For viewers aware of the art of recent decades, most of the collection will be deeply familiar. The majority of the 24 artists are established in art history's pantheon of the 1960s and '70s -- Dan Flavin, Donald Judd, Sol LeWitt, Richard Serra. Big art by big names. Many works are either huge or serial installations consisting of numerous elements, hence Dia's need for this structure of 300,000 square feet of interior space -- a quarter million of it for galleries -- to display its collection. Attention shifts, then, to the placement and installation of their works and to the architectural environment.

The main building's series of sawtooth skylights illuminates the works with clear light bouncing from the river. The light is further reflected by blond maple flooring, another treasure discovered within the brick walls. Robert Irwin's master plan for the renovation of the factory, working with the architects of OpenOffice, piggybacked onto the facade a small vestibule. Like the low-ceilinged entrance at the Guggenheim Museum in Manhattan, passing through this small room intensifies the experience of expansion when emerging into the huge, radiant gallery.

The floor plan combines room-sized galleries and great halls, and the sense of being within a structural grid is underscored by Irwin's geometric pattern of fenestration juxtaposing translucent and transparent panes. Scanning these acres of right angles brought to mind the New Yorker cartoon of a corporate executive speaking into his desk intercom, "Ms. Jenkins, would you please bring a round object into my office?"

The proliferation of squares logically dotting the space includes Judd's slightly varied 15 unpainted plywood boxes (and that's just one of his eight works on view); LeWitt's Wall Drawing #1085 (1969), an array of 96 drawings each ca. 40 inches square (there are also five other works by LeWitt, one made up of 56 variations of steel cubes); and Andy Warhol's Shadows (1978-79), 72 large (76 x 52 inch) black paintings with an identical abstract shape in different hues installed contiguously like a rhythmic band of decorative wainscoting around a very large vacant hall. The tick-tack-toe effect is less dizzying than enervating.

Even the vitality of irregular crunches and popping hues of John Chamberlain's 16 sculptures strewn over a long gallery take on an orderly, mechanical, feel. One expects respite in an enclosed room of Agnes Martin's quiet linearity -- but then almost chokes on the suffusion of 15 big square paintings done in cotton candy colors.

An antidote to all these exercises in installation excess is the analytical tautness of Serra's trio of experiential Torqued Ellipses. The impact of their compressed caverns are further heightened by their placement within a narrow corridor.

But the sense that many of these massed objects are playing strong silent types comes not only from the works' familiarity, but because they are utterly decontextualized. The only thing on view other than the works themselves are wall labels listing artist, title, date. The curatorial M.O. is the old-fashioned formalist idea that "the art speaks for itself." It doesn't. It speaks through us, and thus has many possible voices, and is part of history. In relation to the values of our own time, of economic contraction and acute awareness of global duress, these works shout "conspicuous production."

By contrast, when they were made, these abstractions' bold scale was deeply radical, inspired by big refusals of expressionist juice and touch, overt visual pleasure and poetic metaphor. The Dia collection harkens back to a decade when the convergence of strong fiscal growth, the largesse of Great Society programs, increasing support for civil rights, anti-Vietnam war protests, and myriad forms of personal and sexual liberation made such artistic innovation on a large scale a cultural manifestation of the utopian belief that "anything is possible."

This may explain why Postminimalism's enactment of the chaos and conflict of the late '60s' years of political assassinations and anti-Vietnam tumult, of anti-form and disarray, has been relegated to a back corner. There, it's a thrill to discover in an alcove Joseph Beuys' messy piles in an installation that was a setting for one of his anti-war Coyote performance pieces. Another historically important, rarely exhibited work is Serra's 1967 scatter piece of rubber latex and rods.

And another back-room boy here is Robert Smithson, who in 1972 recalled his skepticism of Minimalism, saying that, "The very construction of the gallery with its neutral white rooms became questionable." Significantly, works by Smithson did not enter the collection until Nancy Holt's gift of the Spiral Jetty in 1999 became an offer Dia could not refuse. The Lannan Foundation then purchased the Smithson works on view at Beacon as a long-term loan. Three of Smithson's four sculptures here are rarely seen "nonsites," works that contain geological matter (loose gravel, salt crystals or sand), from specific places and juxtapose hard mirror panels to their loose disarrays.

The grittiness of this rear building's brick walls and concrete floor does correspond well with Beuys' and Smithson's piles, the official reason for these works' placement. But an effective installation not only makes each work look good, but collectively tells a story. Walter De Maria, one of the artists still alive and thus given the choice of his space, staked out a gallery front and center for his floor-bound stainless steel outlines of circles and squares. It is twice as wide and three times as long (300 feet) as the rear spaces allotted to Beuys and Smithson.

