human experience of different humans. Arrival of Modernism The arrival of Modernism in the late 19th century lead to a radical break in the conception of the function of art, and then again in the late 20th century with the advent of postmodernism. Clement Greenberg's 1960 article "Modernist Painting" defines modern art as "the use of characteristic methods of a discipline to criticize the discipline itself". Greenberg originally applied this idea to the Abstract Expressionist movement and used it as a way to understand and justify flat (non-illusionistic) abstract painting: Realistic, naturalistic art had dissembled the medium, using art to conceal art; modernism used art to call attention to art. The limitations that constitute the medium of painting—the flat surface, the shape of the support, the properties of the pigment—were treated by the Old Masters as negative factors that could be acknowledged only implicitly or indirectly. Under Modernism these same limitations came to be regarded as positive factors, and were acknowledged openly. After Greenberg, several important art theorists emerged, such as Michael Fried, T. J. Clark, Rosalind Krauss, Linda Nochlin and Griselda Pollock among others. Though only originally intended as a way of understanding a specific set of artists, Greenberg's definition of modern art is important to many of the ideas of art within the various art movements of the 20th century and early 21st century. Pop artists like Andy Warhol became both noteworthy and influential through work including and possibly critiquing popular culture, as well as the art world. Artists of the 1980s, 1990s, and 2000s expanded this technique of self-criticism beyond high art to all cultural image-making, including fashion images, comics, billboards and pornography. Duchamp once proposed that art is any activity of any kind-everything. However, the way that only certain activities are classified today as art is a social construction. There is evidence that there may be an element of truth to this. In The Invention of Art: A Cultural History, Larry Shiner examines the construction of the modern system of the arts, i.e. fine art. He finds evidence that the older system of the arts before our modern system (fine art) held art to be any skilled human activity; for example, Ancient Greek society did not possess the term art, but techne. Techne can be understood neither as art or craft, the reason being that the distinctions of art and craft are historical products that came