Earlier this month I wrote two posts about the evolution of the eye, a classic example of complexity in nature. (Parts one and two.) I’d like to write now about another case study in complexity that has fascinated me for some time now, and one that has sparked a fascinating debate that has been playing out for over fifteen years. The subject is language, and how it evolved.

In 1990, Steven Pinker (now at Harvard) and Paul Bloom (now at Yale) published a paper called "Natural Selection and Natural Language." They laid out a powerful argument for language as being an adaptation produced by natural selection. In the 1980s some pretty prominent scientists, such as Stephen Jay Gould,