Nobody can deny that “Century of the Child: Growing By Design 1900-2000,” at the Museum of Modern Art, is a great looking show. The ambience in the galleries is cool and bright, with scores of children’s books, toys, furnishings, and baubles, many by the legendary movers and shakers of twentieth-century art and design, boldly arranged in big, white rooms. The darker themes explored here—including the toll that war and poverty have taken on the lives of children—do little to disrupt the general sense that museumgoers are being invited to have a jolly good time. The bourgeois-bohemian kids’ stuff by Charles and Ray Eames and countless other artists acts as a sedative, so that the more disturbing works on display, among them the Art Workers’ Coalition poster of children massacred at My Lai, hardly register at all. Juliet Kinchin, the curator in charge, is tossing objects and ideas in the gallery air, juggling stylishness and high-mindedness with an evenhanded elegance that has been a specialty at MoMA at least since the “Machine Art” show opened in 1934. “Century of the Child” is wonderfully suggestive. But what it all adds up to—or whether it adds up at all—is another matter.

I have to admit I feel a bit of an ingrate, complaining that a show this beguiling doesn’t make much sense. But questions about the exhibition’s most fundamental assumptions may occur to museumgoers, even as they are happily immersed in a splendid display of early twentieth-century kid’s books or the appealingly quirky objects that African children have made in recent years with materials collected in a village dumping site. I found myself wondering about the basic premise, namely that in the twentieth century children had a more central role in shaping human experience than in any previous time. In what sense is this true? Couldn’t a strong argument be made that the nineteenth-century was the century that really focused on the child, if that focus is measured in terms of a heightened awareness of the importance of children’s books and toys and education, and a growing attention to the injustices of child labor that we find, to name but one example, in the novels of Dickens? Isn’t the centrality of the child’s experience really a discovery of the romantics, and therefore perhaps even a late eighteenth-century discovery? How could the century of the child be a century in which neither Rousseau nor Wordsworth lived? And if the real point of the show is that the organizers are quite simply delighted to find children everywhere in twentieth-century civilization, couldn’t an equally beguiling show be devoted to the child in Ancient Egypt? I know I’m being a bit of a devil’s advocate. Of course there is some truth to all the old stories about a pre-modern period when children were seen but not heard. But one of the paradoxical effects of “Century of the Child” can be to make you think about children in any number of centuries. When “Century of the Child” focuses on children as victims of violence perpetrated by adults, I can’t help thinking of the children represented in Renaissance and Baroque paintings of the Rape of the Sabine Women and the Massacre of the Innocents. And there may be nothing in “Century of the Child” that evokes the joys of a person’s early years better than Breughel’s great painting, Children’s Games.

Kinchin, a curator in the museum’s department of architecture and design, definitely knows how to install a show. She already has another sleek disquisition on the interface between modern life and modern design under her belt, MoMA’s invigorating 2010 “Counter Space,” about kitchen utensils and design. But that show, while nowhere near as big as “Child of the Century,” raised related questions about the museum’s by now nearly century-old obsession with the relationship between function and form. There has been a tendency at MoMA to imagine that the simplest objects—a simple mixing bowl, a simple stuffed animal—are especially forthright and honest, their use bringing us closer to some essential truth about experience. But is the person who mixes a cake in the best-designed Scandinavian mixing bowl actually a better person who is mixing a better cake in a better way? Do we really want to go down that road? And when the curators at MoMA embrace more heavily ornamented objects—the intricately patterned textile, the crazily shaped vase—they seem to want to find some truth there, too, some idea about the philosophical virtue of going over the top. The problem, as I see it, is that function and form are not necessarily related, at least not in any way that can be succinctly or indeed systematically described. Of course, one of the things that MoMA has been very good at doing in its design shows is changing the subject just when there’s some danger that the serious questions may finally be asked. There’s a bait-and-switch aspect to MoMA’s approach to the decorative arts. They pull us in with objects that are extraordinarily handsome; they massage our egos by assuring us that there’s some deep sociological or philosophical reason for our gawking at the perfectly designed office chair or wine glass; and then, when the fancy explanations begin to look a little too fancy, they let us off the hook by assuring us that it was all in good fun. I suspect that was how museumgoers responded in 1949 to “Modern Art in Your Life,” an extravaganza organized by René d’Harnoncourt and Robert Goldwater that sported a catalogue with a brilliant cover design by the great Paul Rand.

The virtues and vices of “Century of the Child” are old-fashioned virtues and vices for the Museum of Modern Art. Juliet Kinchin is a traditionalist of a sort, practicing the museum’s fundamentalist faith, insisting that forms have a legible meaning. Especially in its first half, “Century of the Child” is definitely a feast for the eyes. Who can resist the wonderful cottage-style 1912 dollhouse by Jessie King, or Josef Hoffmann’s toy factory, or Giacomo Balla’s child’s wardrobe, or Bruno Taut’s colored glass building blocks? But a strong argument can be made that these objects do not reflect a modern vision of childhood in particular so much as they are examples of modern artists using the forms that come naturally to them. The basic problem with “Century of the Child” is that cause and effect become so hopelessly conflated that you can’t ever be sure if it’s children who are changing the face of modern art and design, or artists and designers who are changing the face of childhood. Did the bold forms and bright colors of turn-of-the-century educational materials made for children help to shape the imaginations of modern artists? It’s possible. Or was it a sophisticated taste for bold forms and bright colors that shaped our ideas about what children want? That’s the chicken-and-egg question that percolates beneath the surface of the entire show. There’s fun to be had here. But when “Century of the Child” gets serious it risks becoming a little silly.