Conceptual Art, which emerged in the late 1960s, holds that the concept or idea behind the work is more important — or constitutes — the artwork itself. Its intellectual foundations lie in Marcel Duchamp's readymades, which proposed that art was a matter of selection and designation rather than making. Sol LeWitt's 1967 essay 'Paragraphs on Conceptual Art' argued that 'all the planning and decisions are made beforehand and the execution is a perfunctory affair.' Joseph Kosuth's One and Three Chairs (1965) — displaying a chair, a photograph of it and a dictionary definition — questioned the relationship between object, image and language. Conceptual Art dismantled assumptions about what art was, who made it, where it existed. It generated Installation Art, Performance Art, and much of what became contemporary art in the 1980s and beyond.