Of all the reactions to the so-called Islamic State (IS) and its grisly, intentionally provocative brutalities, perhaps the most interesting one is surely unintended: it is inspiring critical and substantive debate about the nature of Islam, on the part of Muslims, a debate with the potential to bring about the modernization and reformation of that religion.

In decades past, it has been taboo even to hint at any possible anachronisms or problems in the Quran. And: “Islam is a religion of peace” was the universal obligatory mantra after 9/11. Only a daring few voices expressed the occasional doubt, to be instantly branded as Islamophobes.

And this politically correct version might have been true. Some of the theological observations made in this context had validity: it is true that almost all religions contain seeds of extremism and have engendered violent fringe movements. Certainly, the Quran also contains passages about justice, tolerance and communal peace. It is true as well that the Bible’s Old Testament contains multiple injunctions and sanctioned behaviors that shock us today—from infanticide to polygamy to rape. Judaism and Christianity have adapted their religions to changing mores by tacitly ignoring those passages that no longer fit the times, and by accepting that some aspects of religious doctrine are historic, rather than ethical or theological.

But the sentence about Islam being a religion of peace was never a theological statement. It always had an ulterior motive: the desire to be polite, to be politically correct, and to wish into being a desired reality. I have attended more than one academic conference where an incipient discussion of Islam was anxiously aborted with the warning that “one can’t go to war with 1.6 billion people.” This statement in itself, of course, pretty much negates the religion of peace premise, presuming as it does that an angry horde would be ready to rise up if it didn’t like your panel’s comments. “Religion of peace” was an invocation more so than a diagnosis.

IS allows for no such blandishments. IS wants no part of any religion of peace, which leaves us with two possibilities: either IS is not Islamic, or Islam is not peaceful. Our preferred answer is the first one, but IS is determined to beat that one out of us. IS gives Christians 24 hours to decide whether they want to pay a punitive tax, convert or be killed. It slaughters prisoners. It takes female captives as sex slaves and concubines. It expresses vitriolic hatred of Christians and Jews. And that’s its friendly face. Belong to any other religion besides those, and genocide is your destined fate. Its goal is to spread its dominion by the sword and to establish a Caliphate. And it claims that all of this is in fulfillment of Islamic doctrine and the word of the Quran. And, it regretfully must be said, that happens to be true.

The world can debate and dispute this claim if it wishes, but the matter is easily settled: just read the Quran. And what you will discover is that the things IS is doing are indeed contained chapter and verse in that document. The Quran explicitly permits the taking of prisoners of war as slaves. It specifically allows you to ignore the married status of any female prisoners that you fancy, and to force them to become your concubines or wives. It is filled with hateful descriptions of Christians and Jews, although it does grant them special status as followers of earlier prophets and “people of the Book” and provides for them to be tolerated as second-class citizens in exchange for paying, essentially, protection money or a blood tax. No such kindness extends to followers of other religions or creeds, who are idolaters to be eliminated, a policy that IS has diligently followed towards the Yazidis. Sure, there are other passages and sentiments expressed in the Quran as well; we have chosen to focus on those and sweep the rest under the carpet. IS has yanked that carpet out from under our feet.

Responses to IS include abhorrence, NATO alliances and air strikes. The deeper result may, however, be far more consequential: a reassessment on the part of Muslims of their religion, of that 1.6 billion minus the few thousand IS hardcore literalists. And indeed this is happening already, on platforms ranging from academic forums to social media. Things are being articulated, questions boldly raised, daring hypotheses uttered, breaking a generations-long silence. Take, as just one example, the article by Turkish scholar Necla Kelek: Muslims, she says, have neglected to develop habits of critical analysis and discourse, and instead have favored “taqlid,” the practice of blindly accepting whatever came before. This has given free reign to the regressive thinking of the Salafists. “Peace-loving Muslims will forever be helpless against the fundamentalists unless they begin to define the Quran, too, as a historical text subject to inquiry, critique and doubt. They must prove themselves ready to take their place in a secular world.”

Even more startling, you will find—for the first time in modern history—blogs and postings by ordinary Muslims, on websites in Islamic countries, not merely critiquing Islam, but even renouncing it in angry, sometimes obscene language. Some of these postings, from outside the Arab heartland, equate Islam with the Arabs and pour contempt upon them also, blaming them for the fanaticism and backwardness and violence that has plagued the religion. That’s the pendulum swinging to the opposite extreme, but it makes one thing clear: IS has succeeded in blasting away the polite veneer, unfreezing the dialogue. It says to the world’s Muslims: Is this what you are? A swaggering bunch of blood-drenched murderers and rapists? Is this the true spirit of that book that you wrap in brocade cloths and claim to aspire to follow down to each and every word and syllable, unquestioningly and literally? Or is it maybe time to unwrap it and take another look, and perhaps even—modern Christianity’s method—leave certain passages behind as the centuries pass and humanity, hopefully, advances?

In this new debate, the West should focus on practical and kinetic contributions: providing military and logistical support and moral encouragement to those who are combating IS, especially the Kurds. We should, however, stay well out of the theological discussion. When the dust finally settles, we may find that IS has given the world a lasting, if expensive, gift: the long-overdue Islamic Reformation.

Cheryl Benard is the president of Metis Analytics, a Washington based research firm. Her book Eurojihad, Cambridge University Press, will be published next month.