People who know a lot about a lot have long been an exclusive club, but now they are an endangered species.
“Like a kingdom divided, which rushes to its doom, the mind that engages in subjects of too great variety becomes confused and weakened.” Leonardo da Vinci
Polymaths were the product of a particular time, when great learning was a mark of distinction and few people had money and leisure. Their moment has passed, like great houses or the horse-drawn carriage. The world may well be a better place for the specialisation that has come along instead. The pity is that progress has to come at a price. Civilisation has put up fences that people can no longer leap across; a certain type of mind is worth less. The choices modern life imposes are duller, more cramped.
The question is whether their loss has affected the course of human thought. Polymaths possess something that monomaths do not. Time and again, innovations come from a fresh eye or from another discipline. Most scientists devote their careers to solving the everyday problems in their specialism. Everyone knows what they are and it takes ingenuity and perseverance to crack them. But breakthroughs—the sort of idea that opens up whole sets of new problems—often come from other fields. The work in the early 20th century that showed how nerves work and, later, how DNA is structured originally came from a marriage of physics and biology. Today, Einstein’s old employer, the Institute for Advanced Study at Princeton, is laid out especially so that different disciplines rub shoulders. I suspect that it is a poor substitute.