Arguing Darwin

An exacting essay by Michael Ruse on the general ignorance of science among anti-Darwinists:

But rather than work over the details, I want to draw attention to the way this crop of critics ignores evolutionary biology—aside from the kind of cherry-picking in which Fodor engages. Nagel may sneer about the failure to find “accessible literature” that answers his worries. In what part of the library was he doing his literature search? Where, for example, is any discussion of the Grants’ work on the Galápagos finches? What about a detailed look at the new scholarship that is challenging earlier thinking about the evolution of bipedalism? What about the discoveries of molecular biology and of the similarities (homologies) between humans and fruit flies? And why no mention of Marc Hauser and his work uncovering the secrets of moral thinking? There is a deafening silence on those and other issues. Fodor, Nagel, and Plantinga don’t need to turn themselves into biochemists, but some awareness of the issues and advances would not be entirely misplaced.

This total lack of interest in the science is surely suggestive. The critics are being driven by other, for them deeper, concerns. And as an evolutionist, I turn to the past for clues. What fueled the initial opposition to Darwin was a concern with our species, with Homo sapiens. For 150 years, since the Origin, critics have feared that we humans might become part of the evolutionary picture—not just our bodies, but our minds, our very souls. What makes us distinctively and uniquely human? This worry is still alive and well in today’s philosophical community. Plantinga is open in his fear that Darwinism makes impossible the guaranteed existence of our species. More, for years he has argued that Darwinism is bound up with the metaphysical belief that everything is natural (as opposed to supernatural), and that this leads to a collapse of rational belief and knowledge. The chance elements in Darwinism are simply not compatible with Plantinga’s Christian faith.

If you are going to be a philosopher or ethicist commenting on scientific issues you must be reading the literature of science. One can’t critique Darwin if one doesn’t understand how the eye evolved. Philosophy needs to get over its fear of empirical data.

The Hoatzin Is Weird

The first time I saw a hoatzin I was 8. It was in an issue of Kid’s Discover and I could never remember the name but I remembered the claws and those big eyes. Let David Attenborough tell you more:

via Reddit

Cultural Selection

Don’t you love it when something you’ve been harping on is supported by hard evidence? Biologists are discovering that culture is affecting evolution at the genetic level:

The best evidence available to Dr. Boyd and Dr. Richerson for culture being a selective force was the lactose tolerance found in many northern Europeans. Most people switch off the gene that digests the lactose in milk shortly after they are weaned, but in northern Europeans — the descendants of an ancient cattle-rearing culture that emerged in the region some 6,000 years ago — the gene is kept switched on in adulthood.

Lactose tolerance is now well recognized as a case in which a cultural practice — drinking raw milk — has caused an evolutionary change in the human genome. Presumably the extra nutrition was of such great advantage that adults able to digest milk left more surviving offspring, and the genetic change swept through the population.

This instance of gene-culture interaction turns out to be far from unique. In the last few years, biologists have been able to scan the whole human genome for the signatures of genes undergoing selection. Such a signature is formed when one version of a gene becomes more common than other versions because its owners are leaving more surviving offspring. From the evidence of the scans, up to 10 percent of the genome — some 2,000 genes — shows signs of being under selective pressure.

And the working definition of “culture” in this article is “broadly defined as any learned behavior, including technology.”

The Problem With Evolution

Is that a lot of stuff gets dragged along for the ride whether we want it to or not. A recent article in the Wall Street Journal discusses the problems of modernity are often due to traits that were highly beneficial when we were nomadic mastodon hunters. Our environment changed without requiring our bodies to do so:

[For example] the human mouth has also evolved unevenly. Teeth shrank considerably as agriculture changed our ancestors’ diets from mostly meat and plants to mostly carbohydrates. The human jaw shrank even faster, making wisdom teeth largely useless and creating the overcrowding that people face today.

Why haven’t years of evolution corrected these quirks? “Many features of our anatomy operate ‘under the radar’ of natural selection,” says Dr. Held. That is, they generally aren’t problematic enough to affect people’s survival before they reach reproductive age, so they keep getting passed on. Some experts think that wisdom teeth and the appendix may be slowly on their way out—some people are already born without them—since they do sometimes cause life-threatening infections.

And yet we treat many of these complications routinely, removing wisdom teeth and appendixes that show signs of causing trouble. So is that an enhancement or therapeutic?