As he abandoned painting for sculpture in the early 1960s, he wrote the essay “Specific Objects” in 1964. In his essay, Judd found a starting point for a new territory for American art, and a simultaneous rejection of residual inherited European artistic values, these values being illusion and represented space, as opposed to real space. He pointed to evidence of this development in the works of an array of artists active in New York at the time, including H.C. Westermann, Lucas Samaras, John Chamberlain, Jasper Johns, Dan Flavin, George Earl Ortman and Lee Bontecou. The works that Judd had fabricated inhabited a space not then comfortably classifiable as either painting or sculpture and in fact he refused to call them sculpture, pointing out that they were not sculpted but made by small fabricators using industrial processes. That the categorical identity of such objects was itself in question, and that they avoided easy association with well-worn and over-familiar conventions, was a part of their value for Judd. He displayed two pieces in the seminal 1966 exhibit, "Primary Structures" at the Jewish Museum in New York where, during a panel discussion of the work, he challenged Mark di Suvero's assertion that real artists make their own art. He replied that methods should not matter as long as the results create art; a groundbreaking concept in the accepted creation process. In 1968, the Whitney Museum of American Art staged a retrospective of his work which included none of his early paintings.