Abie Nathan was an Iranian-born Jew of Yemeni extraction who was educated in British India, flew for the Royal Air Force, bombed Galilee villages and the Egyptian Army on behalf of his adopted Israel during the 1948 Arab—Israeli War, and went on to introduce Israelis to the pleasures of the hamburger through his Tel Aviv restaurant, the California. In 1966, having made it his mission to end the hostility between Israel and its Arab neighbors, he flew a biplane over enemy Egyptian territory and landed at Port Said; there, he requested an audience with President Gamal Abdel Nasser and was politely deported. In 1973, Nathan founded an offshore radio station, the Voice of Peace, that broadcast from a ship “somewhere in the Mediterranean” in English, French, Hebrew, and Arabic to nearly 30 million listeners. Although twice jailed for having unauthorized contact with the enemy (including a meeting with Yasir Arafat), Nathan was unrepentant, arguing that “it will be impossible to heal the wounds, whether among the Arabs or the Jews, unless we decide to sit with each other.” In 1993, after the Oslo Accords were signed, he shut down the Voice of Peace, believing that his work was finally done.

If Nathan’s effect on the Arab-Israeli conflict was immaterial, fleeting, and impossible to measure, and if his compatriots looked on him as something between a joker and a knave, his example has nonetheless been significant to the Palestinian philosopher and sometime PLO official Sari Nusseibeh, who wrote about him in his 2011 book What Is a Palestinian State Worth? Nusseibeh has also written about another admirable figure who persisted in seeing the humanity of his adversary: Izzeldin Abuelaish, a Harvard-educated Palestinian doctor who lost three daughters to Israeli shells during the obliteration of Gaza in 2008–9, but who, like Nathan, continued to insist that Israelis and Palestinians needed to teach each other love and respect. Here was “a modern-day Job,” in the words of one journalist, who “continues to speak the language of peace.”

The better natures of Nathan and Abuelaish seem to flow into a course that has been cut by human reason; they exhibit what Nusseibeh calls a unified, or “conjunctive,” account of the way we behave. In opposition to the classical dialectic that pits the physis, the brutal and atavistic side of behavior, against the nomos, or reason-based laws, in Nusseibeh’s telling human conduct is informed by a single compound of gut and nous.

It’s easy to see how people whose political positions were formed by a yearning to reconcile the superficially irreconcilable would attract the attention of this eminently civilized member of the old Jerusalem aristocracy (a Nusseibeh has held the keys to the Church of the Holy Sepulchre on and off since the Arab conquest of Jerusalem in 637). It’s also easy to see how they might be attractive to a philosopher and educator who has spent a long and ambivalently pursued public career with his finger jammed painfully in a dyke behind which the hate has accumulated. A man who has given his life to education and philosophical contemplation, on the one hand, and to the Palestinian cause whose essential justice has often been tainted by peculation and Islamist militancy, on the other, and who moves between churning East Jerusalem and the millponds of Harvard, Nusseibeh is someone who knows all about contrasts and contradictions.

In 2001, during a brief stint as Arafat’s representative in Jerusalem, Nusseibeh tried to smother the biggest contradiction of them all when he announced to a packed hall at the Hebrew University that Israelis and Palestinians were not enemies at all, but rather strategic allies: “Our mutual interest that the future be better than the present,” he wrote later, “creates an objective alliance between us.”

Arafat valued Nusseibeh for his moderation, international reputation, and contacts among Israeli peace activists. But he also kept him at arm’s length for the same reasons. In the early 2000s, during the second intifada, Nusseibeh devised a peace plan with a former Shin Bet chief, Ami Ayalon, that garnered support from many ordinary people on both sides. But a darker vision uniting the Israeli right and Palestinian militants around their opposition to coexistence defeated these hopeful moves—a defeat made manifest by Ariel Sharon’s security fence through the West Bank, though a protest movement organized by Nusseibeh prevented it from bisecting the campus of Al-Quds University, whose president he’d become in 1995.

