In 1964 the two artists who exemplified Alloway's thinking about “evidence” were Alexander Liberman (1912–1999) and Paul Feeley (1910–1966). Alloway interviewed Liberman for the catalogue of his April 1964 exhibition at Bennington, and discussed his work in Art International in the same month. In 1943 Liberman had been appointed Art Editor of Vogue, and he remained with Condé Nast publications for nearly half a century. Throughout the 1950s he painted a number of Minimal, Constructivist-influenced, symmetrical paintings whose purity and austerity was underlined by the employment of enamel paints on aluminium panels. Although contrasting starkly with Abstract Expressionist aesthetics, Liberman believed that art “should be an object of meditation” and so used primary shapes to communicate an “inner image structure” that would enable a “semi-telepathic communication between the creative artist and the spectator…” Upholding the Modernist ideals of Moholy-Nagy, he composed a picture and gave instructions for its making over the telephone; on others he pasted instructions on the reverse for how they could be mass-produced. Liberman learned to weld in 1959 and created metal sculptures from abandoned machinery that emphasized the material's rusty patina. In the early 1960s his painting became more mainstream in its Hard Edge style, although some of the paintings were, unusually, symmetrical. At the same time he created a group of polished aluminium sculptures with a Hard Edge/Constructivist aesthetic. Liberman met Alloway in 1961 and, soon after, asked him to write the short catalogue introduction to his highly successful exhibition at Betty Parsons's gallery in early 1962. Alloway was full of praise for Liberman's “brilliant symmetrical paintings” that enabled him to pursue his “concern for art as an idea, rather than as the issue of a highly physical creative procedure.” He was particularly impressed by the fact that the works were “encodable and repeatable” and so did not rely on uniqueness or idiosyncrasy. Their conceptual basis did not, however, mean they were visually impoverished—Alloway adjudged that their symmetry and uncompromising austerity “culminates in a forceful and heraldic figure…”

When Alloway came to write his piece for the 1964 exhibition and the Art International review, he had to deal with the fact that Liberman had changed his style radically, in 1962, on discovering Liquitex and the squeegee, and was now making far freer, gestural paintings—the reverse of Hard Edge.