One wonders why the parents at this institution, director Michael Govan and curator Lynn Cooke, didn't referee their charge's land grab instead of allowing the placement of works to imply a topsy-turvy art history, contrary to each artist's achievements and impact. The misleading effect of that contrast, already seen in the press, is to encourage a downgrading of Smithson's achievement by the uninformed.

And was it an innocent coincidence that no pictures of works by Smithson were available at the press preview? In recent years Michael Heizer, whose mammoth desert project is being funded by Dia and Lannan, and who was a pal of Smithson in the latter's lifetime (he died in 1973), has whacked his dead friend in print (in the New York Times, 12/12/99) and claimed his own priority (saying, "High-speed hustler. . . . What was some guy from New Jersey doing building a sculpture like mine on a lake in Utah?").

For a sculptor, this is remarkably simplistic thinking. Both huge sculptures are made of earth and are of the same stylistic genre, but Smithson's Spiral Jetty, a flat earthen coil in a lake that dates to April 1970, is not at all "like" Heizer's Double Negative, a pair of 50-foot deep, 240,000-ton excavations in a mesa that dates to December 1969-June 1970. (The issue of Earthwork priority is taken up in my book, Earthworks: Art and the Landscape of the Sixties on pp. 236-237.) Also in that article, Heizer back-dated the origin of his desert City by two years, to 1970 (all other documents list 1972) and says that while he slaved in obscurity Smithson gained attention by publishing articles. Maybe so, but Smithson died in July 1973, before Heizer got very far into his 30-year opus.

The prominence at Dia: Beacon -- and in illustrations of articles about it -- of Heizer's grandiose enlargement in concrete of four geometric holes, first made in the snow in 1967, in contrast to the constricted presentation of Smithson, suggests that some who should know better are performing acts of ventriloquism for Heizer, sabotaging Smithson's standing.

Overall, what is impressive about Dia's Beacon endeavor, beyond awe for this facility (and shock at the kind of historical revisionism suggested above), is the idealism that underlies it. The display amounts to an admirable statement about the value of serious modernist art.

Some such notion may explain the works' appeal to Heiner Friedrich, the former German art dealer who was Dia's founding visionary in New York in 1974. Born in Berlin in 1938, surviving the war to open a gallery in Munich in 1963, Friedrich presented De Maria's "Land Art" show in 1968 (the first earth room) and his New York Earth Room at the close of his SoHo gallery in 1977.

Friedrich seems to have transferred what is a historic German attraction to landscape and the American West to an appreciation of New York's esthetic pioneers and their buckaroo bravado. Dia supported its chosen artists lavishly; its collection grew huge in numbers as well as in the works' scale. In 1977 Friedrich and Dia funded the construction of De Maria's Lightning Field in New Mexico and later bought a former fort in Texas for Judd.

The problem, though, is that conceptions of what serious, innovative art is changes through time. But instead of allowing ideas of "the way we were" in art to flow like a river, Dia has channeled it into a trough. Throughout changes in directors (Friedrich exited in 1985), the organization has maintained an affiliation with a certain '60s "generation," historically bracketed by Louise Bourgeois' sculptural psychodramas -- placed here, like a batty aunt, in a dank attic -- and Bruce Nauman's video antics, screaming in the murky basement.

Hanne Darboven, Blinky Palermo and Gerhard Richter are among the few Europeans. The one artist who appears truly current is Robert Irwin, who came on the scene in the '60s and who continues to respond to values even as they change. Many at the press preview enthused that Irwin's landscaping, including gridded tufts of grass and an alley of fruit trees along his angled parking slots, was the best work of art at the museum (the integration of nature into culture provides relief).

If Dia wants to collect only that golden age -- as several historians of the '60s have termed it -- then the organization's curators should recognize that the strategies for interpreting the '60s, and presenting the decade's art, have broadened considerably. All of its works were anti-Establishment, countering traditional culture (and the society that had gotten us into Vietnam), often with rough nature.

The political and social context of these works, then, needs to be more directly acknowledged. Memories are short, art history has been downsized (at least in curricula), and Dia is located on the periphery of a recently seedy mid-Hudson town anticipating economic revival. Thus, forgo this white box exclusivity for the adoption of the current practice of informative wall labels, photographic documentation of contemporaneous history, and educative brochures.

More adventurously, the Dia administration needs to do what every museum director (and corporate CEO) does: correct its institutional blindness to certain artists and infatuation with others. And it might consider reflecting the fact that the world is not as Caucasian and confident as it was in the 1960s. Continuing its program of an almost spiritualized abstraction, Dia could begin by looking at Martin Puryear and Anish Kapoor.

It would be great to be able to relive the glory of '60s optimism (as recent clothing styles tease us to do), and it is wonderful to see at Dia the creative fruition of that period. But since we can't go back, let's do what the '60s did: embrace new ways of thinking, about the past and the present.