Not only would working longer keep people healthier and happier, it would ease the strain on Social Security and Medicare, boost our sagging economy, and improve the standards of living of millions of Americans. We’re not talking about octogenarians hanging in there, just about adding a few more years to the current average retirement age (63 for men, 62 for women). Yet widespread ageism across the job spectrum makes this scenario unlikely.

Maybe we think it’s like teeth: if the first ones don’t fall out on schedule, there’s no room for the second set. Or like the forest canopy: there’s only so much sunlight and an awful lot of leaves. Is the number of good jobs fixed? Do all ages compete for them?

“The people of early America exalted old age; their descendants have made a cult of youth.” That history, and its social consequences, is the subject of David Hackett Fischer’s terrific book, Growing Old in America. It’s always seemed a bum deal that aging Americans face a double whammy: physical decay coupled with social invisibility.