The evolution of evolution.
You can accept or reject these particular evolutionary explanations as you like. But the underlying message is worth taking home: Much of what now passes for "natural selection" isn't exactly natural. It's social. As such, it deserves no presumptive respect as a validator or promulgator of objective fitness. Nor does the discovery of a genetic basis for this or that trait prove it's more than a social construct. In the era of cultural selection, many genes are a social construct. Which makes them no less real.
All of which poses a problem for anyone who equates genes with human nature, or who expects evolution to take God's place as judge and perfecter of humankind. It may be true that today's God a human creation. But so, in a way, is today's evolution.
Will Saletan covers science, technology, and politics for Slate and says a lot of things that get him in trouble.
Photograph of a monkey on Slate's home page by Peter Macdiarmid/Getty Images.