ACCORDING TO Hirshhorn Museum and Sculpture Garden director James T. Demetrion, whose institution has just mounted a lavish survey on the past four decades of contemporary art in honor of its 25th anniversary, each work in "Regarding Beauty: A View of the Late Twentieth Century" should provoke -- but not necessarily provide answers to -- the question, "What is beauty?"

He's right about the provocative nature of the exhibition and the open-endedness of its conclusions, I think, but wrong about the question.

"Where is beauty?" is more like it.

"Is beauty in the eye of the beholder," writes associate curator Olga Viso, who organized the show along with assistant director for art and public programs Neal Benezra, "or does it reside instead within the limits of the object beheld?"

The answer, it seems, after touring the 80-plus works that fill the second floor -- some of which repel and some of which attract, some of which are garish and some of which are downright dull -- is neither here nor there. Beauty, like art itself, lies in the ether that both separates and connects the observer to the thing observed. In short, beauty is like the elusive Waldo: It likes to hide between things.

Your mission then, should you choose to accept it, is to smoke it out of its secret lairs, to tease beauty's delicate strands apart from the weeds of ugliness that sometimes mask it, to not be seduced by the merely pretty and to understand that at times the very thing you're looking at is not, as Bob and Doug McKenzie used to say, the beauty part.

Take Felix Gonzalez-Torres, for example, the late conceptual sculptor whose two lyrical works close the show. In "Untitled" (Leaves of Grass), a string of 15-watt electric bulbs hangs in desultory fashion from the wall. In "Untitled" (Aparicion), a stack of inexpensively printed, poster-sized photographs of a dramatic sky sits in the middle of the floor, free for the taking.

As visual experience, both are nice to look at but neither are particularly "beautiful" in that Grand Canyon way. The beauty of Gonzalez-Torres' work then, to the extent that it exists at all, resides less in execution than in an idea. Suggesting an unseen hanger of decorative lights who has prematurely left his Christmas chores undone, "Untitled" (Leaves of Grass) requires an active engagement of the audience in order to complete the art. It is only through contemplation of what is left unsaid that the artist's meditation on death and departure is rendered beautiful -- albeit in the most fragile and subtle way.

Similarly, the themes of artistic generosity and public accessibility embedded in Gonzalez-Torres' photographic giveaways (other works of his have included piles of shiny candy and stacks of poetic, photocopied text) are what transform a rather mundane picture into something beautiful. The truth is that if his take-one-free cloudscape were on sale downstairs in the gift shop, it would not be a huge seller.

Not all works in "Regarding Beauty," however, are so understated. "Milk Run," a stunning light installation by James Turrell in which the viewer must navigate several pitch-black baffles before entering a chamber illuminated by theatrical shafts of fluorescent color, is a case in point. You needn't even be a believer to feel the holiness.

Another example is Beverly Semmes's room-size "Red Dress," consisting of an oversize red velvet shift suspended on the wall by a giant hanger. The garment's freakishly long hem spills onto and across the floor in a wide puddle of vermilion folds that bathe the gallery's white walls in their reflected glow.

In addition to its physical wallop, the work by Semmes, whose sculptural couture was previously featured in a 1996 Hirshhorn "Directions" show, speaks to issues of gender, sexuality, power and social norms. While the more spiritual environment of Turrell's "Milk Run" appropriately belongs to the exhibition's second half -- that devoted to the ineffability of "Intangible Beauty" -- Semmes's "Red Dress" sits squarely in the middle of the show's more problematic first section, which addresses physical beauty as embodied by art history and interpretations of the human figure.

Called "Beauty Objectified," it opens with works by three Italian artists of the mid-century "arte povera" movement. Jannis Kounellis, Giulio Paolini and Michelangelo Pistoletto all use plaster knockoffs of classical statuary -- either blocking a door, facing mirror images of themselves or staring down a heap of painter's rags -- to comment metaphorically (and fairly obviously, I might add) on the obstacles, obligations and opportunities presented to modern artists by the art of the past.

Photographers Cindy Sherman and Yasumasa Morimura perform a similar trick with their meticulous but not humorless reimaginings of such famous masterpieces as Leonardo da Vinci's "Mona Lisa" and Monet's "Olympia."

