At the turn of the century a group of colorful French artists banded together in order to get the jump on the bourgeois notion of progress. This bohemian brand of progress gradually developed into what is sometimes called the avant-garde. Both these notions of duration are no longer absolute modes of "time" for artists. The avant-garde, like progress, is based on an ideological consciousness of time. Time as ideology has produced many uncertain "art histories" with the help of mass-media. Art histories may be measured in time by books (years), by magazines (months), by newspapers (weeks and days), by radio and TV (days and hours). And at the gallery proper – instants! Time is brought to a condition that breaks down into "abstract-objects". The isolated time of the avant-garde has produced its own unavailable history or entropy.

Robert Smithson, 'Quasi-Infinities and the Waning of Space' in The Writings of Robert Smithson, (New York University Press, 1979) p. 35