One of the most famous works of art in America, Robert Smithson’s Spiral Jetty transcends the “earth art” genre to which critics have consigned it, and has become an emblem of the American sublime. It is made of black basalt boulders, bulldozed into a straight line that stretches, jetty-like, 1,500 feet from the eastern shore in the upper reaches of the Great Salt Lake, terminating in a spiral with three whorls. From the air it has the look of a bishop’s crosier with an unusually ornamental crook. It has a way of disappearing and reappearing, which somehow gives it a touch of magic. Soon after it was made, it was submerged beneath the saline water that gives the lake its name, and on re-emerging at a later time, when the water-level fell, it was covered with a dense patina of salt crystals. It is reached with difficulty, requiring a trek over rutted roads, and there is no guarantee that it will be visible when one gets there; I failed to see it on the two occasions I made the attempt. So the work is as elusive as it is compelling, and though it belongs to its moment in history, it also has the timeless air of some ancient monument left behind by a vanished civilization.

Smithson’s intentions remain difficult to discern. He appears to have been interested in Great Salt Lake at first because he’d been told that the water was the color of tomato soup. “That was enough of a reason to go out there and have a look,” he writes. Recalling his first visit, he wrote as if the site itself implied the work:

As I looked at the site, it reverberated out to the horizons only to suggest an immobile cyclone while flickering light made the entire landscape appear to quake. A dormant earthquake spread into the fluttering stillness, into a spinning sensation without movement. The site was a rotary that enclosed itself in an immense roundness. From that gyrating space emerged the possibility of the Spiral Jetty. No ideas, no concepts, no systems, no structures, no abstractions could hold themselves together in the actuality of that evidence.

Reading these lines, one has the impression that Smithson is resorting to a kind of logical stammering–“immobile cyclone,” “dormant earthquake,” “fluttering stillness”–to convey a reality that transcends the limits of rational thought. And the work he made from this site has a similar effect on critics, whom it ultimately leaves speechless, as befits the sublime. Spiral Jetty fits Kant’s notion of meaningfulness without any specific meaning. Its closest artistic kin in North America is the great Serpent Mound outside Cincinnati, about which nothing is really understood.

Still, like everything else he did, Spiral Jetty had a polemical subtext. Smithson writes:

Logical purity suddenly finds itself in a bog, and welcomes the unexpected event…. In the Spiral Jetty the surd takes over and leads one into a world that cannot be expressed by number or rationality. Ambiguities are admitted rather than rejected, contradictions are increased rather than decreased–the alogos undermines the logos. Purity is put in jeopardy.

In 1970, when Smithson made Spiral Jetty, these were fighting words. For purity had been a defining criterion for New York artists and art critics in the orbit of Clement Greenberg. In his 1960 paper “Modernist Painting,” Greenberg argued that aesthetic purity required the elimination from any art of whatever does not belong to the medium that defines it. Painting, for example, had to become flat and abandon figuration, which suggested a relationship to the three-dimensional reality beyond it, while sculpture had to reject any painterly qualities. “Thus would each art be rendered ‘pure,’ and in its ‘purity’ find the guarantee of its standard of quality.” But purity seemed entirely beside the point of Spiral Jetty. Hence the wry joke contained in Mark Tansey’s 1982 painting Purity Test. Painted in his characteristically uninflected illustrational style, Tansey’s work shows a group of four American Indians depicted in the late-nineteenth-century style of Frederick Remington, mounted on horses, gazing downward from a rise in the land onto Spiral Jetty extending into the lake below them.

Comically impossible though such an encounter is, it raises an interesting question: Presumably innocent of the history of art, and certainly of the art history of the future, what would Remington’s Indians have made of Smithson’s work? Would they have regarded it as a celebration of, as it were, the rockiness of rocks–would Spiral Jetty have passed their purity test, if they had one? From their look of awe, it would seem that the work is fraught with meaning of a deeper kind, as it is for us, and as it was for Smithson himself. Whatever he may have set out to make, Spiral Jetty rose above its critical context. The truth is, we probably know as little about how to interpret it as Tansey’s Utes would have.

Though he studied painting at the Art Students League, Smithson found his calling as a sculptor in the 1960s, when that medium was undergoing an immense transformation. He was included in the exhibition “Primary Structures,” which took place in April 1966 at the Jewish Museum on upper Fifth Avenue. Curated by Kynaston McShine, the show gave the larger art world its first real glimpse of what was happening in sculpture as it began to replace painting as the defining medium of artistic experiment.

The paradigmatic “primary structure”–the term was controversial at the time–was drab, monolithic, industrial, repetitive, empty and monumental. Smithson showed a set of six “cryomorphic” hexagons, arrayed in a single row, based on the geometry of ice crystals. That year he published a stunning essay in Artforum, “Entropy and the New Monuments,” which connected the Second Law of Thermodynamics with “primary structures,” explaining the latter’s Minimalist aesthetics in terms of civilization running down.

An autodidact, widely read in science fiction, amateur geology and crystallography, Smithson was a singularly original thinker who brought to bear in his art and writing as many of his intellectual pursuits as he could. His master concept was entropy–a statistical measure of energy disorder or randomness–which gripped him much as the concept of blind will gripped Arthur Schopenhauer, as the ultimate reality against which form and order crumple and collapse. He connected the coolness of contemporary sculpture with the inevitable cooling down of physical systems. Thus, he suggested, the most important new works in American sculpture “bring to mind the Ice Age rather than the Golden Age”–an allusion that suddenly vests his abstract ice crystals with a certain prophetic meaning. The new sculptors, in Smithson’s view, “provided a visible analog for the Second Law of Thermodynamics, which extrapolates the range of entropy by telling us energy is more easily lost than obtained, and that in the ultimate future the whole universe will burn out and be transformed into an all-encompassing sameness.” The “cold glass boxes” of contemporary architecture have “helped to foster the entropic mood…free from the general claims of ‘purity and idealism.'” We are left with “the flat surface, the banal, the empty, the cool, bland after blank; in other words, that infinitesimal condition known as entropy.” One is reminded here of Warhol’s aesthetics of boredom, as exemplified in his marathon films in which nothing happens.

