Does It Take a Village? Or riding lessons and a Swiss au pair? Are you more likely to name your daughter "Britney" or "Dylan"? No matter what your answers, I can still predict you'll vigorously applaud the following sentiments: The well-being of children is sacred. Each child's full potential is a birthright, not to mention a precious national resource. To violate a child's sexual innocence is, of course, to commit a crime against nature. The death of a child marks the far boundary of grief.

When it comes to children, our tolerance for moral ambiguity or Po-Mo showboating quickly reduces to zilch. Even the great nihilist James Joyce once allowed that in a life of endless uncertainty, a mother's love "may be the only true thing." But what if all these feelings were merely conventional, and not natural?

In 1960 the French historian Philippe Aries published Centuries of Childhood, a book whose once-controversial thesis—that in medieval society "the idea of childhood did not exist"—took aim at every piety regarding the unique status of children. Writing in that inimitable—though frequently imitated—"she mates, she kills" style of high French theory, Aries argued that, up until roughly the 15th century, childhood was not perceived as a distinct phase of human life; instead, children were perceived as little more than Mini-Me's. To us moderns, with our nuclear, bourgeois, and sentimental family values, Aries' medieval home appears almost totally alien. Children intermingled fully with adults, wore the same clothes, played the same games. They were not regarded as sexually innocent and thus psychologically delicate and were never segregated away from the adult pupils more common in French schools at the time. Parents did not bond deeply with young children, as so many died in infancy or soon after, and by the time their children hit 8 or so, parents often fostered them in other people's homes to work as domestic servants. Aries' most famous evidence is the iconography of the Middle Ages, which depicts children as adults, only smaller. In our own world of mass marketing, universal schooling, and hypervigilant parenting, we've come to isolate virtually every six-month span in a child's life as a separate and unique epoch, each with its own set of tastes and developmental milestones.

Centuries of Childhood remains one of those books that, virtually on contact, sets the mind on fire. Re-reading it today, one sees immediately why it influenced specialists and generalists alike while gaining a substantial readership among the broader public. But if Aries' idea keeps up a phantom half-life outside the academy (a surprising number of my lawyer friends still know that in the Middle Ages, kids were thought of as miniature adults), its influence within the academy is hard to overstate. By arguing that something as seemingly natural as parental affection is in fact an historical novelty, Aries helped initiate a now-inexorable trend in the humanities: Everything is interpreted as a product of culture—as governed by status relations or economic necessity, and not by something more timeless and intrinsic, like human affection, nature, or biology. Thus Aries helped give birth to Foucault and his famously macabre pronouncement that "Nothing in man—not even his body—is sufficiently stable to serve as the basis for self-recognition or for understanding" and to all Foucault's American acolytes, whose new historicism, culture studies, and post-colonialism now cut through virtually every academic discipline.

So, should it matter if Aries was wrong?

As it turns out, Aries has inspired a second cottage industry—the anti-Ariesists, most notably Steven Ozment at Harvard and the English historian Nicholas Orme. Orme has just published Medieval Children, a book written with no other apparent purpose than to totally, finally, once and for all demolish Aries' thesis. "It cannot be over-emphasized that there is nothing to be said for Aries's view of childhood in the middle ages," Orme writes (in the warmest prose of the entire treatise, if this gives you a clue), adding: "Aries's views were mistaken: not simply in detail but in substance. It is time to lay them to rest." Anyone leafing through Orme in search of a Perry Mason moment—the evidence brandished, Aries refuted!—will be disappointed, however. Orme and Aries never really go toe-to-toe, as Orme has chosen a completely separate data set—medieval England, in place of Aries' medieval France—and attempted to demonstrate that there were in fact children as we moderns understand the term. Moreover, his refutation is mostly stylistic and interpretive: Orme presents himself, in every respect, as Aries' opposite. Where the Frenchman was oracular and tendentious ("Boys were the first specialized children," announces Aries at one point), the English historian is phlegmatic and common-sensical. ("Boys, after all, will be boys, and girls will be girls," Orme concludes one chapter on how medieval children played with one another.) Everywhere Aries insisted on making the Middle Ages seem alienating, even borderline inhuman; Orme everywhere stresses continuity, softening differences wherever possible, as when he uses the unlikely expression "child-friendly" when describing the medieval church.

Nowhere is the difference between Aries and Orme more pronounced than when they write about sex. "One of the unwritten laws of contemporary morality," Aries wrote, "the strictest and best respected of all, requires adults to avoid any reference … to sexual matters in the presence of children. This notion was entirely foreign to the society of old." Aries' example is unforgettable: the immodesty with which the royal court played with young Louis XIII, specifically with the young prince's newly discovered erections. After throwing in a couple more examples, Aries concludes, "[T]he idea did not yet exist that references to sexual matters … could soil childish innocence … [as] nobody thought this innocence really existed." This is pure Aries: the unrepresentative example—after all, it's good to be the king, no?—stretched to meet the needs of the vatic conclusion. Meanwhile, Orme sees so strong an analogy with the past that he reverts to anachronism, repeatedly using the term "abuse" to describe adults' sexual activity with children, even though it had no such connotation in the Middle Ages. (When, in the 12th century, a group of visitors to a monastery joke at the reputation monks have for "lying on" boys, the abbot blushes while the visitors go outside to share a good laugh. No one wigs out and frantically calls in the case worker or the local DA.)

In the end, Orme only tackles Aries' infamous punch line about medieval children's nonexistence, and not Centuries of Childhood itself. For Aries' book is less about the concept of childhood than the emergence of universal, regimented, and standardized schooling and the loss of a public sociability Aries takes to have been endemic to medieval society. In the Middle Ages, Aries argues, "[p]eople could not imagine a society that was not cemented by public recognition of a friendship"; and, no longer able to hide a certain affection for the Middle Ages, he later adds, "[T]he modern way of life is the result of the divorce between elements which had formerly been united: friendship, religion, profession." Family life—in particular, the immense emotional space taken up by raising one's children—is now meant to compensate for a loss of a more spontaneous public fraternity, but, Aries strongly hints, it falls painfully short.