This excerpt is from "On the Manner of Addressing Clouds" by Thomas McEvilley.

In the section of the article entitled "Thirteen Ways of Looking at a Blackbird" McEvilley discusses thirteen ways in which content is created in art.
One way is through the materials of which the art is made.

"Content arising from the material of which the artwork is made.

Within the category of sculpture in the 1960's and 70's, an artist working marble representationallly was at one level making a statement opposed to that of the artist working with industrial I- beams or fire. Traditional art materials, industrial materials, esoteric high-tech materials, absurdist materials (like Ed Ruscha's chocolate), neoprimitive materials (like Eric Orr's bone and blood), pantheistic materials (Klein's fire, and so on), deceptive self-disguising materials (plastic that looks like plaster, wood prepared to look like stone) - all these decisions by the artist carry content quite as much as form. They are judgment pronouncements that the art viewer picks up automatically without necessarily even thinking of them as content. They are statements of affiliation to or alienation from certain areas of cultural tradition, as, say, the use of industrial I-beams represents a celebration, or at least an acceptance, of urban industrial culture, the use of marble or ceramic suggests nostalgia for the pre-Industrial Revolution world."