How should Americans balance the values of equal respect and free speech? What role should universities play in protecting and promoting speakers? What makes free speech valuable anyway?

These questions have practical implications at UC Berkeley, where chancellor Carol T. Christ recently announced that the 2017-2018 academic year will be a free speech year. A “Free Speech Week”, planned by student groups and focusing exclusively on the ideas of right-wing speakers, has been called off after what looks like incompetent planning by the organizers.

It is worth taking a step back and considering the reasons for valuing free speech, and what sorts of policies those reasons support. (I will focus on moral and political reasons, rather than the legal status of speech on campus.) One set of reasons appeals to the good of the group; another appeals to the good of the individual.

In her defense of free speech, Chancellor Christ cites the philosopher John Stuart Mill. According to Mill, individuals are bad at discovering the truth: most of us hold strong opinions without the evidence or expertise to back them up. But the right group structure can help us do better: in a society with strong norms of free speech, we will encounter dissenting points of view that motivate us to rethink our opinions.

Even encountering false opinions can be helpful, since it ensures that our true beliefs will be held reflectively, and not as a matter of mere dogma. Christ echoes this sentiment when she writes that “truth is of such power that it will always ultimately prevail.” A closely related argument by Mill appeals to the untrustworthiness of authority: authority figures are no better at discovering the truth than the rest of us, and prone to censor views that they find inconvenient or unflattering.

This looks like a reason for permitting right-wing speakers on campus, but it also cautions us that there are limits to the amount of space a college should grant them. The planned right-wing speeches appear to have displaced a lecture by a distinguished anthropology scholar. If truth is our aim, making sure unpopular speakers are allowed on campus cannot be the whole of our strategy; we also need to strategize about how to stop loud, chaotic speech from drowning out quieter voices. A planned free speech conference by Berkeley’s Center for New Media will address some of these questions.

Let’s now consider reasons for free speech that appeal to the good of the individual. Citizens in a free society are entitled to a certain degree of freedom from interference. Other people cannot touch your body without your consent, or imprison you without due cause... and your right to liberty extends beyond the physical boundaries of your body. There are limits on the extent to which people and institutions can interfere with the things you own, or control the material you read. We can understand the right to free speech as an extension of this right to individual freedom.

This argument provides additional support for free speech on campus, but there are important limits on what it establishes. Individual freedom does not include the freedom to harm others. As the aphorism goes, your right to swing your fist ends where my nose begins.

We should draw a distinction, however, between harming others and offending them. Salman Rushdie so offended Ayatollah Khomeni with his novel The Satanic Verses that the Ayatollah placed a bounty on his head. Maya Angelou’s autobiography I Know Why the Caged Bird Sings has been banned for its discussions of racism (offensive to white people), and rape (offensive to a variety of sensibilities). These books may be genuinely confronting, but that’s not an adequate reason to ban them; the offense they cause is not the same as harm.

Milo Yiannopoulos, who was purportedly slated to speak at Berkeley, is useful for drawing the harm/offense distinction. Many of his ideas are deeply offensive: he has defended adults having sex with 13-year-olds, claimed that Black Lives Matter activists are more dangerous than white supremacists, and said “gays should pipe down and get back in the closet”. But this by itself is not enough to justify banning him from Berkeley’s campus.

Yiannopoulos’s speech is not merely offensive, however; it is also harmful. On multiple occasions, he has used his platform to directly threaten the rights of others, including students at the universities where he speaks. At UW Milwaukee, he harassed one student—who was present at his speech—by projecting a photograph of her onto the wall and mocking her for being transgender. He has threatened to publicly name undocumented students at Berkeley, putting them at risk of deportation, and he has begun targeting individual Berkeley students for internet harassment. (The internet attacks are part of a larger pattern; he was banned from Twitter after his followers bombarded Ghostbusters star Leslie Jones with sexist and racist tweets.)

There are good reasons, both moral and political, for upholding a right to free speech. But a moral right to express unpopular opinions is not a moral right to express those opinions in a way that silences the voices of others, or puts them in danger of violence. As Berkeley upholds the rights of individuals to express unpopular opinions, the university must also ensure that the loudest voices do not drown out everyone else, and that free speech does not become an excuse for harassment.