"Cancel culture now poses a real threat to intellectual freedom in the United States," Jonathan Rauch, distinguished fellow at the Institute for Humane Studies, writes in Persuasion. Rauch cites a Cato Institute poll that found a third of Americans worry their careers will be harmed if they express their real political opinions. Canceling is different than healthy criticism, Rauch writes, because canceling "is about shaping the information battlefield, not seeking truth; and its intent—or at least its predictable outcome—is to coerce conformity[.]"

And conformity is a death knell for liberalism. In a homogenous society—one in which everyone has roughly the same background, religion, values, and goals—people will generally agree on what it means to be a good person and live a good life. But a key tenet of liberalism is pluralism: the idea that different people, traditions, and beliefs not only can coexist together in the same society but also should coexist together because society benefits from vibrant heterogeneity.

"Liberal thinking really arises out of a reflection on the fact that people disagree substantially about things," Chandran Kukathas, professor at Singapore Management University, says in a Big Think video on pluralism and toleration. "They have different ways of life."

[Cancel culture] is about shaping the information battlefield, not seeking truth; and its intent—or at least its predictable outcome—is to coerce conformity[.]

Throughout history, men and women who've changed the world have been living examples of pluralism—people whose lives and minds were unique products of a diverse, interconnected world. Alexander Hamilton was, as the musical Hamilton says, "a bastard, orphan, son of a whore and a Scotsman, dropped in the middle of a forgotten spot in the Caribbean" before he came to the colonies. Marie Curie (neé Skłodowska) was the daughter of two Polish teachers, one atheist and one Catholic, and attended an underground university in Warsaw before immigrating to Paris. Sergey Brin was born in the Soviet Union to Jewish parents before his family fled persecution and came to the United States, where Brin co-founded Google.

A pluralistic society nourishes innovation and progress, where diverse people with unique life experiences develop and share ideas. If people stayed in discrete, homogenous communities, how many world-changing lives and ideas would never have existed?

Critics might say: It's one thing to welcome people from diverse backgrounds into your society; it's another to welcome diverse ideas, even if some are offensive or harmful.

But our vibrant, evolving world depends on diverse ideas and cultures. In a homogenous society, ideas and customs can be stagnant for generations. But in a pluralistic society, ideas and customs evolve by being brought into constant contact with alternative ideas and customs. In On Liberty, John Stuart Mill writes:

…the peculiar evil of silencing the expression of an opinion is that it is robbing the human race; posterity as well as the existing generation; those who dissent from the opinion, still more than those who hold it. If the opinion is right, they are deprived of the opportunity of exchanging error for truth: if wrong, they lose, what is almost as great a benefit, the clearer perception and livelier impression of truth, produced by its collision with error.

For humanity to benefit from pluralism—to benefit from the exchange of cultures and the collision of ideas—we must practice toleration. We must respect the rights of our colleagues and neighbors to think and live differently than we do.

When someone practices toleration, Kukathas says, they don't just put up with something but actually acknowledge it "with a kind of open spirit." Intentional, meaningful tolerance includes making an effort to understand others' points of view. We don't have to agree, but we should seek to understand. And, ultimately, we have to tolerate ideas we disagree with if we want to live in a flourishing and peaceful society.

This is what cancel culture robs society of—the healthy and essential practice of toleration, without which pluralism and a peaceful society cannot be sustained.