Adorno, Aesthetic Theory (1970), translated by Robert Hullot-Kentor:
Posed from on high, the question whether something such as film is or is no longer art leads nowhere. Because art is what it has become, its concept refers to what it does not contain. The tension between what motivates art and art’s past circumscribes the so-called questions of aes thetic constitution. Art can be understood only by its laws of movement, not ac cording to any set of invariants. It is defined by its relation to what it is not. The specifically artistic in art must be derived concretely from its other; that alone would fulfill the demands of a materialistic-dialectical aesthetics. Art acquires its specificity by separating itself from what it developed out of; its law of movement is its law of form. It exists only in relation to its other; it is the process that tran spires with its other. Nietzsche’s late insight, honed in opposition to traditional philosophy, that even what has become can be true, is axiomatic for a reoriented aesthetic. The traditional view, which he demolished, is to be turned on its head: Truth exists exclusively as that which has become.