action of natural selection on fortuitous variations has ever been put forward” (Haldane 1927, 43). “It is by no means clear that natural selection will explain all the facts. [Haldane is especially worried about the origin of interspecific sterility, this being 1927.] But the other suggested causes are unverified hypotheses, while selection can be observed by those who take sufficient trouble.”
Say, have you heard about that bear?
References
Haldane, J. B. S. 1927. Possible Worlds and Other Essays. London: Chatto and Windus.
Ridley, M. 1982. Coadaptation and the inadequacy of natural selection. The British Journal for the History of Science 15:45–68.
Also, here is a video of John Maynard Smith talking about Haldane’s “last words.” (They weren’t actually his last words: just something he said before a major surgery. Just watch the video.)