MachineMachine /stream

A few years ago Tufts philosopher Daniel Dennett opined that the idea of natural selection - proposed 150 years ago in Charles Darwin's "On the Origin of Species" - was "the best idea anybody ever had." The flood of books published this year to celebrate the sesquicentennial would seem to prove Dennett right.

The "idea of natural selection" is that changes in any organism's makeup or behavior will persist or not according to whether they make it more or less likely for that organism and its descendants to survive. What kind of changes, and where do they come from? Any kind, from anywhere. Chemical accidents or cosmic radiation may alter an organism's genes, and therefore its physiology, for better or worse. Environmental change or social interaction may make one physical or behavioral trait more advantageous than another - meaning that those who inherit or learn that trait will survive and reproduce more abundantly. This is "Darwin's dangerous idea," from which all of evolutionary bio