Hopeful Monsters and Other Tales: Evolutionists Challenge Darwin
Two recent articles show that Darwin is not invincible. On one side he is being attacked by hopeful monsters. On the other, he is being attacked by an atheist truth-seeker. Neither of these attacks are coming from creationists.
- Return of the hopeful monster: Tanguy Chouard raised eyebrows in Nature News with a headline that sounds like a new movie: “Revenge of the hopeful monster.” It discusses the revival of a heresy that would have ruffled Darwin, who always said, “Natura non facit saltum” (nature does not take leaps). Chouard discusses evidence that nature does take leaps – big changes that can occur within a single generation. “Experimental evidence has shown that individual genetic changes can have vast effects on an organism without dooming it to the evolutionary rubbish heap,” he said. (The evolutionary rubbish heap is presumably where winners of the Darwin Awards go.) But does the evolutionary Aesop fable give the edge to the gradualist tortoise, or to the saltationist hare? Maybe both.
Avoiding a complete overhaul of the Darwin evolution engine, Chouard tried to have his cake and eat it, too: “But small-effect mutations still matter – a lot. They provide essential fine-tuning and sometimes pave the way for explosive evolution to follow,” he explained. “As the molecular details unfold, theory badly needs to catch up.”
For evidence, Chouard exhibited an evolutionary pet, the stickleback fish. Offspring can vary substantially between armored and naked forms. This is due to a single gene location responsible for 2/3 of the spines. Chouard explained, “the reigning gradualist dogma regarded these as artificially protected monstrosities that would never survive the harsh hand of natural selection.” Gradualists have argued that pleiotropy (multiple effects of single changes) means that large changes would generally be deleterious. “How could a mutation in such a crucial gene result in anything but a hopeless monster?” A successful large change would be tantamount to a miracle.
The stickleback study, though, shows that “surgical strike” mutations that cause sudden changes in armor happen repeatedly. And Lenski’s multi-generational studies on E. coli showed both saltations and gradual mutations at work, producing increases in fitness by jumps and by small steps. The idea is “large-early, small-late” – big jumps that don’t kill the organism are fine-tuned by gradual changes. Some of the bacteria learned to digest citrate, and then these mutants quickly swept through and overtook the population. Lenski considered that comparable to the invasion of land by tetrapods. (For a different interpretation, see the Behe Blog.) “It remains to be seen,” though, Chouard added, “whether such elementary mechanisms of adaptation, often referred to as microevolution, can instruct the higher processes that constitute macroevolution, such as speciation and the emergence of biodiversity or complex organs.” Even Goldschmidt, the hopeful-monster champion, doubted leaps that large could be made. And Jerry Coyne cautioned generalizing results from asexual bacteria with small genomes and high mutation rates.
So is this disjunctive theory that says evolution proceeds both by leaps and by crawls an improvement on Darwin? Do the tortoise and the hare join hands and cross the finish line as a team? “Large effect or small, evolution begins to look like an endless list of special cases,….” Chouard admitted. “One reason is the general lack of knowledge about how changes in genes contribute to function and how this affects fitness.” That sounds a pretty basic requisite for understanding evolution. One evolutionist longed for a functional synthesis, “marrying evolutionary biology, molecular genetics and structural biology.” Some are glad for the return of Goldschmidt’s hopeful monster hypothesis; others favor a middle ground. “We need much more data before the issue of large versus small can be settled,” Coyne said, before the new studies can argue that “Darwin was wrong” about saltation.
The organisms are going to be the arbiters of this dispute. “A mutation may affect phenotype but not change fitness much,” Chouard ended. “It may have a large effect in the context of a given genome, or in a given environment, but may have a smaller effect later in an organism’s history.” So it seems way premature to claim that evolutionary biology has settled on a comprehensive theory of speciation, even 150 years after Darwin. Chouard handed out promissory notes: “As researchers drill down to the molecular mechanisms driving adaptation, theory may catch up and dogmas may recede.” Maybe Darwin was wrong. Maybe he was right. Maybe he was partly right. Who knows? He must be celebrated as the greatest biologist in history regardless.
- Dogma must go: Jerry Fodor, a philosopher at Rutgers, is angry at the dogmatic Darwinists who see natural selection as the be-all and end-all of evolutionary change. But he is no creationist; he is an avowed atheist. He discussed his book What Darwin Got Wrong, co-authored with Massimo Piattelli-Palmarini, an atheist professor of cognitive sciences at U of Arizona, on Salon.com. Thomas Rogers, who interviewed Fodor, was surprised that a published attack on Darwin did not come from the “religious right.” He said, “Their book details (in very technical language) how recent discoveries in genetics have thrown into question many of our perceived truths about natural selection, and why these have the potential to undermine much of what we know about evolution and biology.” For challenging Darwin, Fodor and Piattelli-Palmarini have received “obscene and debased ” comments on blogs.
