The Earthworks Alloway had been writing about by Smithson, Heizer, and Oppenheim were monumental and “it is only on this basis that the core works of the movement can be understood.” Cities often sought monumental, public artworks, but he realized that Earthworks “would not work in cities… there is just too much interference from a lively and complex environment.” However, the activities of artists beyond galleries had kindled what Alloway referred to as an “unprecedented interest in public art” in the mid-1970s. Unlike any other of his writing, Alloway approached public art not in terms of a descriptive aesthetic, but through a set of principles. A way of understanding these principles was his 1974 critique of Barbara Hepworth's Single Form sculpture in the grounds of the United Nations in New York. There was no significant distinction between Hepworth's sculptures for a gallery or outdoor setting, and this was the problem: “Modern sculpture does not become public merely by being set out of doors.” Two changes occurred when art comes out of the gallery. First, the scale of its environment changes. What can be perceived as a large sculpture in a gallery can look insignificant or dwarfed in a public space. Second, a publicly sited work should have “a capacity to symbolize a public theme.” In the case of Hepworth's sculpture, Alloway thought it was “a failure as a public work, which is not the same thing as saying it is a bad Hepworth.” He argues for appropriateness: “Formal statements are highly satisfactory in a social context that is compatible with them (like a gallery), but displaced to the crowded and intricate communication system of the city they are fragile.” As a public mode, abstraction had “no effective way to communicate with people at random,” and so what the sculpture signifies is little more than “the presence of the artist: it is a Barbara Hepworth and that is the end of it.” It could be described as a “failure of sociability” in Modernist art. As such, the failure of public art is “not so much the result of the brute public but of dumb artists.”

Alloway's first principle, as he outlined it in 1972 in Studio International, was that iconography—and this time Alloway used the term iconography conventionally—had to be addressed.