Let us now survey briefly some of the more famous extant aesthetic theories in order to see if they do incorporate correct and adequate statements about the nature of art. In each of these there is the assumption that it is the true enumeration of the defining properties of art, with the implication that previous theories have stressed wrong definitions. Thus, to begin with, consider a famous version of Formalist theory, that propounded by Bell and Fry. It is true that they speak mostly of painting in their writings but both assert that what they find in that art can be generalized for what is "art" in the others as well. The essence of painting, they maintain, are the plastic elements in relation. Its defining property is significant form, i.e., certain combinations of lines, colors, shapes, volumes—everything on the canvas except the representational elements—which evoke a unique response to such combinations. Painting is definable as plastic organization. The nature of art, what it really is, so their theory goes, is a unique combination of certain elements (the specifiable plastic ones) in their relations. Anything which is art is an instance of significant form; and anything which is not art has no such form.