Awelye (Ceremony), 1994 Emily Kam Kngwarray

There's a funny story about Rover Thomas and the American color-field abstractionist Mark Rothko. Thomas, a (late) aboriginal artist from the northwest of what's now called Australia—one of his earth-toned paintings is displayed in the exhibition Ancestral Modern at Seattle Art Museum—walked up to a Rothko, took one look, and said to his curator friend, "Who's that bugger who paints like me?"

There's no denying: The two artists' works look alike. But an object becomes art when it moves past the visual. Rothko was a tortured product of the Mad Men age, conjuring fields of color in a perpetual attempt to reach an apotheosis that would cut through the hollowing-out, commercializing forces—even as his paintings were already becoming commodities. He killed himself in 1970, and to this day, Rothkos are the modern artworks most likely to bring people to tears, the historian James Elkins has written. The lonely, individualistic despair of the paintings is palpable—the way you know how far to stand from a Rothko is by positioning yourself so that the painting fills your visual field, with no extra peripheral space. You are meant to look alone.

Where Rothko's visions are soft, placeless clouds, Thomas painted the specific hard earth of the Kimberly region. Swaths of red and yellow connote sandstone and dunes. Dotted lines recall gravel ridges. Thomas started as a painter after a cyclone hit his people's ancestral lands in 1974. The residents had been scattered by white assimilators, their ancient visual traditions remaining in the presence of 40,000-year-old rock art but dying out in the lives of contemporary indigenous people. The spirit of a relative who'd died in the storm came to Thomas with instructions to paint. He embarked on painting as a way to reunite his people, to reconnect them with the ancestors embedded in their lands, and to carry forward the oldest known tradition of artmaking on the planet. He inspired other aboriginal painters in the Kimberly. Aboriginal paintings like Thomas's—maps of lands that aboriginal people know better than anyone else—have been used in Australian courts as proof of land ownership, as legal documents. A Rothko is many things, but it is not a legal document. Aboriginal art is not abstract art. It also does not appear to have time for despair. Protest, sometimes, yes. But no wallowing.

Ancestral Modern includes 120 paintings and sculptures, and all will be coming into SAM's collection thanks to the collectors Margaret Levi and Robert Kaplan. Seattle is now the place to go for contemporary Australian aboriginal art in the United States. The link is arbitrary—Levi and Kaplan happen to live and work here, happen to love this art—but there is a profound connection to be made: Seattle is a city of people whose identities are tied to the land. Cities are not typically about land, but this one is. The mountains and waters are the views and the weekend escapes, echoed during the week by trips up and down the central city's steep hills. Many of Seattle's artists are preoccupied with tracking, mapping, and building unconventional landscapes. An aboriginal spirit flows under everything. A delegation from the local Salish tribes provided the welcome for Ancestral Modern artists and curators last week, not Seattle's mayor or city council. The ceremony involved gifts and music, and was entirely private.

The "secret-sacred" aspect of indigenous art is important. Its layers are only understood according to your relationship to it. An outside viewer may see a shimmering field of tight cross-hatching and herringbone, quickly learn what the pattern is called (rarrk—grreat name), its inspiration (the painting of land forms directly onto bodies for rituals), and that the artist wants to achieve a vibrational effect signaling the presence of sacred ancestors. But there are more layers. Some are known only to aboriginal women, some to men, some to certain types of initiates. The artworks are cosmological. How you read them depends on what role you play. They don't just show something to the viewer, they position the viewer. In the case of the works in Ancestral Modern, even the most outsider role is pretty incredibly satisfying.

The exhibition is laid out geographically as the sun rises and sets: You begin with artists from the east and move west. There are desert rooms and water rooms. The paintings date back to the 1960s, when aboriginal people first began to use art to fight publicly for the survival of their culture. Many are meditative, like Gunybi Ganambarr's sparkling and lacy diamond shapes incised into bark and representing fresh water. A few record historical horrors, like Queenie McKenzie's symbolic depiction of the massacre of Gija people by ranchers, a hill shape stained at its base with the blood of babies thrown against it.

The most recent piece in the exhibition is a funerary installation shaped like a boat and made out of sand, on the floor in the center of the entrance gallery. It was created the day before the exhibition's opening by Jamie Wunungmurra and Ishmael Marika, whose grandparents' artworks are also at SAM. Thrust upright into the boat of sand are hollow-log coffins, their surfaces intricately painted. These are art versions of the objects that would be planted into the ground and left out for the elements in the Blue Mud Bay region on the eastern coast of Arnhem Land. The logs would contain the bones of the deceased, whose spirits will become ancestral after this second burial. (A first burial is followed by a period of grieving and not uttering the person's name.) On the wall next to the installation is a video with idyllic scenes of dancing and music, shot by Marika in Blue Mud Bay. The young artists, wearing baseball caps and T-shirts, said the exhibition is "nice, but we're homesick."

In the next rooms is a buzzing, glorious world. Imagine if Tibetan mandalas met the night sky met Keith Haring met Agnes Martin met Vincent van Gogh met a rainbow met feminist body art met a fire met a spider met a banquet table set for a feast, and you could look at everything from a satellite view and through a microscope, back and forth.

Immediately sweeping into view are the dazzling visions of a rash of female painters: galaxies of dots by Kathleen Petyarr; quivering lines by Doreen Reid Nakamarra; Eileen Napaltjarri's blaze; Abie Loy Kamerre's ecstatic horizon, striped like a vinyl record using the colors of the best song imaginable. Of Emily Kam Kngwarray's bursting tangle of red, purple, and peach tendrils, cocurator Pam McClusky asks, "How many of you have ever seen a great painting devoted to tubers?" It's a portrait of yams under the ground. Kngwarray's canvases of color swiped in downward rows are based on, and feel like, living painted bodies.

There are those who say that aboriginal art is necessarily political, and, while you don't have to carry this into the galleries, politics are intrinsic to Ancestral Modern. The original force behind the collection, Margaret Levi, is a political economist at the University of Washington who works with the World Bank to support ethical supply chains. Levi and Kaplan avoid dealers who exploit artists, often buying from cooperatives that split sales between the artist and the whole tribe.

Ancestral Modern does not and cannot provide a portrait—when white people turned up 200 years ago, there were already 600 languages and dialects spoken on the continent. But a worldview does emerge. In old black-and-white video footage playing in one gallery, a chorus of aboriginal students wearing face paint is led by a white teacher in "This Land Is Your Land." It's a weird moment. If Ancestral Modern teaches anything, it's that nobody owns land, just some people know it better than others. recommended