On January 7, 2015, the French president François Hollande, speaking in the wake of the Islamist killings in his nation that day, said it was “the Republic as a whole that has been attacked.” Hollande claimed that “the assassins were targeting” not just a few individuals, but the Republic’s core values: free expression, creativity, pluralism, democracy. He vowed that France would defend these values by fighting “against terrorism and fundamentalism.”

Almost immediately, some on the left recoiled from such sentiments. The president had implied that there was a fundamental clash of civilizations, which the jihadists may well have hoped to foster—but why should critics of a rapacious capitalism fall in line with the Eurocentric version of that bloody project? After all, Hollande represented a regime that had instituted a kind of de facto apartheid, concentrating several generations of immigrants from Northern Africa, many of them young and unemployed, in suburban banlieues. “The Republic” was hardly an innocent in these events.

In France, one commentator remarked afterward that Hollande, although a member of the French Socialist Party, was in practice a “social-liberal,” a label meant to insinuate a feeble acquiescence in the inequities generated by unfettered market forces. Still other critics on the left went on to resurrect the familiar assertion that there exists an existential divide between liberalism and socialism. Among implicitly socialist academics, the existence of such a divide is sometimes signaled, without evidence or argument, by the sneering deployment of the term “neoliberalism,” as if this were the default—and perhaps only—form of liberalism on offer today.

Slavoj Žižek put the accusation this way: “So what about the core values of liberalism: freedom, equality, etc.? The paradox is that liberalism itself is not strong enough to save them against the fundamentalist onslaught. Fundamentalism is a reaction—a false, mystifying reaction, of course—against a real flaw of liberalism, and this is why it is again and again generated by liberalism. Left to itself, liberalism will slowly undermine itself.” Why? Because it lacks any convictions whatsoever. Liberals in the West, Žižek declares, are like “the Nietzschean Last Men, immersed in stupid daily pleasures” and no match for radical Muslims with their fighting faith: “Those who do not want to talk critically about liberal democracy should also keep quiet about religious fundamentalism.”

Žižek’s remarks reminded me of an essay by the Anglo-American intellectual historian Larry Siedentop that ought to be better known. Entitled “Two Liberal Traditions” and published in a 1979 Festschrift for Isaiah Berlin, edited by Alan Ryan, the essay focuses mainly on the French tradition, which Siedentop helpfully distinguishes from the Anglo-American one. While the empiricists of the British liberal tradition elaborated a problematic kind of “possessive individualism,” French liberals like Benjamin Constant, François Guizot, and Alexis de Tocqueville, by contrast, were pioneering proto-sociologists who studied the beliefs and conduct of human beings in social settings (rather than, say, trying to view them as self-sufficient actors seeking practical advantages and protection from society, as Hobbes had done).

Siedentop starts his 1979 essay with a bang: “Nothing reduces the value of discussion about modern political thought more than the contrast commonly drawn between ‘liberalism’ and ‘socialism.’” A rote reiteration of the contrast, he continues, “ignores the extent to which modes of argument and themes which are usually assigned to ‘socialism’ formed an important part of liberal thought” in the wake of the American and French revolutions.

Take the theme of equality. Socialists of all stripes aim to create a more egalitarian society through economic and social reforms. But the 18th-century Americans who declared the nation’s independence and the revolutionary thinkers who drafted the world’s first democratic constitution in Paris in 1792 and ’93 pursued a similar ideal before socialism, as a movement, even existed. As Siedentop puts it, “the fundamental or root concept of liberalism is equality, and its commitment to liberty springs from that.” Danielle Allen makes a similar point in Our Declaration, her recent book on the Declaration of Independence, which focuses on a passage that Abraham Lincoln also held dear: “We hold these truths to be self-evident, that all men are created equal….” Why, then, do many socialists so deeply misunderstand the provenance of the core values they actually share with liberals? And why do some liberals so deeply distrust professed socialists and assume they must be illiberal?

It is, in part, to correct these mutual misunderstandings that Siedentop has devoted his career. He worries that “in the eyes of Islamic fundamentalists, and indeed in the eyes of not a few in the West,” Žižek among them, “liberalism has come to stand for ‘non-belief’—for indifference and permissiveness, if not for decadence.” And it is, in part, to present Western liberalism as a fighting faith, with substantive moral commitments, that Siedentop has written his new book, Inventing the Individual: “If we in the West do not understand the moral depth of our own tradition, how can we hope to shape the conversation of mankind?”