The growing militancy of young Palestinians and the increasing political dominance enjoyed by the Israeli right were never going to favor the philosopher. His presidency of Al-Quds ended in 2014, when he was forced to step down after an on-campus show of strength by Hamas and Islamic Jihad upset the university’s American partner, Brandeis. Nusseibeh chose not to condemn the militants’ actions; Brandeis took umbrage; and his retirement was announced shortly afterward. These days, still shuttling between the West and Palestine at age 68, Nusseibeh seems to have embraced once more the life of contemplation, philosophy, and Islamic thought from which, one suspects, a vivid sense of noblesse oblige wrested him in the first place.

Along with studying the most enduring political dispute in the modern Middle East—this fall marks the 100th anniversary of the Balfour Declaration—Nusseibeh has spent much time mulling over what many critics of Islam consider to be the religion’s besetting flaw: its antipathy to reason, which has, so the argument goes, prevented it from accommodating the ideas of individualism, empirical knowledge, and liberation from dogma that constitute modernity.

In an Islamic context, the word “reason” is often employed as a sarcastic counterpoint to the religion itself, and the trope of Islamic unreason—or rage, or a furious inferiority complex—has helped sustain the “clash of civilizations” theories that have been given such a boost by the growth of terrorism in the Middle East and Europe and the answering clarion of Donald Trump, Geert Wilders, Marine Le Pen, and others. But if reason and Islam were shown to be long-standing friends, even to inhere naturally in each other, this might be more significant than a strategic alliance between, say, the Palestinians and Israelis. This, at least, is what Nusseibeh promises in his new book, The Story of Reason in Islam.

A common view of Islamic reason in the West holds that while questions over free will and the Quran’s eternal nature encouraged a certain amount of speculation among early Muslims, it was only after the assimilation of Western thought—first Greek thought in Alexandria, which flourished as a center of Neoplatonism even after it fell to Arab conquest, and later through the translation of Greek works into Arabic—that Islamic thought began to develop its own rationalist tradition. This, in turn, led to the achievements in mathematics, astronomy, and chemistry that gave shape to the golden age of Muslim intellectual achievement under the Abbasid Empire, a cultural superpower dominant from Iberia to China.

But not all Western scholars subscribed to this backhanded account of Islamic rationalism, which depicts reason as extrinsic to the Islamic tradition; some, like the 19th-century French Orientalist Ernest Renan, dismissed “Islamic science and philosophy” as “but a petty translation of Greek science and philosophy.” Falsafa, the Arabic word for the discipline that entered the Abbasid world with translations of Galen, Plato, and Ptolemy, was painfully foreign in origin, and it wouldn’t be until Avicenna in the 11th century that the Arabic language fully indigenized Greek and Hellenistic philosophical concepts. Sari Nusseibeh’s story of Islamic rationalism makes the case that reason didn’t in fact enter Islam through falsafa, but through kalam, a discipline—-probably influenced by Christian theology—that subjected the Quran to discussion and analysis in everyday Arabic.

While relying on many of the same philosophical and critical techniques as Christian theology, kalam was also much more worldly than falsafa. As Nusseibeh writes concerning the endeavors of one Hasan al-Basri (642–728), who is generally identified as the first exponent of kalam: “This was no ‘ivory-tower’ debate about academic subjects such as justice, free will and responsibility based on books picked up from the library. It directly affected peoples’ lives…. Because [Basri] understood the Qur’an as the intellectual space in which rational enquiry can proceed freely.”

The Quran is a famously allusive, repetitive, contradictory text, convincing many—among them Thomas Carlyle, who famously described it as a “wearisome confused jumble”—-that it could never serve as the forum for an exercise of rational inquiry. In the most surprising and dramatic assertion of his book, however, Nusseibeh counters that “had it not been for the Prophet”—and, by implication, the Quran—“reason, rooted in efforts to understand and explain this faith, would not have flourished” in the Middle East. In fact, for Nusseibeh, it is precisely the Quran’s difficult and poetic style that makes it “a progenitor of reason,” because only reason can aid us in understanding it. This explains the astonishing, liberating force of the Quran, a poetic work that “possessed a universal scope and rang forth on a scale without precedent.” The words of the Prophet “elevated the spirit to unparalleled heights: reason in Islam was born.”

