More from the "nature not nurture" camp:
Critics of new media sometimes use science itself to press their case, citing research that shows how “experience can change the brain.” But cognitive neuroscientists roll their eyes at such talk. Yes, every time we learn a fact or skill the wiring of the brain changes; it’s not as if the information is stored in the pancreas. But the existence of neural plasticity does not mean the brain is a blob of clay pounded into shape by experience.
Experience does not revamp the basic information-processing capacities of the brain. Speed-reading programs have long claimed to do just that, but the verdict was rendered by Woody Allen after he read “War and Peace” in one sitting: “It was about Russia.” Genuine multitasking, too, has been exposed as a myth, not just by laboratory studies but by the familiar sight of an S.U.V. undulating between lanes as the driver cuts deals on his cellphone.
Moreover, as the psychologists Christopher Chabris and Daniel Simons show in their new book “The Invisible Gorilla: And Other Ways Our Intuitions Deceive Us,” the effects of experience are highly specific to the experiences themselves. If you train people to do one thing (recognize shapes, solve math puzzles, find hidden words), they get better at doing that thing, but almost nothing else. Music doesn’t make you better at math, conjugating Latin doesn’t make you more logical, brain-training games don’t make you smarter. Accomplished people don’t bulk up their brains with intellectual calisthenics; they immerse themselves in their fields. Novelists read lots of novels, scientists read lots of science.
http://www.nytimes.com/2010/06/11/opinion/11Pinker.html
Democracy is the furthest extreme of "nurture": one man, one vote; we are all equal, politically and presumably, in the ability to make decisions.
Aristocracy is the furthest extreme of "nature": pick the best, let them dominate the rest, and hopefully, infuse those wretches with some improved genetic code.
When you think about it, the difference between thoughts and genetics is that the latter is tested and persists between generations. There is an inherent utility -- non-arbitrary -- in that.