How did Clement Greenberg define the importance of an artwork’s medium?

For the art critic Clement Greenberg, the importance of an artwork was defined by its commitment to its specific material medium. In his formalist approach, Greenberg argued that the most significant quality of a work was its "articulation of the medium"—specifically, the finessing of the terms inherent to the material, such as the flatness of a canvas in painting.12

Greenberg believed that for art to achieve "aesthetic unity," it had to be "purified" by eliminating elements that were beside the point, such as literary, anecdotal, or symbolic content. By focusing on these intrinsic qualities, he sought to create a purely aesthetic experience that rendered the work autonomous and self-sufficient.1

Ultimately, Greenberg viewed the history of modern art as a progressive march toward this pure abstraction, where the work acknowledges its own material nature—for instance, by emphasizing the flatness of the surface rather than attempting to represent three-dimensional space.12