Thus, in a lyrical and romantic vein, Nusseibeh opens his story of how the Islamic world began to use rational methods to deal with the Quran and its conundrums. Over some 230 closely argued pages, he describes the fluctuating fortunes of reason, from the ninth-century Mutazilites, who championed free will, to the philosopher Alfarabi, Baghdad’s Montesquieu (he elaborated an early theory of nationhood), and on to Avicenna, who in his masterpiece, Al-Shifa (“The Healing”), reconciled Islamic revelation and classical knowledge.

Nusseibeh also includes a dazzling list of intellectual freelancers in his compact book, from the astronomer al-Haytham in Fatimid Cairo to the polymath al-Biruni 4,000 miles away in Bukhara (where he met Avicenna) and al-Maarri, a freethinking Syrian who held that all religions and prophets were false—and got away with it (until 2013, that is, when his statue was beheaded by jihadists).

As the medieval period wore on, however, the widening schism between Sunnis and Shiites, combined with external shocks like the Crusades, dented the faith of Muslims in their cultural supremacy, and some began to believe that rationalism was the reason for God’s displeasure. One of these was Ibn Taymiyyah (1263–1328), the Muslim theologian and a refugee from the Mongols. Under his influence, philosophy was downgraded in the religious schools and the principle of taqlid, or emulation of those with religious authority, was privileged over ijtihad, the exercise of independent reasoning—which was only acceptable within the bounds of a Sunni orthodoxy that had been exhaustively and rigidly codified, even if among the minority Shias dynamic ijtihad has remained a tool of jurisprudence to the present day.

When it comes to explaining the calamitous decline in reason’s cur-rency by the 17th and 18th centuries, Nusseibeh doesn’t dwell on political events or the triumph of taqlid, but on a diminished means of communication in the Muslim world that he dates to the rise of the Ottoman Middle East. The shared milieu of Muslim savants who had exercised their rational faculties in the medieval heyday, he writes, was a vast and varied cultural space “held together by the Arabic language of the Qur’an.” But when Ottoman Turkish became the language of power from Hungary to Basra and North Africa in the 16th century, Islam lost its common “factory” for intellectual innovation. The distances between different Islamic thinkers grew, as did those between the Quranic Arabic of the Prophet’s time and the various spoken dialects from Morocco to the Persian Gulf. As Nusseibeh concludes gloomily: “Once the lingua franca of reason and science, Arabic ceased to play this role, shrinking back to becoming the ‘property’ of the Arabs.”

Taken altogether, Nusseibeh’s account of the decline of reason in Islam is less convincing than his account of its rise. Laying the blame on the Turks obscures the fact that great Islamic schools like al-Azhar in Cairo, dominated by Arabic speakers, also subsided into scholasticism around this time and ceased to produce original ideas. Nusseibeh contrasts the early Arab empires’ eager exploitation of paper technology after it was introduced from China in the eighth century with the Ottomans’ opposition to movable type. But the hostility to new technologies and ideas was by no means confined to the Ottoman Turks in the 17th and 18th centuries, and neither is it certain that Arabic was the only possible means of expressing rational values in an Islamic context. To take just one example: In the second half of the 16th century, Islamic reason reached a peak in the Mughal court of the Emperor Akbar, whose famous ecumenical debates were conducted in Persian.

Though the shrinking compass of the Arabic language may have played a subsidiary role in the slow decline of Muslim reason, it seems to have been caused by many other historical reversals as well: The homogenization of “official” Sunni Islam under the weight of a massive imperial bureaucracy organized by the Ottomans combined with external shocks such as the Crusades, the reconquista of Muslim Spain, and the Mongol invasions to dent Muslims’ faith in their own supremacy. This, in turn, engendered a defensive impulse to contract the intellectual world of Islam in the face of the economic, cultural, and military prowess of the West.

The revival of reason in the Islamic world in the 19th and early 20th centuries, and its rejection, once again, by many Muslims in our own time, offers an important coda to Nusseibeh’s story. One of the first modern Middle Easterners to express himself on the subject of reason was the prominent Egyptian cleric Abdulrahman al-Jabarti, whose position meant that he had much contact with the French after Napoleon’s invasion. For all the military superiority that had allowed the French to sweep imperiously into Cairo, the occupiers’ debauchery and ill-advised egalitarianism appalled Jabarti. “France,” he sniffed, was a country “without religion but which obeys the judgment of reason.” But as Europe’s penetration of the Middle East intensified during the 19th century through trade, diplomacy, and missionary activity (and, in Egypt’s case, a British occupation in 1882), skeptics of rationalism and scientific reasoning like Jabarti were supplanted by people who saw no discord between reason and religion.