* * *

For many years a research fellow at Keble College, Oxford, Siedentop was born and raised in Michigan. He received his BA from Hope College, one of the rare liberal-arts schools that, perhaps because of its ties to the Reformed Church in America, remains dedicated to conveying to students what its website calls “the foundational commitments of the historic Christian faith.” After getting an MA from Harvard, Siedentop immigrated to England, where he completed a dissertation at Oxford on the French thinkers Joseph de Maistre and Maine de Biran under the supervision of Isaiah Berlin.

Siedentop has become one of the world’s experts on French liberalism. And now, after publishing widely reviewed books on Tocqueville and on democracy in Europe, he has produced what amounts to a high-altitude survey of Western ideas, meant to show that the ideal of the autonomous individual and the fact of a pluralistic civil society are both in important respects outgrowths of Christianity.

This isn’t exactly a novel claim. Hegel argued for a somewhat similar understanding in his lectures on the philosophy of world history, as did Nietzsche, in a more critical vein, in The Genealogy of Morals and other works. In effect, Siedentop is resurrecting a perspective that has fallen out of fashion, and not just because it is blatantly Eurocentric.

Even more surprising, in order to make his case, he has resurrected a style of inquiry that is no less unfashionable: philosophical history. This was a form of writing, aimed at fellow intellectuals rather than professional scholars, that had flourished in Europe in the 18th and early 19th centuries. Voltaire and Rousseau both offered sweeping, polemical, and highly speculative accounts of large stretches of human history. Their approach was taken up by Condorcet and Hegel, and then by Siedentop’s avowed inspiration, Guizot, whose General History of Civilization in Europe grew out of lectures he gave in Paris that were attended by Tocqueville. (Karl Marx was also influenced by Guizot’s stress on class conflict as the motor of progress.)

In this hybrid form of inquiry, the philosophically minded historian organizes various facts about the past into a comprehensive story about ideas, in the hopes of understanding better the ethical and political implications of the past for the present. As Siedentop explains, his new book rests on the assumption “that if we are to understand the relationship between beliefs and social institutions—that is, to understand ourselves—then we have to take a very long view.” He aims to “tell a story about how the ‘individual’ became the organizing social role in the West—that is, how the ‘civil society’ which we take for granted emerged, with its characteristic distinction between public and private spheres and its emphasis on the role of conscience and choice.” Like Charles Taylor in his similarly sweeping (and similarly selective) philosophical history Sources of the Self, Siedentop in this way hopes to leave his readers better equipped to answer some key philosophical questions: What should I do? What may I hope for?

* * *

Unlike Taylor, who in Sources of the Self focused on the centuries after the Renaissance, Siedentop begins his narrative in ancient Greece. Although classical Athens is often represented as a distant yet admirable precursor to modern liberal societies because of its democratic regime and its hospitality to philosophical inquiry, Siedentop prefers to accentuate the illiberal aspects of the city, following here in the footsteps of Fustel de Coulanges, a French historian active in the second half of the 19th century. The ancients, in this telling, “privileged the identity of the family and the polis over the individual…cast some humans as by nature slaves or ‘living tools,’ and…presented the higher faculties of the mind as making possible a liberation from the physical world into a superior realm of pure ideas.” In the classical world, “the contrast between ‘barbarians’ and citizens was extreme. The usual presumption remained one in favour of inequality.”

By contrast, “Christian insistence on the equality of souls in the eyes of God reversed that presumption.” But because it took centuries for the implications of that view—many of them quite unintended—to become clear, Siedentop devotes the heart of his book to a detailed recounting of how the advent of Christianity overturned key classical beliefs, from the early church to the conciliar movement of the 14th and 15th centuries.

From the start, he claims, the Christian joining of equality with reciprocity became the basis of a new worldview: “Thou shalt love thy neighbor as thyself.” (He neglects the Jewish and Socratic sources expressing similar sentiments.) Paul, Siedentop argues, was an authentic revolutionary who insisted on the moral equality of all human beings, master and slave, man and woman. The martyrs required no feats of dialectical reasoning to become heroes of faith and conviction. Early Christian monasteries forged a new identity within pioneering voluntary associations, founded “in individual acts of will.” Within the Christian community, “work acquired a new dignity, becoming even a requirement of self-respect.” And “in contrast to the segregated spaces of the ancient city, the Christian population of the cities began to share the same spaces, hearing the bishops’ ex cathedra words in the basilica or principal church,” with rich and poor participating in the same rites.

