A vigil at the Brandenburg Gate to commemorate the victims of the recent terror attacks in Paris.  (Sean Gallup/Getty Images)

The murders of cartoonists and French police officers at the newspaper Charlie Hebdo last week have sparked a vigorous debate about tolerance for, and even encouragement of, blasphemy in a free society. As I wrote at the time, I think all more moderate people should recognize that they owe a debt to blasphemers and satirists, who create a free speech zone in which the rest of us can operate. But in discussing the potential costs of the Charlie Hebdo attacks and other violent responses to crude depictions of the prophet Muhammad, it’s important that we acknowledge the full spectrum of speech that’s in potential danger.

Reza Aslan, a University of Southern California professor who has written books about Jesus as a historical figure and the history of Islam, told me it is important for non-Muslims and Muslims alike to understand that the taboo against depicting Muhammad and other prophets is not drawn from the Koran or even a settled matter of Islamic law. Rather, it is a product of specific cultural circumstances and the way Islam sought to set itself apart from Christianity.

“The first [factor in the development of iconoclasm] was a deliberate attempt among the early Muslim community to not allow the prophet Muhammad to transform into an object of worship. This was the early Muslim community’s, and even the Koran’s, greatest criticism of Christians. They were worshiping Jesus as if Jesus were God, when in fact Jesus was just the prophet and the messiah,” Aslan said.

The second factor in the evolution of the taboo was Islam’s focus on literacy. “The scriptures are endowed with divine power, the actual words, the actual letters on the page are endowed with divine power,” he explained. “Which is why conservative Jews and conservative Muslims treat their scriptures with special care. They’ll use gloves in handling it or a stick in handling it, they won’t allow scriptures to be destroyed or defiled.” Rather than employing the images that made up for many Christian believers’ inabilities to read the Gospels for themselves, Islam encouraged believers to learn the Arabic skills that would let them read the Koran.

“The history of Islam teems with images of the prophet Muhammad. There are tens of thousands of images of the prophet Muhammad, throughout history, drawn by Muslims. They are images from his entire life,” Aslan noted.

And while in recent years, images that were designed to give deliberate offense have met with violent responses, members of certain extremely conservative Muslim sects have destroyed respectful images of Muhammad and sites associated with the prophet and his family.

“The first thing the Wahhabis did when they burst onto the scene was to go around destroying all these sacred tombs of the prophet and his family throughout the Arabia. Because even though [those sites] were of the prophet himself, their iconoclasm forbade these things to exist,” Aslan explained. “They were just barely stopped from destroying the prophet’s tomb and the central area in Medina, the first mosque.”

This is hardly a dead issue: Last year saw the revival of a proposal to demolish Muhammad’s memorial site and bury his remains in an unmarked grave.

Aslan suggested that accepting the idea that depicting Muhammad and the other prophets violates Muslim law, rather than looking at the issue as one that has been contested throughout the faith’s history, was to fall into a kind of trap.

“We readily accept the narrative of the extremists and the loudest voices, because it’s the only voices that we hear. For the vast majority of non-Muslism, their belief in what a Muslim thinks, believes, and strives for is predicated on the Muslims they see on Fox News. So of course they believe that when a Muslim says the Koran says that if you depict the prophet, you should have your head cut off — which is ridiculous — or that the punishment for blasphemy is death,” Aslan said, “[That person] is simply mimicking the views of the extremists.”

What would it look like if circumstances were different?

“In the United States today, Christians are expected to accept that the lives of Jesus and Mary and others are the property of artists and entertainers, not just the faithful, and that they can be rewritten (and, needless to say, frequently sexualized) for the sake of bestselling potboilers, transgressive plays, pseudo-histories, literary ‘experiments’ and Very Important Cultural Events alike,” Ross Douthat wrote in the New York Times Wednesday, considering the arguments and blasphemy and offensive-giving that have followed the attack on Charlie Hebdo. “Christians are expected to accept that both our holiest figures and earthly leaders will be represented in avant-garde art, not only unflatteringly or satirically, but using prophylactics, urine or excrement.”

