in the absence of clan feeling, the nuclear family—we four—become ever more important as a kind of life raft in the ocean of existence. Perhaps too important. Upper-middle-class people overinvest in one or two kids rather than broadly investing in many generations, as most human beings throughout time have done, and this overinvestment, a frequent argument goes, is hugely destructive to society at large, since it makes them ferociously desperate to reserve the same places for their kids that they have been occupying, leaving no room for others to join in or up.
