"Why We Don’t Marry" by James Q. Wilson, in City Journal (Winter 2002), Manhattan Inst., 57 Vanderbilt Ave., New York, N.Y. 10017.

Despite the apparent stabilization of some social trends, one in five white children, and more than one in two black children, are born out of wedlock. Many critics blame "the ’60s" for starting the trend, but Wilson, the noted social scientist and emeritus professor at the University of California, Los Angeles, points to an earlier decade—the 1920s—and roots that stretch back to the 18th century and the Enlightenment.

It is in the nations "where the Enlightenment had its greatest effect"—Australia, Britain, Canada, France, the Netherlands, and the United States—that families with an absent father are most common today, he points out. "It was in the enlightened nations that nuclear rather than extended families became common, that individual consent and not clan control was the basis of a marriage contract, and that divorce first became legal."

By enthroning human reason and discarding many ancient rules, the Enlightenment "gave us science, technology, freedom, and capitalism," says Wilson—but also over time undermined old beliefs. "Whereas marriage was once thought to be about a social union, it is now about personal preferences. Formerly, law and opinion enforced the desirability of marriage without asking what went on in that union; today, law and opinion enforce the desirability of personal happiness without worrying much about maintaining a formal relationship."

The change was slow and almost unnoticed, Wilson says. "The most important Enlightenment thinkers assumed marriage and denounced divorce." But things changed. By the late 19th century, the notion that the public should support needy children whose mothers were widowed was winning acceptance, and slowly over the decades ahead the circle of "needy" fatherless children was broadened.

Meanwhile, the movement for the legal emancipation of women was gaining force. Nineteenth-century women "could not easily own property, file for a divorce, or conduct their own affairs. By the 1920s most of these restrictions had ended." Affluence and freedom proved a heady mix. The 1920s produced "an enthusiastic display of unchaperoned dating, provocative dress, and exhibitionist behavior. Had it not been for a time-out imposed by the Great Depression and the Second World War, we would no longer be referring to the ’60s as an era of self-indulgence; we would be talking about the legacy of the ’20s."

The ’60s just "reinstated trends" begun earlier in the century, "but now without effective opposition." Affluent, upper-middle-class people reshaped the culture, with the poor paying the price. For example: "People who practiced contraception endorsed loose sexuality in writing and movies; the poor practiced loose sexuality without contraception."

These deep-rooted cultural changes are not easy to reverse, notes Wilson, and many, such as the advances in women’s rights, should not be. Americans aren’t even likely to accept tougher divorce laws. Still, the fact that Americans continue to get married and hope their children will too encourages Wilson. If marriage is to regain its former stature, it will not be through government policies, but "from the bottom up by personal decisions."