Over several decades in the middle of the past century, scholars, critics and knowledgeable art lovers realized that the wellsprings of modern art did not all flow from Picasso. Equal in influence were the ideas and works of Marcel Duchamp, the French artist who prioritized ideas over material objects and invented what we now think of as conceptual art.

Today, most critics would probably put Duchamp over Picasso as the preeminent figure in contemporary art. Or, as Francis M. Naumann writes in the lead essay of the catalogue for a new Duchamp exhibition at the Hirshhorn Museum and Sculpture Garden: “Marcel Duchamp is the most influential artist of the modern era.”

Duchamp was not only the inventor of conceptual art but also the animating spirit of pop art and assemblage, and of gestures such as the “detournement” of the 1950s (the subversive repurposing of popular images). He was the ethical paragon of the mainstream avant-garde, and he gave artists permission to revel in alter egos, wry humor and word games, and to perform an ostentatious distaste for “playing the game” that every artist must nonetheless play to make a living.

All these basic lessons about the artist are manifest in “Marcel Duchamp: The Barbara and Aaron Levine Collection,” which features more than 50 works by or related to Duchamp. The Levine collection has been promised to the Hirshhorn.

The Levines are a familiar presence on the Washington art scene, and they have been generous about allowing visitors to explore their Kalorama home, which has become a substantial shrine to the artist. Aaron Levine is a prominent lawyer, and Barbara Levine has served as a Hirshhorn trustee. Now the public can see their collection, too, in a show that touches on all the significant episodes in Duchamp’s magically wayward career, which included long periods of apparent absence from the art world, among them years when he was primarily engaged with playing chess at a professional level.

The show includes an early ink sketch from 1909 that demonstrates Duchamp’s gift for caricature; significant works related to his inscrutable masterpiece “The Bride Stripped Bare by Her Bachelors, Even”; a 1964 edition of one of his most famous “ready-mades,” the Hat Rack; different versions of his Mona Lisa with a mustache (including one without, or “shaved”); and sketches, books, book covers and material that documents his engagement with surrealism, gambling and chess.

In an interview in the exhibition catalogue, Barbara Levine says, “Actually, we hate the word collector,” and Aaron Levine suggests that they pursued works by Duchamp without any particular strategy: “I just was like an octopus with tentacles, grabbing whatever I could.”

With other artists, that approach might yield a haphazard collection, full of holes and oversights. But with Duchamp’s focus on ideas rather than objects, the acquisition of objects is less essential. One needs only prompts or spurs to thinking, talismans that give occasion to contemplate Duchampian concepts. Duchamp himself seemed to acknowledge that in several works in which he created meticulous and idiosyncratic compendiums of his earlier works. One of these projects functions as a miniature museum in a suitcase with reproductions of basic Duchamp reference points, and another is a green box full of facsimiles of his notes for “The Bride” (the Levine collection features both).

The essential collection of Duchamp’s work is at the Philadelphia Museum of Art, which includes the large, broken glass panels of “The Bride” and his last major work, “Etant Donnes,” a surreal, erotic diorama seen through a peephole in a shabby wooden door. But the Levine collection functions like a breviary of the essentials of Duchamp’s challenge to the art world, which began around 1912 with his turn away from traditional painting after being pressured to change or remove the canvas “Nude Descending a Staircase, No. 2” from a key Parisian exhibition. The offense, it seems, was the title, inscribed directly on the canvas, that seemed dissonant with the image, a dynamic, futurist rendering of a cubist figure. The lesson Duchamp learned then was the need for independence, and an aversion to the dictates of “taste.”

From there, he began a lifelong strategy of pushing against the fundamental ideas that had governed Western art for centuries: the belief that art should be original; that it should appeal to the eye; that the artist, rather than the viewer, is the author of the artwork; that the artist’s individual sensibility and personal touch were fundamental; and that art needed to be material. Duchamp invented an alter ego, Rrose Selavy, a woman whose name was a play on the words eros and c’est la vie, or “that’s life.”

He also kept his distance from the gallery world and traditional self-promotion, until his ideas were so famous and so influential that he couldn’t or didn’t want to hide anymore. Duchamp died at age 81 in 1968, as the world was coming apart, and although he can’t be blamed for that, he modeled in his life a fundamental skepticism about received ideas and traditional power structures, a skepticism that was leading people to the streets across the Western world.

So Duchamp is now the reigning god of contemporary art, and true to monotheistic deities, he reveals himself rarely and in riddles. He often spoke and wrote cryptically, a bad habit too often emulated by contemporary artists and critics. Yet he could explain his purposes with perfect clarity. Duchamp said he wasn’t interested in the purely visual, or what he called “retinal art,” yet in the objects he chose for his ready-mades — a hat rack, a bottle-drying stand, a shovel — he celebrated industrial products with uncommon visual appeal. He was indifferent to the idea of an original work, yet was meticulous when making reproductions of his own. He absented himself from the traditional marketing of his art, but supported himself in part by selling a trove of Constantin Brancusi sculptures he had acquired.

These contradictions or quirks are charming in the person of Duchamp but become more problematic in the larger religion of Duchampism. What, in fact, is wrong with retinal art? Isn’t it the retinal that arrests us as we move through a gallery? Working underground may give one considerable creative freedom, but few artists can afford to do so, and working collaboratively and in communion with others has its benefits, too.

Duchamp was said to be charming, witty and vastly intelligent. But contemporary Duchampism can be dreary. When an artist lapses into intentionally hermetic flapdoodle, you know it’s reflexive Duchampism; when you pass by new works in a contemporary gallery and find yourself simply ticking off the conceptual twists in desultory fashion, like solving easy acrostics, that’s degraded Duchampism.

And what of Duchamp’s presence in a major Washington institution? It will enhance the Hirshhorn’s ability to present a coherent history of 20th-century art, and it will be a significant teaching tool. There’s something delicious, too, about the enhanced profile in the nation’s capital of an artist whose fundamental strategy was playful subversion.

That allows us to make an important distinction. Duchamp’s career was a series of provocations, aimed at ideas about art that had never been questioned. It was essentially Socratic, an art made of questions that undermined comfortable truths and destabilized the interlocutor. That is a very different thing than being lied to.

Marcel Duchamp: The Barbara and Aaron Levine Collection Through Oct. 15 at the Hirshhorn Museum and Sculpture Garden. si.edu.

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