Formalism as a theoretical position of Aesthetics and art criticism is distinctively 'modern' in that it is a theory developed to strongly defend modern art against the concept and value of art in Classicism, ie. the imitation theory. Under formalism, there is a belief of the autonomy of art, and this belief is what formalism and modern art have in common. Nevertheless, the extension of formalism is not the same as that of modern art, because in the course of its development, modern art came to include Avant-Garde which negate the autonomy of art under the phrase of 'anti-aesthetic.' Therefore, we can only say that formalism is related to a certain stream of modern art, and this stream is modernism which has pursued the autonomy of art in the visual area.
There are various positions in formalism as a theory to expand or defend modernism. It is generally regarded as a theory for the value of modernist art, but it can also be a theory for a definition of modernist art, for ontology of an artwork, or even for an art history. Categorical difference in formalism can be explicitly seen by the comparison of two famous 'formalist' art critics: Roger Fry and Clement Greenberg. Fry was concerned with the defense of the value of 'modern' painting, or purely visual image, which was totally different from the traditional picture, so for him, formalism means a theory related to the value of a modern work of art. However, Greenberg's concern was different from Fry's. He was interested in both the discernment of 'truly living' art from various sorts of phenomenon in modern art and the construction of the history of that 'truly living' art. With these two concerns, Greenberg's formalism becomes a unique theoretical complex. It is, first of all, a theory for the definition of art, and then it is a theory of art history.