Bryan Caplan has the knack to think where no one dared to think before - he can think the unthinkable. I knew only one other person who could do it: Edward Teller. The New York Times article on humanity's falling fertility is resonating strongly along the corridors of the blogosphere and Bryan brought up a scenario no one before has explored seriously: What if fertility falls to ... nothing? It appears that even the pessimistic projections of international organizations are in fact... optimistic. Let me quote him:
Now notice: The most obvious projection - one in which the decline in CD purchases (Caplanspeak for babies) continues - is conspicuously absent! And at least for CDs, isn't that the most reasonable projection? CD sales per person will fall to near-zero, and the world stock of CDs will slowly do the same.The illustration shows the San Francisco Corps of Ballet representing the explosion of Trinity.
Are people like CDs? At least for the near-term, there's every reason to think so. If fertility has been declining for decades, it's strange to assume that fertility coincidentally bottom out yesterday. So Constant-Fertility Projections are actually probably on the high side.
In the longer-run, though, evolution will almost surely save us (J says: Note the royal "us". Caplan believes he is surely among the saved. But few assimilated Jews will be. Sorry.) If the average woman has one child, population size shrinks by 50% per generation. But if 10% of women have three kids, and if family size (like virtually every trait) is partly heritable, the proportion of the population that wants 3 kids will exceed 50% in a few generations. In a century or two the desolate villages of Italy will be reclaimed by the descendants of those of us who think that life is a chain worth continuing.