It is difficult to imagine any art magazine–any magazine at all today–printing an essay like this, or like Smithson’s marvelous “A Tour of the Monuments of Passaic, New Jersey,” which appeared in Artforum the following year. In the essay he explores, like a travel writer, the monumental ruins of Passaic–six large pipes out of which water gushed like “liquid smoke,” parking lots, rusting machinery and “the houses mirror[ing] themselves into colorlessness.” And he asks with delicious irony, “Has Passaic replaced Rome as the Eternal City?” Passaic is eternal in the sense that it is Everywhereville. All cities are on the downward entropic path of the center city parking lot. “Primary Structures,” in his view, captured the direction of contemporary life to perfection.

Smithson’s conception of contemporary sculpture was striking, but it’s not clear the sculptors in question would have recognized their work in it. Many of these artists–Carl André, Donald Judd, Robert Morris, Dan Flavin–went on to become Minimalists, and their philosophy of art was far closer to Greenberg’s than to his. Their work often stressed purity of form and belonged to the museum, an institution about which Smithson had the deepest reservations. “Visiting a museum is a matter of going from void to void,” he wrote in 1967. “Hallways lead the viewer to things once called ‘pictures’ and ‘statues.’… Painting, sculpture, and architecture are finished, but the art habit continues. Art settles into a stupendous inertia.”

How to break this inertia? In a dialogue held later that year with Allan Kaprow titled “What Is a Museum?” Kaprow suggested an answer to Smithson: “You mentioned building your own monument, up in Alaska, perhaps, or Canada. The more remote it would be, the more inaccessible, perhaps the more satisfactory. Is that true?” Smithson replied: “I think ultimately it would be disappointing for everybody, including myself.” Still, there can be little question, judging from the ecstatic language of his writing about Spiral Jetty, that in Great Salt Lake he found something more primordial than primary structures, something more rawly connected to the energies of nature.

The museum world of 2005, alas, is no better prepared than it would have been in the 1970s to find an exhibitional format commensurate with Smithson’s stature and adequate to his achievement, although he is recognized as one of the most important artists of his time. After all, Smithson’s mature work was never intended to be shown in a museum, and indeed much of it is impossible to be shown there except in the form of documentation. What is described as the “first comprehensive American retrospective of Robert Smithson’s complex and highly influential body of work,” on view at the Whitney Museum of American Art until October 23, is inevitably a fairly entropic aggregation of sculptures in the “primary structures” mode; of juvenilia; of projects sketched out on graph paper, with cryptic notations like pirate maps; of documentary photographs and films of what I will designate his “unmuseumable” works; and examples of what Smithson called “non-sites”–sculptures that sought to overcome the distinction between indoors and outdoors, by bringing what Smithson calls the “focal point” of a site indoors. This meant bringing indoors a group of stones, or some seashells, or even what looks like gravel, and regimenting it by means of shaped containers in various configurations. Often the containers make use of mirrors, so that we see the shells or whatever reflected, giving the viewer some sense of the site from which they have been abstracted. Sometimes the non-site has the look of a gravel pile regularly punctuated with mirrors.

The film Smithson made of Spiral Jetty, projected in one of the galleries, is well worth watching. A critic once wrote that Spiral Jetty was the film, as if the truckloads of boulders were pushed into Great Salt Lake for the sake of being filmed. But films are easy to see. It is, I think, built into Smithson’s concept that his monument should be difficult to access–that it would require something of an ordeal to reach Rozel Point and look out over the salt-clad boulders, like the Indians in Mark Tansey’s painting.

The show’s catalogue makes few concessions to readers unfamiliar with the extensive art-historical literature devoted to the artist. The papers are by members of the A-list of Smithson specialists, writing chiefly if not exclusively for one another. I have no objections to such publications, which are contributions to scholarship of a kind the museum has a duty to support. But they leave the ordinary visitor high and dry. Visitors wander among the non-sites, peer at the drawings, point out doodled spirals to one another, puzzle over the maps, sit on benches in darkened galleries to see the films and wonder what anything has to do with anything else. In my view, Spiral Jetty was the breakthrough work in the epic that was Smithson’s journey as an artist. That is why his writing about it is so ecstatic. Everything before it was a kind of search.

The Whitney show succeeds, I think, in projecting a portrait of the artist as a restless demiurge whose basic genre was the monument, though none of his monuments can fit the space at the disposal of curators. The museum ought to be saluted for celebrating a figure who sought to invalidate the premises on which the idea of that institution rests. I would add that Smithson has become the beau idéal of young artists, more than Picasso, more than Duchamp the kind of figure they aspire to be–anti-institutional, in touch with the environment, hospitable to myth and ritual, alive to the poetry of the wilderness, ambitious in his desire to touch the public through a vision of monumentality that throws the world of the shopping mall and the parking lot into a moral perspective. In that respect the show tells us something about where we are. Spiral Jetty is a critique of modern life as entropy. The rest belongs to the scholars.