These bureaucrats, scientists, clerics, and journalists were responsible for innovations like theaters of anatomy (in defiance of the Prophet’s injunction against cutting up dead bodies), public-hygiene measures such as quarantine, and efforts to raise pitifully low literacy levels. No matter how much Locke and d’Alembert they read (there was a busy translation movement in the 19th century), Islam’s modern rationalists also saw themselves as the heirs of Avicenna and Farabi. The Egyptian reformer Rifaa al-Tahtawi went so far as to claim that the most attractive features of Western political thought, such as “liberty” and “equality,” had in fact been anticipated by Islam, in the guise of Islamic justice and charity.

Just as Quranic Arabic had released the rational instincts of eighth-century Muslims, so the modern language reflected changing social priorities. The Arabic word hurriya, for instance, underwent significant changes in meaning. In Jabarti’s time, it signified the state of not being a slave; after the British occupation, it came to denote independence from a colonizing power, before acquiring the connotations of personal liberty that it carries today.

The high-water mark of reason in the modern Middle East came shortly before the First World War, when the region’s three most influential countries, Turkey, Egypt, and Iran, underwent rapid social change, from revolutions in favor of parliamentary rule and expanding education—including to women and girls—to the end of harems and slavery. Muhammad Abduh, Egypt’s chief mufti from 1899 to 1905, argued that Islam needed to recapture the rationalism that it had displayed at its inception, and in a phrase worthy of Avicenna declared that human beings were “not created to be led by a bridle.” The mufti also revived the Mutazilite idea that the Quran was created, not eternal, and therefore was a historical document, open to interpretation according to time and circumstance.

But the old slur that had been directed at philosophers like Farabi—that they were essentially Trojan horses for ideas conceived by foreigners—was eventually hurled at Abduh and his fellow reformers, with the difference that those same foreigners were now taking over the region politically. Egypt had been under British rule since 1882. After the First World War obliterated the Ottoman Empire, Britain and France colonized Mesopotamia and the Levant, while Iran and Turkey only kept the powers at bay by westernizing furiously along Roman lines (Mussolini was the model), not Jeffersonian ones.

This interwar period of colonization and authoritarian modernization is key to understanding why Islamic reason is now in the doldrums. It suffered from its association with the supposedly reasonable West, which was at the same time rapaciously colonizing so much of the Arab and Islamic worlds; atavism was the unintended consequence. In the 1960s, Sayyid Qutb, godfather of modern Islamism, lambasted (the long-dead) Muhammad Abduh for pouring Islam into “the foreign mold of philosophy” and for elevating reason to the same status as revelation. Even defenders of a measured Westernization, such as the secular-minded Iranian Prime Minister Mohammad Mossadegh, were rewarded for their political independence with Western hostility and imperial disregard. In 1951, Mossadegh nationalized Iran’s British-run oil industry, and two years later the CIA and MI6 toppled him in a coup. The Western depiction of Mossadegh was familiar enough: He was an unhinged Oriental and impervious to reason.

Only an optimist would claim that reason in the Islamic world is more in evidence now than it was just before the First World War—or even in the 1960s, before the internationalization of jihad, first against the Soviets, then against the United States. Reason, like liberalism, has been a casualty of the pounding and sanguinary course of events, including the catastrophic US invasions of Afghanistan and Iraq. In this light, it is tempting to read Nusseibeh’s stimulating and informative book not simply as a work of intellectual history, but also as a commentary on the vicissitudes of his own public career, which ended in his failure to reshape Palestinian politics. That Nusseibeh recognizes the diminished status of reason in current Islamic thought is shown by his final, rather despairing prognosis: “Given socioeconomic and political conditions in present-day Arab society, a turn of historical proportions is needed to give free rein to the imagination and permit reason to conceive a new course—as happened, so long ago, right at the beginning.”