“If you seek his monument, look around you.”

That epitaph is carved on a stone in a quiet corner of St. Paul’s Cathedral, to honor the great English architect Christopher Wren.

And likewise, the monument to the great scholar James Q. Wilson can be seen by standing in New York City’s Times Square. The city life you see streaming all around you is as much James Q. Wilson’s achievement as that of any other human being. It was James Q. Wilson who, over a long career in intellectual and public life, (re)taught Americans how to keep their cities safe, and thus alive.

James Q. Wilson is perhaps most famous for his work (with George Kelling and Catherine Coles) of the “broken windows” theory of law enforcement.

The theory was based on a famous experiment in which two cars were abandoned on city streets. One car was in pristine condition; the other car had a window broken. The car with the broken window was almost instantly scavenged and vandalized. The other car was left alone.

Wilson, Kelling, and Coles drew powerful lessons from this experiment. In the 1960s and 1970s, law-enforcement had tended to shrug off minor urban disorder: street-corner drinking, graffiti. Those were years of rising crime, and law-enforcement officials thought it most rational to focus resources on the most dangerous offenses. The concentration of resources was both supported and excused by an academic leftism that depicted efforts to keep order in cities as the oppressive imposition of bourgeois morality on poor people not doing any real harm to anyone.

Wilson, Kelling, and Coles debunked these ideas. The disregard of petty disorder created an environment that invited major offenses. And a crackdown on minor offenses would ease the work of police in suppressing major crime.

These ideas were tested, first in Boston by chief of police William Bratton, then in the New York subway system, then finally on the streets of New York itself.

I remember one spectacular case.

A woman who owned a dry-cleaning store was knifed to death in the early morning hours on New York’s Upper East Side. The fingerprints on the knife were unrecognized. The crime threatened to go unsolved. Until New York police made one of their new sweeps to crack down on marijuana smoking and loitering in Washington Square Park in Greenwich Village. Previously, police had shrugged off the Washington Square scene: if ever there seemed a victimless crime, marijuana smoking in the park seemed to qualify. But when they arrested the marijuana smokers and fingerprinted them, they found a match to the fingerprints in the knifing.

People who break one law break many others. If the police enforce laws against subway-turnstile jumping, public drinking, and so on, they will catch the people who rob, knife, and shoot.

But “broken windows” was premised on an even more audacious idea: enforcing rules against petty disorder sends the message: the authorities are in control. The city is not only statistically safe; it looks and feels safe. Older people and women return to the streets. Shops open. Potential criminals feel eyes upon them. Potential victims cease to feel isolated and vulnerable and come to feel empowered and supported by the force of law.

The New York of Death Wish is transmuted into a New York where the greatest danger is the risk of being trampled to death in Times Square by the hordes of happy tourists.

“Broken windows” would seem a sufficient achievement for any one life. In the case of James Q. Wilson, however, that achievement flowed from a huge body of powerful social science work.

In two brilliant books, Thinking About Crime and Crime and Human Nature, Wilson countered the despairing fatalism of law enforcement in the 1960s and 1970s. He argued that it was not first necessary to solve all of society’s other ills — racism, unemployment — before reducing crime. He demonstrated that practicable changes in the behaviors of police and courts could powerfully alter the choices made by potential wrongdoers. If (as he hypothesized) a relatively small number of criminals committed relatively large amounts of crime, then holding those few criminals in prison longer would substantially reduce the overall crime rate. And so it has proven over the past generation of the swiftest record reduction of criminality in American history.

James Q. Wilson showed a way toward self-restoration that almost all the great American cities have followed.

Wilson thought about crime not only as a student of criminal behavior, but also — and maybe even more usefully — as a student of the behavior of government agencies.

For all the real-world importance of his work on crime, the most enduringly fascinating of his books may be his Bureaucracy.

He argued there against the tendency — urged by some economists — to see government agencies as equivalents to firms. Bureaucracies (Wilson showed) responded more to their internal culture than to external incentives. To improve the behavior of a bureaucracy, one had to change its internal culture — above all by defining finite tasks whose performance would improve results.

It was no good to set broad goals for agencies: those goals tended to contradict each other — or else to baffle the agency itself.

“Stop crime” is a goal. “Remove graffiti from the subway cars” is a task.

“End poverty” is a goal. “Require every welfare recipient to work a certain number of hours per week” is a task.

“Close the achievement gap” is a goal. “Drill students at XYZ high school until they can correctly answer the questions on ABC standardized test” is a task.

James Q. Wilson identified politically as a conservative. He was also a conservative in a deep intellectual sense: somebody who thought hard about institutions, who took an unsentimental view of human nature; who rejected attempts to reduce policy to abstract formulas.

Wilson epitomized and led that brilliant generation of dissidents who challenged the scientistic pretensions of the sociologists and criminologists of the postwar era — academics dazzled and infatuated by the dream of remaking all society. James Q. Wilson did not aspire to remake society. He regarded it as success enough to remake the Bureau of Narcotics and Dangerous Drugs.

Wilson developed a policy conservatism that was empirical; relevant; useful; and convincing even to those not predisposed to be convinced. It is a conservatism that often seems crowded to the margins by shouters and hucksters. Yet it is a conservatism that leaves an intellectual legacy that could be of the highest value again — if only that legacy were rediscovered, reappraised, and returned to service.

No man of thought ever served his society and country better than James Q. Wilson. We mourn his loss after his long struggle with illness. But as we mourn, we honor his work and cherish his mighty contribution.

Thank you, Professor Wilson.