BOSTON —The president of Williams College has canceled a speaking event by a contentious writer who had been invited to campus by students.

In an email to students on Thursday, President Adam Falk said that the writer John Derbyshire, whose views have been criticized as racist, will not be welcome on the Williamstown campus. A student group called Uncomfortable Learning, which routinely hosts events with polarizing speakers, had invited Derbyshire to speak on Monday.

Only in extreme cases, Falk told students, would the college block a speaker from visiting. “There’s a line somewhere,” he wrote, “but in our history of hosting events and speeches of all kinds, we hadn’t yet found it.” But the president added that, with Derbyshire, who did not respond for comment, “we’ve found that line.”

“Many of his expressions clearly constitute hate speech, and we will not promote such speech on this campus or in our community,” Falk wrote.

On his website, Derbyshire calls himself a “novelist, pop-math author, reviewer and opinion journalist.” His writings have provoked backlash from critics who consider him a white supremacist.

He follows a series of polemical figures that Uncomfortable Learning has invited to campus. The group aims to challenge students by showing them differing opinions.

“I’m an African American and I disagree with John Derbyshire on almost everything he says,” said Zach Wood, a sophomore at the private college and president of Uncomfortable Learning. “But there are millions of Americans who happen to agree with what John Derbyshire says, and I want to wrestle with that argument.”

Colleges across the country have debated the limits of free speech on their campuses in recent years. In 2015, there were 20 attempts to disinvite speakers at U.S. colleges, either by students or college administrations, according to a database by the Foundation for Individual Rights in Education, a nonprofit that defends free speech on campuses.

In his letter, Falk wrote that he holds free speech in “extremely high regard” and that he expects students to explore challenging ideas.