This catalog of what Christians are asked to tolerate in the name of free speech is also a list of the culture that can be produced because artists and entertainers can trust that their work won’t be met with a violent response. Much of the response to the killings at Charlie Hebdo has focused on the right or even necessity to disseminate extreme speech, and not unjustifiably; Dieudonne M’bala M’bala, a comedian of French and Cameroonian descent, was arrested Wednesday for a Facebook post that appeared to be supportive of one of the Charlie Hebdo gunmen in a vivid illustration of France’s own restrictions on speech. He is hardly the only person to have been detained on these same grounds.

But it’s also worth considering which less-extreme voices are being silenced either out of belief that it is always improper to depict Muhammad or out of fear of retaliation from people who believe that such images violate religious law.

The violent responses to “The Innocence of Muslims,” the provocative — and low-quality — film that played a role in sparking protests that gave cover to the attack in Benghazi, Libya, might not seem to be an indicator of risk for a more respectful project about Muhammad, like two that are in production in Qatar and Iran.

But as the Hollywood Reporter explained in 2013, one of the projects had already been met with calls that it be banned on the grounds that it showed part of the prophet’s body, though it does not reveal his face.

And other aspiring filmmakers might have to consider the example of “The Message,” a 1977 movie that, as Aslan points out, made the creative choice to use the camera as Muhammad’s eyes, letting viewers share his perspective in a way that precluded director Moustapha Akkad from showing the prophet’s face. That tactic didn’t prevent a group of Muslims who followed the Hanafi theory of legal jurisprudence and were lead by a man named Hamaas Abdul Khaalis from treating “The Message” as a provocation and using the movie to call attention to other grievances. They took nearly 150 hostages in Washington, killed a radio reporter and shot then-D.C. Council member Marion Barry.

More recently, Darren Aronofsky’s “Noah” was banned in a number of majority-Muslim countries for depicting a prophet. That movie had built-in Christian and action movie audiences in the United States in the way a look at the life of Muhammad might not. The difficulty of getting a Muhammad movie into theaters in significantly Muslim countries, as well as the possibility of protests and even violence in countries where such a film did make it to theaters, seems likely to deter an industry that is more and more attentive to the preferences of overseas moviegoers.

It’s also important to remember that the Danish cartoon controversy was in part a response to what editor Flemming Rose described in The Post in 2006 as a cultural retreat.

“Last September, a Danish children’s writer had trouble finding an illustrator for a book about the life of Muhammad. Three people turned down the job for fear of consequences. The person who finally accepted insisted on anonymity, which in my book is a form of self-censorship. European translators of a critical book about Islam also did not want their names to appear on the book cover beside the name of the author, a Somalia-born Dutch politician who has herself been in hiding,” Rose wrote. “Around the same time, the Tate gallery in London withdrew an installation by the avant-garde artist John Latham depicting the Koran, Bible and Talmud torn to pieces. The museum explained that it did not want to stir things up after the London bombings. (A few months earlier, to avoid offending Muslims, a museum in Goteborg, Sweden, had removed a painting with a sexual motif and a quotation from the Koran.)”

The affair finally came full circle when Yale University Press published an academic book about the response to the cartoons that declined to reproduce those images or other depictions of Muhammad, discussing them in absentia. Responses like these raise questions about whether museums might hesitate to display more respectful images, like the folios from the “Compendium of Chronicles” of Rashid al-Din, which include a number of depictions of Muhammad at various points in his life.

Aslan suggests that while such decisions often come out of a desire to be respectful, they don’t just deny audiences important opportunities to see powerful relevant images, but they reinforce a kind of soft anti-Muslim sentiment.

“The idea that Yale University Press thought that a book that 13 people would read anyway, an academic tome about the cultural, political and religious ramifications of these images,” he said, “that somehow that would threaten the lives of Yale University Press employees, it’s that kind of silly, knee-jerk cowardice that only feeds into this notion that Muslims are this kind of irrational, almost animal-like being who have to be handled with gloves.”