In this Marxist-influenced essay, Greenberg claimed that true avant-garde art is a product of the Enlightenment's revolution of critical thinking, and as such resists and recoils from the degradation of culture in both mainstream capitalist and communist society, while acknowledging the paradox that, at the same time, the artist, dependent on the market or the state, remains inexorably attached "by an umbilical cord of gold".

Greenberg writes: Kitsch, using for raw material the debased and academicized simulacra of genuine culture, welcomes and cultivates this insensibility.

[4]For Greenberg, avant-garde art was too "innocent" to be effectively used as propaganda or bent to a cause, while kitsch was ideal for stirring up false sentiment.

In the years after World War II, Greenberg pushed the position that the best avant-garde artists were emerging in America rather than Europe.

In the 1955 essay "American-Type Painting", Greenberg promoted the work of Abstract Expressionists, among them Pollock, Willem de Kooning, Hans Hofmann, Barnett Newman, and Clyfford Still, as the next stage in Modernist art, arguing that these painters were moving toward greater emphasis on the "flatness" of the picture plane.

He praised similar movements abroad and, after the success of the Painters Eleven exhibition in 1956 with the American Abstract Artists at New York's Riverside Gallery, he traveled to Toronto in 1957 to see the group's work.

On the one hand he maintained that pop art partook of a trend toward "openness and clarity as against the turgidities of second generation Abstract Expressionism."

[7] During the 1960s, Greenberg remained an influential figure on a younger generation of critics, including Michael Fried and Rosalind E. Krauss.

[8] In his book The Painted Word, Tom Wolfe criticized Greenberg along with Harold Rosenberg and Leo Steinberg, whom he dubbed the kings of "Cultureburg".

He suggested this process attained a level of "purity" (a word he only used within scare quotes) that revealed the truthfulness of the canvas, and the two-dimensional aspects of the space (flatness).

PAM exhibits the works primarily in the Jubitz Center for Modern and Contemporary Art; some sculpture resides outdoors.

Artists represented in the collection include Edward Avedisian, Walter Darby Bannard, Stanley Boxer, Jack Bush, Anthony Caro, Dan Christensen, Ronald Davis, Richard Diebenkorn, Enrico Donati, Friedel Dzubas, André Fauteux, Paul Feeley, Helen Frankenthaler, Robert Goodnough, Adolph Gottlieb, Hans Hofmann, Wolfgang Hollegha, Robert Jacobsen, Paul Jenkins, Seymour Lipton, Georges Mathieu, Kenneth Noland, Jules Olitski, William Perehudoff, Jackson Pollock, Larry Poons, William Ronald, Anne Ryan, David Smith, Theodoros Stamos, Anne Truitt, Alfred Wallis, and Larry Zox.