The Long Divergence

In the year 1000, the largest city in Europe was not Paris or London. It was Córdoba, capital of a Muslim caliphate, home to some 100,000 people and, in Britannica’s judgment, probably the most cultured city on the continent. Three thousand miles east, Baghdad had just completed a two-century project in which the whole Abbasid elite, from caliphs down to merchant families, paid to move nearly the entire scientific inheritance of Greece, Persia, and India into Arabic. One family of patrons, the Banu Musa brothers, paid translators roughly 500 dinars a month. Translation was a lucrative profession in Baghdad while most of Europe was struggling to keep literacy alive in monasteries.

The economist Timur Kuran opens his book on this subject with the ledger: in the year 1000, the economy of the Middle East was at least as advanced as Europe’s; by 1800 the region had fallen dramatically behind in living standards, technology, and economic institutions. He calls it the long divergence, and the name has stuck. The civilization that taught Europe its numerals ended up colonized, in large part, by the students.

Something happened. And when Christians reach for an explanation, we tend to grab one of two stories. In the first, a Muslim theologian named al-Ghazali wrote a book that murdered science. In the second, the Ottoman sultans banned the printing press on pain of death and sealed their empire off from the modern world. Both stories are simple. Both are false, and the scholars who checked them can show you exactly where they break.

I want to clear away the myths first, because this series has one standing commitment: the case against Islam’s political-theological package gets made from evidence that survives hostile checking, or it doesn’t get made at all.

The philosopher who didn’t kill science#

The story runs like this. In 1095, al-Ghazali published The Incoherence of the Philosophers, a theological attack on the Greek-influenced rationalists. He won. The “gates of ijtihad” (independent reasoning) slammed shut, and science in the Muslim world froze to death.

Almost every load-bearing piece of that fails on inspection.

Start with the gates. Wael Hallaq’s 1984 study “Was the Gate of Ijtihad Closed?” went through the juristic literature and found Muslim jurists practicing independent reasoning for centuries after the gates supposedly shut. The “closure” is a later construct, not a medieval event.

Then the science itself. George Saliba’s Islamic Science and the Making of the European Renaissance documents that the most mathematically sophisticated astronomy the Islamic world ever produced came after al-Ghazali died in 1111. The Maragha observatory was founded in 1259, one year after the Mongols sacked Baghdad, by a scholar working under Mongol patronage. Ulugh Beg’s observatory at Samarkand ran until 1449. Taqi al-Din built an observatory in Istanbul in 1577, generations into the supposed dark age. And the case that should end the argument: Ibn al-Shatir, the official timekeeper of the Umayyad Mosque in Damascus, a man whose day job was calculating prayer times, produced fourteenth-century planetary models that are mathematically identical to the models Copernicus later used for the Moon and Mercury. Whether Copernicus got them from the Damascus tradition is contested (the equivalence is established; the transmission route is probable but undocumented, per Saliba). Either way, the man supposedly living in the ruins al-Ghazali left was out-deriving Europe four hundred years after the murder allegedly took place.

Al-Ghazali himself, for the record, endorsed mathematics and logic as religiously neutral and warned believers that attacking them discredited the faith.

There is a defensible residue, and honesty requires stating it. The economist Eric Chaney tracked centuries of book production and found a sustained decline in innovative scientific output beginning in the twelfth century, alongside a rising share of religious titles and religiously employed authors. He reads it as religious elites gaining political power and shifting the incentives facing bright young men. Historians of science like Sonja Brentjes push back on single-cause internalist stories and document the sciences still being taught around the madrasas. So a slow shift of prestige toward the religious sciences is a live, contested thesis. A murder is not. The astronomy kept running for four more centuries.

The printing ban nobody can produce#

The second story is more specific, which makes it easier to check. As usually told, Sultan Bayezid II banned printing in 1485, Selim I renewed the ban in 1515, and the penalty was death.

Kathryn Schwartz went looking for the decrees. Her 2017 study in Book History, “Did Ottoman Sultans Ban Print?”, found no surviving Ottoman documentation that these edicts ever existed. The story originates in early modern European accounts explaining why the Ottomans didn’t print, was later absorbed by nineteenth-century Ottomans themselves, and then hardened into twentieth-century scholarship. A European guess about the Ottomans became the Ottomans’ own memory, and then everyone’s history.

What the record actually shows is stranger than the myth. Presses operated openly in Istanbul for centuries. Sephardic Jews expelled from Spain were running a Hebrew press there from 1493, one year after the expulsion. An Armenian press followed in 1567, a Greek one in 1627. Nobody was executing these printers. What did not exist until 1727 was Muslim-operated printing in Arabic script, and when Ibrahim Müteferrika opened that first press, he did it with a fatwa and an imperial license, which is the opposite of defying a capital ban. His press printed about 17 titles before closing.

Why did Muslim printing wait 234 years after the Jewish press down the street? The documented answers are economic and cultural: tens of thousands of copyists whose livelihoods printing threatened, the religious prestige of calligraphy, the genuine technical difficulty of Arabic typography, and, on Schwartz’s reading, the absence of felt demand. The consequences of that 250-year gap for literacy and the diffusion of knowledge are a real and still-debated question. But “they banned the book on pain of death” belongs on the shelf with al-Ghazali’s murder weapon.