All of these emergent norms were helpfully codified by the Roman Catholic scholars who created the first universities in the West, elaborating a tradition of inquiry that some living philosophers (Alasdair MacIntyre, for one) still consider our richest resource for constructing new forms of community. It was founded, as Siedentop puts it, “on individual morality and self-discipline, rather than on brute force and mere deference.” At the same time, the medieval popes transformed the church into an independent, “self-governing corporation, a quasi-state” claiming exclusive sovereignty over spiritual matters. “The example of the church as a unified legal system founded on the equal subjection of individuals thus gave birth to the idea of the modern state”—and also to the creation in the West of numerous civil as well as religious courts.

“Little wonder that a Byzantine visitor to Western Europe in the early fourteenth century was impressed by one thing more than anything else: the omnipresence of litigation, courts, and lawyers,” writes Siedentop, marshaling a telling anecdote. The startled visitor, he remarks, “was, in fact, encountering the attempt to create the rule of law on a new, individualist basis, spreading from the church into the secular sphere.” One important result, he argues, was the elaboration of “a ‘democratic’ will on the basis of equal rights, that is, on civil and political liberty.” Another was the rise of an independent civil society, because once an intuitive moral commitment to “equal liberty” was widely shared, it could be “turned against the church itself, creating misgivings that eventually led to a principled rejection of any coercive or ‘privileged’ role for the church” within secular society.

It would be easy to quarrel with many details in this account, and to qualify or reject some of the points that Siedentop makes. He is not a cautious writer; he’s interested in a few big ideas, and he hammers them home with brio. He tends to minimize the illiberal features of Western Catholic societies, which sometimes produced problems (to put it mildly) for pagans, Jews, and Muslims. He mentions developments in the Eastern Orthodox tradition only in passing and has little to say about the rise of Islam and its impact on medieval Europe. A comparative study of the social implications of different religious traditions (of the sort that Max Weber undertook in his magnum opus Economy and Society) would be required to confirm that the West has been as uniquely hospitable to the evolution of core liberal values as Siedentop implies. In general, he is too grudging in acknowledging other scholars who have plowed these fields, mostly ignoring recent historical research and saying nothing about philosophers like MacIntyre, Taylor, and Marcel Gauchet—or about Michel Foucault, whose last books dig deep into antiquity to show the roots of how we in the West have come to take “care of the self.”

Despite its manifold defects, Siedentop’s narrative is briskly readable, and the basic point seems right. For better or worse (Nietzsche thought for worse), beliefs widely popularized by the Catholic Church in late antiquity and the Middle Ages have become, in their civil guise, a core part of the secular West’s moral fabric.

* * *

Strangely enough for an expert in modern political thought with an interest in current affairs, Siedentop ends his story before the Renaissance begins—a deliberate provocation, but also a missed opportunity to tie the book’s themes together with some similar ones broached by his scholarly work on French liberalism.

As Siedentop explains in “Two Liberal Traditions,” 19th-century liberals like Guizot were keenly aware of the Christian roots of their own convictions. In the wake of the French Revolution, they had begun to ask “what kind of authority would be compatible with greater social equality.” While the Utilitarian liberals in England took needs as given and focused on “achieving the most ‘rational’ or desirable balance of satisfactions,” French liberals assumed that needs were defined by social settings and thus were historically variable. They identified several key factors for the analysis of social change: the division of labor, the distribution of property, education, and social mobility. “Thus, it was the French liberals,” not Marx, “who invented the concept of a social—as distinct from a political—revolution,” Siedentop writes. For the French liberals, the rule of law was a necessary but insufficient condition to meet the challenge of democratizing societies and emergent markets. Even more crucial was what some of them called “free mœurs“—and that required inculcating a set of shared secular beliefs and “habits of the heart” (in Tocqueville’s phrase) through public education, participation in voluntary associations, and shared patriotic rituals.

According to Siedentop, the mores at stake in secularism rest “on the firm belief that to be human means being a rational and moral agent, a free chooser with responsibility for one’s actions. It puts a premium on conscience rather than the ‘blind’ following of rules. It joins rights with duties to others.” Therefore, a secular society ought to reinforce these emancipatory beliefs and in this way renew, and revise, “the central egalitarian moral insight of Christianity.”

In defense of such substantive convictions, French liberals, along with their socialist successors, became self-conscious representatives of a form of secularism that could be aggressive to a fault. Some endorsed secular mores as an all-encompassing rival to and replacement for Christianity. This characteristically French form of laïcité is unapologetically based on a founding exclusion: the banishment from the public sphere of all religious movements and institutions that refuse to draw a sharp line between theology and politics. At the same time, and paradoxically, its own core commitments—to liberty, equality, fraternity, and free expression—are transformed into a kind of civil religion, just as Rousseau had recommended. (The French revolutionaries even staged a so-called Festival of the Supreme Being, in an effort to impose a new, frankly secular form of faith.)

