I would wager that if an average citizen from Athens of 1000 BC were to appear suddenly among us, he or she would be among the brightest and most intellectually alive of our colleagues and companions, with a good memory, a broad range of ideas, and a clear-sighted view of important issues. So Stanford geneticist Gerald R. Crabtree begins back-to-back Forum pieces for Trends in Genetics, entitled “Our Fragile Intellect” (Parts I and II). Crabtree’s thesis: humanity is “almost certainly” losing its superior intellectual and emotional capacities. Crabtree doesn’t seem to be arguing for the intellectual vibrancy of the...