The Aukward Truth

Great auks. John Gerrard Keulemans via Wikimedia Commons.

“Why Are There No Penguins at the North Pole?”—a February 6, 2015, article in the Vatican newspaper L’Osservatore Romano by Carlo Maria Polvani, a biochemist-turned-priest working in the Vatican’s Secretariat of State—raises a good question, although in the service of a bad agenda. The agenda isn’t creationism: Polvani correctly describes evolution as “shared by the majority of the scientific community” and moreover cites Pope John Paul II’s 1996 Message to the Pontifical Academy of Sciences as sufficient to show that “few today doubt the evolution of life on Earth.” Rather, the agenda is opposition to “Darwinism,” which he defines as holding that there are “two, and only two, forces to explain the phenomenon of evolution,” namely chance, “which creates diversity at the genotypic level,” and selection, “which supports the emergence of the phenotypes most likely to guarantee survival.”

It’s unclear that anyone accepts Darwinism as Polvani defines it, Darwin not excepted. Although there’s a degree of variation, the average biology textbook is likely to identify not two but four major processes at work in evolution—mutation, migration, drift, and selection—and perhaps a handful of further processes such as endosymbiosis and horizontal gene transfer. In his article, however, Polvani quickly slides from chance and selection to chance and necessity, citing the Nobel Prize-winning biologist Jacques Monod’s classic Chance and Necessity (Le Hasard et la Nécessité, 1970) en route. In so doing, however, he is tacitly moving from a scientific question, that of whether mutation and variation are all the natural processes that are at work in evolution, to a philosophical question, that of in effect whether natural processes are all the processes that are at work in evolution.

In consequence of the slide, the article fails to advance a cogent argument. For example, consider Polvani’s insistence that “it is…fair to ask whether there exists an experiment capable of contesting the postulate that chance and necessity are the only forces at play in the origin and selection of species.” Leaving aside the mistaken assumption that only experimental data could be relevant, it is only fair to ask, in return, what he means by chance and necessity. If “chance and necessity” means mutation and selection, as he suggested originally, then the answer to his question is yes, in light of the evidence for the existence of drift and migration as evolutionary processes. If, however, “chance and necessity” is code for “any natural process whatsoever,” then the answer to his question is no, in light of the inability of science to assess untestable hypotheses about supernatural intervention in or guidance of evolution.

What about those penguins, though? Polvani invokes the waddling seabirds in order to argue that Darwinism is unfalsifiable. Given the evolution of penguins in Antarctica, he argues, Darwinism “implies that in the Arctic zones, similar in many ways to those of the Antarctic, species similar to the penguin might have been expected. Instead there are none.” Showing that their adherence to their position is dogmatic rather than scientific, Darwinists refuse to acknowledge the falsification, instead invoking ad hoc explanations like “the presence of polar bears” in the Arctic. By the same token, Polvani also criticizes Darwinism for its lack of predictive power: “Indeed, there is not a single biologist who can forecast if and when penguins might appear at the North Pole, not even assuming the hypothetical extinction of polar bears due to global warming.” Hence he calls for a paradigmatic change.

There’s a lot wrong here, more than I can do justice to in a short blog post. With respect to falsifiability, Polvani fails to explain how Darwinism as he defines it—“chance and necessity”—is supposed to predict the existence, or even the probability, of penguins in the Arctic, and why that’s a prediction distinctive to it. With respect to predictability, he makes no mention of the striking predictive successes of modern evolutionary biology, such as the discovery of the “fishapod” Tiktaalik in the Canadian Arctic or the identification of the eusocial mammal Heterocephalus glaber. Moreover, if it’s a weakness of evolutionary biology that it fails to predict the arrival of penguins at the North Pole, why isn’t it also a weakness of, say, quantum mechanics? And exactly what paradigm is Polvani urging that biologists adopt to replace evolution, anyway? Surely not creationism, which Pope Francis recently derided as a form of magical thinking.

But if you think that such philosophical concerns are for the birds, let’s turn instead to ornithology. Polvani is fond of the penguin (which he speaks of as a single species: there is actually a clutch of different penguin species, extant and extinct), but it is instructive to consider the auk. The great auk (now extinct) was the original penguin—its scientific name is Pinguinus impennis—and the Sphenisciformes, of which European scientists learned later, take their common name from their resemblance to the great auk. Josh Rosenau, like me a fan of Patrick O’Brian’s Aubrey/Maturin novels, reminds me of the following exchange between Stephen Maturin and a sailor originally from Canada, in The Surgeon’s Mate (1981):

There were always birds, particular birds, on the Banks, thick or clear.

“What kind of birds?” asked Stephen.

“Murres, dovekies, guillemots, razorbills, kittiwakes, sheerwaters, fulmars, skuas, all sorts of gulls, puffins, penguins—”

“Penguins, my dear sir?” cried Stephen.

“That’s right, Doctor. A very old-fashioned bird, that can’t fly but only swim. Some call them garefowl, but we call them penguins. It stands to reason, if a bird can’t fly, it is a penguin: ask any whaler that has been far south.”

The sailor’s etymology is backwards: great auks aren’t called penguins because they resemble penguins; penguins are called penguins because they resemble great auks. But the resemblance is the key point. Penguins are related to petrels and auks are related to gulls, so although they’re both social seabirds well-adapted for life in the water, those similarities are shared as a result of convergent evolution. Auks, indeed, are often called the penguins of the north. The great auk, like penguins, was moreover flightless, again as a result of convergent evolution. So the key argument in Polvani’s article, which even provided its title, is premised on a false zoological claim: for all practical purposes, there are (or were) penguins in the Arctic. Aukward!