No wonder that Tocqueville called the French Revolution a religious event—or that this form of crusading, exclusionary secularism finds itself locked today in irreconcilable conflict with illiberal religious groups that insist on the rightness, for everyone, of their doctrines, and in all spheres, both public and private.

But an aggressive (and sometimes frankly intolerant) form of laïcité is not the only kind of secularism that exists: America’s approach to religious freedom aims to be inclusive rather than exclusionary. And the virulent anticlericalism that has been a recurrent feature of the French liberal tradition does not lack for critics. Jürgen Habermas recently suggested that “the substance of the human” can only be rescued by societies that “are able to introduce into the secular domain the essential contents of their religious traditions.” I assume that Siedentop would more or less agree. Open-minded secularists should aim to be as tolerant as possible—and that includes tolerating religious fundamentalists, as long as the fundamentalists can also accept peaceful coexistence with secularists. That sounds insipid, but it’s easier said than done. Inclusiveness is hard to achieve, as the painful history of both liberal and socialist regimes shows: A truly open society must overcome any and all arbitrary exclusions of people from participation in politics and civil society because of a lack of property or education, or for reasons of race, gender, or religious belief.

Additional problems sometimes arise when liberal secularists, faced with systems of belief that make rival claims to universality, are asked to justify the applicability of their beliefs. Why should the value of free choice trump the values of religions that abhor freedom of choice? As the social anthropologist Ernest Gellner noted in Conditions of Liberty: Civil Society and Its Rivals, “the code of cognitive conduct which has emerged with Civil Society, which separates facts and values, unfortunately prevents us from terminating the regress of justifications.” (Robert Frost made a similar point when he quipped: “A liberal is a man too broad minded to take his own side in a quarrel.”)

But the most intractable problem for the liberal secularist arises not from law-abiding fundamentalists, who are willing to live and let live so long as they are permitted to practice their religion without fear, but from terrorists and groups who violently assault—and explicitly repudiate—a society of equals that includes those whose beliefs they disagree with, calling into doubt the viability of a modus vivendi based on mutual tolerance. (For this reason, I think François Hollande has been wrong in the aftermath of the Paris massacre to continue conflating terrorism and fundamentalism, and to speak of a “reconquest” of France’s minorities through reforms of the secular school curriculum.) In any case, secularists today face challenges not only from the Islamists of ISIS and Al Qaeda, but also from militant anti-Semites and anti-immigrant groups. The secular pluralist in such circumstances is faced, like it or not, with a conundrum: to defend an open society requires not tolerating the murderously intolerant.

* * *

Siedentop’s story of the rise of liberalism is, by design, not just a history of ideas; it is also an invitation to reflect on the core convictions that many of us have internalized. As a professor who teaches and writes about political philosophy, I have spent much of my adult life lamenting the pusillanimity of some mainstream liberal politicians (such as Hollande before the events of January 7); protesting wars ostensibly fought to defend liberal values, from Vietnam to Iraq; and criticizing those liberal theorists who ignore the socioeconomic sources of inequality, which constrain a full realization of the key ideals shared by most liberals and socialists.

But skeptical though I try to be about the various prejudices that I absorbed growing up in the Midwest (in a liberal home with a fiercely introspective Lutheran mother and a father who revered trade unions, egalitarian economic policies, and the democratic poetry of Walt Whitman), I cannot help but take pride in my ability to think through alternative forms of life—a process that would be perfectly pointless if I thought I had no real choice in the matter. In this way, I generally assume that I am an autonomous individual who enjoys, and should enjoy, a certain measure of self-evident freedom, both in how I think and how I behave.

Liberal institutions, from our primary schools to our prevailing forms of contract law, by design reinforce such typically modern assumptions about the liberty of the individual and the salience of free choice. Presumably, that was one reason I felt so viscerally outraged by the attacks in France, as if they were an attack on me. And in a sense, they were: a deliberate attack on several core convictions that I happen to share with François Hollande, label him what you like.

Larry Siedentop has written a philosophical history in the spirit of Voltaire, Condorcet, Hegel, and Guizot. Serious scholars of history will always pick holes in these works. Yet at their most cogent and pointed, such frankly polemical metanarratives of human history help us to understand better not just the history of the present (to borrow a phrase), but also ourselves.

At a time when we on the left need to be stirred from our dogmatic slumbers, Inventing the Individual is a reminder of some core values that are pretty widely shared. An existential divide shouldn’t separate socialists and liberals. In principle, as Siedentop reminds us, we belong on the same team, fighting to realize a pluralistic society of equals, and the commitment to liberty—and freedom of religion—that properly springs from it.