Somewhere, where the painters go, Joseph Stella (1877-1946) must be laughing his big, booming laugh.

He befuddles us, no doubt of it. His work is sometimes grand and sometimes grandly goofy. His career in art makes no sense at all.

No wonder Abram Lerner, director of the Hirshhorn Museum and Sculpture Garden, calls Stella an "enigma." The critic Hilton Kramer prefers the term "conundrum." The Hirshhorn's Judith Zilczer, the curator responsible for the 34-picture Stella exhibition that goes on view today, rightly calls the little show "bewilderingly complex."

Stella was a pioneering modernist and a conservative traditionalist. He was a Pointillist, a Futurist, a Precisionist, a Dadaist, a Symbolist--he wears so many labels that finally none fit. Many of his pictures look at once Italian and peculiarly American. Some are tawdry, some terrific, some pompous, some austere. Say what you will about the man, the opposite is true.

Pick half a dozen artists as far apart as possible, say, Kurt Schwitters the collagist, witty Marcel Duchamp, Gino Severini, that bombastic Italian, the American traditionalist William Merritt Chase, the cartoonist Peter Arno and the anonymous designer of corny Hallmark cards. The Stella show calls to mind all six.

It opens with a striking pencil portrait of a Pittsburgh steel worker dated 1908. The style of that picture is 19th-century traditional. Almost as traditional is the 1945 bowl-and-apple still life with which the exhibition ends. The surprises come between.

"Abstraction: Mardi Gras" (1914-16) recalls Frank Kupka's Orphism and the lyrical abstraction of the young Georgia O'Keeffe. "Lotus" (circa 1929) suggests the sort of pictures California hippies painted in the '60s. The nude who pouts so petulantly in "Torso" (circa 1929) would not look out of place installed above a bar. "Profile: Portrait of Helen Walser" (1940) is done in wondrous colors, bright oranges and yellows and soft pastel hues; her pose suggests portraits from the Renaissance while her hairdo and her bodice make the viewer think of a Peter Arno joke.

A number of these pictures seem a little silly. "Serenade: A Christmas Fantasy" (1937) is the silliest of all. It features, it really does, a starry sky, a nightingale, an iris and a holly branch, an ox, an ass, the dove of peace and the sort of gothic window found in Christmas cards.

"The Artist," Stella wrote in 1921, "wants to have the same freedom of movement that he enjoyed when he was left alone as a child." Stella never lost it. He played throughout his life.

He was born in Muro Lucano, near Naples, in 1877. "I thank the Lord," he wrote, "for having had the good fortune to be born in a mountain village . . . My eager art took its first flights there in that free, light-filled radiant space . . . I remember the bursting out of my art in early childhood. It was like a sudden flash of light, thunderous as some celestial torrent." Much of Stella's painting, like much of his prose, is over-operatic.

He had finished school in Naples when, at age 18, he moved with his family to the Lower East Side of New York. Stella studied briefly with William Merritt Chase at the Art Students League, and a number of his early works, especially the portraits, recall the gritty realism of the Ashcan School. But no single style held his interest long. Stella spent 1909 to 1912 in Italy and Paris, where he fell in love with Futurism, Cubism and other modes of modernism. Therafter he preferred to blend this style with that.

Yale University's "Battle of Lights, Coney Island, Mardi Gras" (1913-14), perhaps his finest painting, is a Futurist extravaganza touched by Cubist shatterings and predictions of Pop Art. Two oil studies for that picture, both pointillist, are in the Hirshhorn show.

"The Bridge" (1922), at the Newark Museum, portrays the Brooklyn Bridge and hymns, as it does so, cathedrals and machines. Three sketches for that painting are in this exhibit. No two are alike.

Pietro Lazarri, the Washington painter, once saw Stella showing off in a Greenwich Village teahouse. Lazarri remembers him "glowing and round faced, balding head going to a point, his huge dome pierced by two black mobile eyes of liquid lava . . . In the semi-darkness of the shop, Stella emerged as a man on fire, his arms gesticulating and chasing space, as the arms of an infuriated divinity." Man Ray, less impressed, remembered that the "very fat" and "very vain" Stella "considered himself a Don Juan." One feels in those descriptions the mood of Bohemian haunts.

Stella's friends included Gertrude Stein, Marcel Duchamp, and the composer Edgar Vare se. Those stalwarts of the avant-garde loved contradictions, jokes, violations of propriety, sudden shifts, surprises. Stella never let them down. He plays just such Bohemian games on those who see his show. He embarrasses his viewers, he delights them and he jolts them. Though he was no master, he gets the last laugh.

The Hirshhorn exhibition closes July 17.