U pon reading Daniel Boorstin’s The Discoverers many years ago, I became fascinated with the ebbs and flows of human achievement, and especially those points in world history that have been associated with a flowering of great accomplishment. The most famous are Athens in the Periclean age and Florence in the Renaissance, but there have been many other less spectacular examples. Sometimes, the surge of great creativity is most obvious in a particular domain—literature in nineteenth-century Russia, for example—but strides made in one field are usually accompanied by strides made in others. Historically speaking, what accounts for the difference in the fertility of the cultural ground?

In the late 1990s, I set out to assemble databases of humanity’s great achievements, applying historiometric methods to identify the significant figures and remarkable achievements. The result was a book I published in 2004,...