Clement Greenberg and Harold Rosenberg were the critical rivals of their times. With action, event, and the moment of creation at the center of importance, Rosenberg's stand found no place in the land of Greenberg's formality and rationalism. One man had found value in the psychological, while the other found it in the retrospective. However, despite having diametrically different views, Greenberg and Rosenberg supported the movement of Abstract Expressionism with equal vigor.
Rosenberg's view of what a canvas actually represented was described as “an arena in which to act.” He thought of it as a space for an artist to create an “event” instead of an image, which was the result of an “encounter” with the artist and his medium. These concepts were the basis of Rosenberg’s most famous and timeless notion, that which he called “Action Painting”, which would later be described as Abstract Impressionism. It was the avant-garde work of artists that abandoned the object oriented goals of painting and painted “just to paint”, and not to make anything else but a painting, in it's most basic essence. For Rosenberg, these works of art revolved around expression of the inner man, and were thus purely self creation. These ideas of the artists perspective being looked through to criticize art was much more than a stones throw away from the narrow and intolerant path of Greenberg’s criteria. Rosenberg was an existentialist. He believed that, when represented in a piece, the human condition lent the most value to a work of art. This preference lead him to favor the works of artists like Willem de Kooning, with pieces like“Woman and Bicycle”, for example.

Greenberg placed heavy value on abstraction as the vital ingredient to a modern painting. For a work to be an authentic modern piece, each medium used would need to distinguish itself from other, related mediums. He viewed this