SNIP Sarah Bernhardt and Franz Kafka; Albert Einstein and Rosalind Franklin; Benjamin Disraeli and (sigh) Karl Marx — how is it that a people who never amounted even to one-third of 1 percent of the world’s population contributed so seminally to so many of its most pathbreaking ideas and innovations? The common answer is that Jews are, or tend to be, smart. When it comes to Ashkenazi Jews, it’s true. “Ashkenazi Jews have the highest average I.Q. of any ethnic group for which there are reliable data,” noted one 2005 paper. “During the 20th century, they made up about 3...