Future graduates wait for commencement to begin at Yale University in New Haven, Conn., on May 24, 2010. (Jessica Hill/AP)

Anthony Kronman teaches at Yale Law School, where he served as dean from 1994 to 2004, and is author of “The Assault on American Excellence.”

Yale University’s Sterling Memorial Library was opened in 1931 , having been built to look 600 years older. Its walls are decorated with hundreds of stone carvings. Most are benign, a few deliberately humorous. Two years ago , the university announced plans to remove one carving from what it called a “place of honor” to a neutral setting where, in the words of Yale’s president, it could be viewed in a light that would help “all viewers understand” its “meaning” and serve as a stimulus to “thoughtful consideration and reflection.”

The carving depicts a Puritan and an Indian, peering around the column that separates them. The Indian holds a bow and shield; the Puritan, a musket. The musket appears to be aimed at the Indian, though whether in self-defense or hostility is impossible to say. Yet, after consulting with “faculty and other scholarly experts,” the university concluded that the carving “depicts a scene of warfare and colonial violence toward local Native American inhabitants.” The musket (but not the bow) was cloaked with a removable stone cover, pending the carving’s final move to an unspecified location. Today, a makeshift wooden blue box surrounds the carving — a coverup of the coverup.

The carving hardly occupies a place of prominence; to call it a “place of honor” is a stretch. It suggests that Yale meant to endorse the “colonial violence” the carving is said to portray — or meant to do so when the figures were carved nine decades ago. Neither seems plausible.

But the real problem goes deeper. The university’s treatment of the carving reflects the belief, shared by many schools, that our college campuses should be cleansed of names and artifacts that awkwardly remind their students that others in the past held values different from their own. Not erased entirely, as Yale’s president insists the university is not doing, but taken from their public places, where students have to view them as they go about their rounds, and retired to the anesthetized precincts of a museum where few, if any, will see them, and only those who choose to do so. It is hard to imagine a more compelling illustration of the phrase “safe space” that so many students and educators now enthusiastically embrace.

This kind of ethical cleansing is bad for many reasons. One is that it discounts the importance of discomfort in the process of learning. Discovering what your conscience demands is the reward for confronting ideas that shock it, and maturity is the prize of learning to live with ambiguity. Another is that it confirms the wish to have one’s field of vision seamlessly fit one’s system of values. It invites the smug belief that a real problem has been met simply by removing an irritant from view. A third is that it reinforces the belief that those who lived before us were blinded by prejudices we have thankfully overcome. But that itself is a prejudice — one that powerfully shapes campus life in an age otherwise devoted to the eradication of prejudice in all its forms.

This trend places moral self-confidence ahead of the life of the mind, which is always more than a little dangerous, because that adventure should put even our firmest convictions at risk. A university is not a family where love should rule. It is a community of conversation devoted to the search for truth. The moral beliefs that students bring to the conversation must not be allowed to curtail or confine it. Nor should their feelings be given the same weight there that they have around the kitchen table.

But the trend toward ethical cleansing puts our democracy at risk, too.

Our experiment in self-government is the most ambitious that human beings have ever undertaken. It is boisterous, contentious, divisive. To work at all, its citizens and leaders need to be able to see their opponents’ views not as the diabolical expression of wholly malign forces but as the beliefs of human beings whose ideas spring from commitments that even their enemies can partly acknowledge and perhaps even share. Our democracy needs what American jurist Learned Hand called the “spirit of liberty” and defined as “the spirit that is not too sure it is right.” It is needed on both the right and the left. Safe spaces on campus leave our students ill-equipped for the unsafe space of our wonderful but abrasive democracy.

Our students must of course be free from physical harm. But they must also be free from the spirit of moral conformity that today represents a danger of a more insidious kind. When their schools reinforce the belief that certain feelings need to be respected at all costs, and the injustices of the past stored away in a museum, they reinforce this spirit. They compromise the life of the mind. And they enfeeble their students for the hard work of citizenship that lies ahead.