The case Kuran actually makes#

Clearing the myths doesn’t answer the question; it sharpens it. Baghdad and Córdoba really did lead the world, and Cairo and Istanbul really did fall behind it. The most serious explanation on the table comes from Kuran’s The Long Divergence, and his target is precise: not Islam as belief, but Islamic law as an economic operating system.

Three mechanisms interlock. Islamic partnership law dissolved a partnership at the death of any partner, so no enterprise could safely outlive its founders. Islamic inheritance law mandatorily fragmented every estate among many heirs, a fragmentation amplified by polygyny, so capital scattered every generation instead of accumulating. And Islamic law never developed the corporation: no legal person that owned property in its own name and outlived its members. The one instrument that locked capital together across generations, the waqf (pious trust), froze it instead, binding enormous wealth to the founder’s stipulated purposes in perpetuity. Waqfs built schools and hospitals, and they also made the capital inside them permanently unavailable for anything else.

I’m an engineer by trade, and Kuran’s argument reads like a failure analysis. It isn’t a story about intelligence or piety. It’s a story about compounding: a system where every firm resets to zero at a founder’s death, and every fortune shatters at probate, has no accumulation path. Europe’s corporations, from chartered towns to joint-stock companies, were machines for surviving their members. Systems that can’t form corporations can’t compound, and given eight centuries, the gap between compounding and not compounding becomes the gap between the colonizer and the colonized.

Kuran’s most telling exhibit is what happened when the rules got a bypass. Under the capitulation treaties, non-Muslim minorities could opt into European legal jurisdiction, and by the nineteenth century Christians and Jews dominated Middle Eastern commerce. Same cities, same markets, same climate. Different law, different outcome.

Now the required caveat, because this is a live debate and not a settled verdict. Reviewers with expertise in Islamic law and economic history have pushed back: certain partnership forms did survive a partner’s death, waqfs were used more creatively than the argument allows, European entails were comparably rigid, and the divergence may date later and owe more to politics than the thesis needs. The fair summary from the economic-history reviews is that Kuran’s is the most serious institutional account on the table, taken seriously and contested, not consensus.

Two more serious contenders#

Toby Huff asks why Europe grew legally autonomous corporate bodies, universities and guilds and chartered cities, each a protected space where inquiry had legal standing, while the madrasa, founded as a waqf, stayed bound to its founder’s religious purposes with the rational sciences outside the core curriculum. His critics answer that the sciences were in fact taught around the madrasas and that Europe’s universities were pious foundations too.

Joel Mokyr’s A Culture of Growth barely mentions Islam, and that is its contribution. His explanation is about Europe: political fragmentation plus a border-crossing Republic of Letters meant heterodox thinkers could survive by exit, the way Descartes left France and Hobbes and Locke left England, while their ideas kept circulating. A large unified empire, Ottoman or Qing, could enforce orthodoxy across the whole space. On this account the question “why did Islam stall?” is half mis-posed; the anomaly needing explanation is Europe.

Historians of science like Saliba and Brentjes largely agree with that reframing: Islamic science didn’t uniquely collapse so much as Europe accelerated, and into the sixteenth century Islamic observational astronomy remained world class. Where the field does agree is negative. The old internalist story, al-Ghazali plus the Mongols plus fatalism, is inadequate, and no single-cause replacement has won.

Why the institutional answer is the hopeful one#

Notice what every serious explanation has in common. Kuran indicts contract and inheritance law. Huff indicts the missing corporation. Mokyr credits Europe’s fragmentation. Chaney tracks elite incentives. None of them says the people were the problem.

That matters to me as a Christian in two directions. First, it kills the sneer. Anyone tempted to explain the divergence by genes or by some curse on a billion people has to get past the actual record, which includes Ibn al-Haytham founding experimental optics and a Damascus mosque timekeeper matching mathematics that Europe wouldn’t see for another century. Scripture already told us where that record comes from: “God created man in his own image” (Genesis 1:27), and the image-bearers of Baghdad and Damascus proved it. If institutions caused the stall, then the stall is not fate. Laws are decisions. Decisions can be remade.

Second, it disciplines the critique. This series exists because I believe Christians must understand Islam’s political-theological package clearly, and this article is part of that case: a legal system reaching into contracts and inheritance and endowments had civilizational consequences its adherents never voted on. That is a hard critique, and the sources carry it. What the sources will not carry is contempt, and contempt is also terrible witness. I want my Muslim neighbors to meet Jesus. A Christian who repeats the printing-ban legend to a Muslim engineer who knows better has lost the conversation before it starts, and deserved to.

So here is the concrete takeaway. The next time a preacher or a podcast tells you al-Ghazali murdered science or that the sultans banned the press on pain of death, you know the two papers that checked: Hallaq, 1984 and Schwartz, 2017. Send them. The case we have against the system is strong enough that we can afford to lose the myths. The final article in this series is about what that case means for the neighbor across the street.

Go deeper#

• Timur Kuran, The Long Divergence: the full institutional argument, readable by non-economists, with all the legal mechanics laid out.
• Dimitri Gutas, Greek Thought, Arabic Culture: how the golden age was actually assembled, against both the triumphalist and dismissive tellings.
• George Saliba, Islamic Science and the Making of the European Renaissance: the post-Ghazali astronomy the decline story ignores, through the Copernicus connection.
• Joel Mokyr, A Culture of Growth: the Europe-side answer, and the best argument that the question itself was pointed the wrong way.