Today, a nation dismayed by inequality and the intergenerational transmission of poverty must face the truth that political scientist Lawrence Mead enunciated nearly 25 years ago: “The inequalities that stem from the workplace are now trivial in comparison to those stemming from family structure. What matters for success is less whether your father was rich or poor than whether you knew your father at all.”

Moynihan, undaunted by his shrill critics who stifled debate and research, brought his barbed wit to the subject, suggesting that an important determinant of the quality of American schools was their proximity to the Canadian border. That is, high cognitive outputs, measured by standardized tests, correlate less with high per-pupil expenditure than with a high percentage of two-parent families, which are not scattered randomly.

The election of Kennedy was celebrated in academia as the empowerment of the professoriate. Moynihan ruefully remembered the euphoric expectation of “the direct transmission of social science into governmental policy.” We still are far from fully fathoming all that has caused the social regression about which Moynihan was prescient. There has been what he called “iatrogenic government,” an iatrogenic ailment being one caused by a physician or medicine: Some welfare policies provided perverse incentives for absent fathers. But the longer Moynihan lived, the more he believed that culture controls more than incentives do.