Exactly 20 years ago, I wrote an article for Scientific American that, in draft form, had the headline above. My editor nixed it, so we went with something less dramatic: "In the Beginning…: Scientists are having a hard time agreeing on when, where and—most important—how life first emerged on the earth." That editor is gone now, so I get to use my old headline, which is even more apt today. Dennis Overbye just wrote a status report for The New York Times on research into life's origin, based on a conference on the topic at Arizona State University. Geologists, chemists,...