Fodor’s beef with natural selection appears to stem from its storytelling propensity. Why do people have traits like hair on their heads and dark hair with dark eyes? “You can make up a story that explains why it was good to have those properties in the original environment of selection,” he said. “Do we have any reason to think that story is true? No.”
Fodor argues that there is no way to tell which traits were selected because they contribute to fitness, and which traits come along for the ride. “There isn’t anything in the Darwinist picture that allows you to answer that question.” Why do we have toenails? Do they serve an evolutionary purpose? How would we know? “It may be a case that in the environment there was some factor that favored toenails but there also may not.” This sounds like the Stuff Happens Law. Gene expression is too complicated, he said, to sort out fitness effects from random change: “Now the question is, how much of the evolutionary variance is determined by factors of the environment and how much is controlled by the organization of the organism, and the answer is nobody knows.”
Fodor even argues that picking out “traits” may be meaningless. A giraffe has a long neck. Did nature select that trait, or is it part of the giraffe package? “Animals can have long necks and toenails, but if you try to break such creatures apart into traits and you say, OK, ‘What selected this trait?’ and, ‘What selected that trait?’ you’ve made a mistake right from the beginning,” he said. “The disintegration of the organism into traits is itself a spurious undertaking.” Selection acts on the whole animal, he believes.
An example of the storytelling habit can be seen in last week’s Science paper on whale evolution.1 “The link between diatom diversity and observed cetacean diversity supports the hypothesis that diatom-based primary production has been an important driver of neocete evolution,” wrote Marx and Uhen. (A “neocete” is a modern whale.) How, exactly, did that environmental driver (diatom diversity and number) act on the genes of a pre-whale to make it a whale? It leaves the evolution of the complex structures of the customers assumed rather than explained. Undeterred, the authors next pulled a completely different explanatory tool off the shelf. “Similarly, the observation that climate change also has a role to play is not surprising in light of recent research that has demonstrated substantial temperature-dependent variations in the diversity of extant cetaceans.” But how can they disentangle that driver from other drivers, and explain why it acted the way it did on whales, but not on birds, mammals and everything else in the biosphere that was simultaneously subject to climate change? To take Fodor’s response, “Nobody knows.” Maybe Marx and Uhen should make a bold, Popperian prediction. Maybe they should predict what whales will evolve into after today’s anthropogenic climate change. Will it be as dramatic as turning a cow into a whale? Should we find it “not surprising” if climate change has a “role to play” in driving whales back onto land, or giving them wings? How would that role be measured?
Fodor knows his views could be perceived as traitorous. “I think there’s the sense that if you think that there’s something wrong with the theory you’re giving aid and comfort to intelligent design people. And people do feel very strongly about whether you want to do that.” He himself is unperturbed by that eventuality. “When you do science, you try to find the truth.”
1. Felix Marx and Mark Uhen, “Climate, Critters, and Cetaceans: Cenozoic Drivers of the Evolution of Modern Whales,” Science, 19 February 2010: Vol. 327. no. 5968, pp. 993-996, DOI: 10.1126/science.1185581.
Fodor’s courage for facing flak while seeking truth is admirable, but he doesn’t realize that his truth-seeking is incompatible with his atheism. Truth refers to ideas that are eternal – otherwise they are not true. How is an atheist, who is presumably a physicalist, going to employ concepts, ideas and propositions, which must be defended with honesty and integrity, without presupposing a moral and spiritual realm? A “force” will not do. Honesty, truth, integrity, morality presuppose a Person. The creationists, whom he accuses of post-hoc reasoning, actually have the pre-hoc conditions for intelligibility that give their post-hoc deductions meaning. Darwinists hawk their post-hoc stories without the pre-hoc, making them ad-hoc. That’s when the post-hoc fallacy ensues. Fodor should stop plagiarizing Judeo-Christian presuppositions and pay the price before taking part in the Judeo-Christian smorgasbord with its nutritious ingredients of rationality. So he should not worry about offending the other thieves, but make amends with the smorgasbord Owner.
It should be clear from these stories that criticisms of Darwin are not all religiously motivated. They are substantive. Darwinism is a collection of just-so stories funded by promissory notes with no empirical collateral. The bank that issues Darwin notes is bankrupt. Any theory that reduces to the Stuff Happens Law is dealing in worthless explanatory currency. If you call Chairman Charlie and ask, “What do you know?” he doesn’t answer. Let the dead bury their dead.