Last night I saw a fascinating documentary on linguist Dan Everett's work with the Piraha language of the Amazon rainforest. The major, most controversial aspect of his work is his assertion that certain feature of language seem to be culturally created as opposed to biologicallly hardwired into human beings. This goes against Noam Chomsky's claims that there exists a universal grammar, an inherent logic to any language. If you're interested in learning more about Everett and the controversy in general, here is a good treatment from the New Yorker.
As for me, I am most impressed by Everett's truly scientific attitude and approach to life. Unlike most people (including scientists, who are often just as irrational and subjective as anyone else), Everett seems really committed to studying the truth and accepting what the evidence tells him. In the face of the Piraha Indians' indifference to the Bible and their joyous way of living life, Everett concluded that they didn't need to be saved, because they weren't deficient or flawed in the Christian sense of the terms. The missionary-turned-researcher eventually became an atheist himself, convinced by the Piraha approach to life. Likewise, Everett went from being a Chomskyan linguist to questioning the very basis of Chomsky's theories. Again, when he found evidence that went against his prior understanding or dogmas, Everett accepted the evidence and changed his thinking. This is rare and admirable.