How strange, though, that talented multimedia artist Matthew Barney is here represented by lifeless still photographs of androgynous characters from his five-film "Cremaster" series (several of which have already been screened at the Hirshhorn; the latest debuted this year at the Walker Art Center). Why show static images instead of the masterpiece for which he is justifiably best-known?

Where "Beauty Objectified" stumbles, though, is in its treatment of gender and race, two hot-button issues in today's society that can't help but spill over into the forum of the arts.

Arguing its thesis that physical beauty today is primarily embodied by the female (as opposed to cults of male and female beauty that existed in antiquity), "Regarding Beauty" virtually ignores the male body, or seems at least to say that the important art of today does so. Is it because so much of its contemporary depictions -- by painters like Paul Cadmus and photographers like Bruce Weber -- is freighted with a homoerotic (and still taboo) subtext?

What few, unashamed images of the masculine form there are in "Regarding Beauty" include two grotesque, cat litter-textured portraits by Lucian Freud of the late fashion designer and performance artist Leigh Bowery in all his naked, paunchy glory. Tellingly, they are relegated to the ghetto called "Difficult Beauty," along with a quartet of alien-looking babies by Marlene Dumas and two tortured views of the female nude by such gray eminences as Picasso and de Kooning.

"Regarding Beauty" also treats the subject of race equally gingerly. Although a few works in the exhibition do examine differing cultural and ethnic standards of beauty (notably the chocolate-and-soap self-portrait busts of Janine Antoni's "Lick and Lather," Lorna Simpson's photos of straight and kinky wigs printed on felt and Rosemarie Trockel's computer-generated glamour head shots), its approach feels glancing at best. The implication is taken that the white, European conception of beauty is still the gold standard, with any variation from that norm an anomaly.

To be fair, "Regarding Beauty" is accompanied by a series of public programs and a handsome catalogue, both of which confront these issues more squarely (although the connection between many of the films and videos I watched in the Media Arts Gallery and the theme of beauty seems tenuous at best).

Despite the fact that the art itself largely skirts some of beauty's thorniest patches, "Regarding Beauty's" organizers Benezra and Viso are to be commended for taking an excursion into a jungle that, by their boss Demetrion's own description, was "daunting, audacious and profoundly difficult."

REGARDING BEAUTY: A View of the Late Twentieth Century -- Through Jan. 17, 2000, at the Hirshhorn Museum and Sculpture Garden, Independence Avenue at Seventh Street SW (Metro: L'Enfant Plaza). 202/357-2700 (TDD: 202/357-1729). Web site: Open 10 to 5 daily. Free admission.

Free public programs associated with the exhibition include:

Oct. 17 at 3 -- Panel discussion: "Beauty: Universal or Culturally Bound?" Ring Auditorium, Hirshhorn Museum.

Oct. 20 at 7 -- Lecture by Dave Hickey, author and University of Nevada at Las Vegas professor of art criticism and theory: "Beauty: Art Without Artists." Ring Auditorium.

Oct. 27 at 7 -- Lecture by Arthur C. Danto, critic and catalogue essayist: "Artistic Beauty and the Intractable Avant-Garde." Ring Auditorium.

Nov. 10 at 7 -- Lecture by Camille Paglia, author and professor of humanities at Philadelphia's University of the Arts: "The Romance of Beauty." Baird Auditorium, National Museum of Natural History, Constitution Avenue at 10th Street NW.

Dec. 8 at 7 -- Lecture by Robert Farris Thompson, author and Yale art historian: "Aesthetic of the Cool." Ring Auditorium.

Jan. 9 at 3 -- Exhibition tour led by art history graduate students: "New Voices: The Last Words on Beauty."

A series of five film and video programs ("Body as Palette," "Body Conscious," "Icons of Beauty," "The Intimate Gaze" and "Natural Beauty") will be screened on a rotating basis in the second-floor Media Arts Gallery throughout the run of the show. Schedules are available at the museum.

Regular weekday and Sunday tours begin at 1 p.m. at the information desk.