A few words on the limits to freedom of expression:

For what it’s worth, there are a few that are acceptable. You don’t threaten or incite violence. You don’t defame. You don’t produce child pornography. And you don’t falsely shout “Fire!” in the proverbial crowded theater.

To these restrictions, Pope Francis wants to add another: You may not say anything that insults religious beliefs. “You cannot provoke,” he told reporters Thursday. “You cannot insult the faith of others.”

As you might have guessed, he was referring to the act of terror by extremist Muslims against Charlie Hebdo, a French satirical magazine known for provocative, scathing and even vulgar attacks on Islam — along with other religions, institutions and entities. The magazine was notorious for running cartoons of the Prophet Mohammed, even though many Muslims consider any representation of Mohammed to be deeply offensive. Twelve people died in the attack; one was a Muslim police officer.

So one can understand the pontiff’s concerns. But he could not be more wrong.

There is something in free people that instinctively rebels against being told what they cannot do, something that requires them to do the banned thing, not because they particularly need or want to do it, but, rather, as an act of self-assertion. So if you want to protect Islam from insult, the worst thing you can do is ban insults to Islam.

It is worth noting that, in America at least, most publications have long refrained from printing images of Mohammed. This came about, not from fear of violence, though that has become a concern in recent years, but, rather, out of deference to Muslim sensibilities. In the ordinary run of things, there is no particular reason to publish such images, and doing so would affront a great swath of humanity. Why give gratuitous offense?

Point being, left to our own devices, most of us police our own speech quite effectively. We don’t need threats or law to respect one another. We give respect as a matter of course.

Most of us. And then, there are the Charlie Hebdos of the world. In a free society, there always will be.

Shout back at them, if you must. Laugh them off or ignore them, if you want. But to censor them by force of law because you fear violence? Few things could be more antithetical to freedom — or more counterproductive.

After all, last week’s attack, hardly destroyed Charlie Hebdo. Rather, it elevated an obscure left-wing rag to arguably the most famous publication on Earth. The magazine’s first post-attack issue had an initial press run of 3 million against a normal run of 60,000. Even then, they couldn’t keep copies on the shelves.

Again, in a free society, the thing you seek to ban inevitably becomes the thing people seek.

While condemning the massacre, the pontiff also seems to feel the problem here is free speech. Using the hypothetical example of a friend who cursed his, the pontiff’s, mother, he argued that some things are so profoundly offensive you have to expect people to respond with violence. But the pope should ask himself: How many Catholics shot up how many newspapers over harsh coverage of the church’s sex scandals? The issue is not free speech but the fanaticism of some Muslims — some Muslims — who apparently believe they have a God-given right never to be offended — and to do violence when they are.

The worst thing the free world can do is seek to appease these unappeasable people by trampling our own fundamental values. If the pope doesn’t understand that, well … many of us do, as evidenced by the million people who descended on Paris Sunday to march in solidarity against terrorist repression.

One woman held aloft a sign that distilled the message quite nicely. “Freedom,” it said, “is nonnegotiable.”

Leonard Pitts Jr. is a columnist for the Miami Herald. Readers may write to him via email at: lpitts@miamiherald.com.