I had not known that the phrase “check your privilege” had become common on college campuses until an opinion piece by Tal Fortgang, a Princeton freshman, went viral. Fortgang observed that his left-liberal classmates deployed it in an attempt to silence his arguments about welfare or the national debt. His essay in response detailed his family’s struggles, showing that privilege did not capture the complexity of their lived experience.

Fortgang writes with passion, but his piece does not get to the root of what is wrong with the phrase nor does it show how it reflects more generally the pernicious norms that infect many of our universities. (I consider the norms of society as well as the law of the state a fit subject for this blog). Even if his family’s name had been Rockefeller or Frick, this kind of attack should not be welcome in intellectual discourse.

“Checking your privilege” does not impugn the logic or evidence behind any argument, but calls attention to the identity of the speaker. It is a variation on a classic fallacy–the ad hominem argument. Plato’s contentions in The Republic are not in need of reformulation because he was an aristocrat. Rousseau’s claims are not refuted because he treated his lovers and children badly.

Of course, in the political realm, we do often see attacks on the speaker rather than his platform. There that method may sometimes be justified, because political office holders not only make arguments but wield power. Character may make a difference to power’s exercise. But the often thinly veiled assaults on wealth or ethnicity, like some of those on Romney and Obama, were in essence appeals to prejudice and resentment. They may well be the price we have to pay for democracy. But a university is concerned with refining reason not exercising power, and the political focus on the person should not be allowed to distort the contest of ideas.

This ubiquity of “check your privilege” suggests that political correctness is now entering a second generation and gaining a second wind. While political correctness previously concentrated on race and gender, the new focus on inequality seems to have emboldened the campus left to put class back on the list of identity politics. Of course, using the phrase “check your privilege” to cut off debate on campus is not nearly as destructive as what communists did to people who were from the “wrong” class. Many children of privilege then were sent to reeducation camps to reflect or were even silenced never to speak again. But it stems from the same impulse to replace reason with power.

This new form of an old disorder also shows that despite the orthodoxy on many campuses many left-liberals remain very afraid of classical liberal and conservative dissent. Just as students who protested Condi Rice’s prospective graduation speech at Rutgers showed strength in numbers but weakness in intellectual confidence, so do those who parrot this new campus slogan. If your underlying argument is flawed, you do need a force other than logic and evidence to sustain your position. Political correctness is an admission of intellectual frailty.