… Duchamp handed on the freedom to the audience, and with it uncertainty.
This is from ‘Picasso and Duchamp’ (1989) in About Modern Art: Critical Essays 1948-96 by David Sylvester (1996):
… Picasso’s desire that we do recognize the source of the fragments of reality which he absorbed and transformed suggests that he would have felt the same about the existing art which he absorbed and transformed — that we should be conscious of the prototype and thus of the extravagance of the adaptation. It is like a composer writing a set of variations on an existing tune: if we don’t identify the original, part of the meaning is lost. Nothing was more central to Picasso’s art than his obsession with metamorphosis, and the efficacy of a metamorphosis depends absolutely on our knowing what the thing was before it was changed.
… The time when Picasso was making his first junk sculptures was also the time when Duchamp made his first sculpture from ready-made materials. It was a bicycle wheel placed upside down on a stool. … The stool and the wheel are the origins of civilization, and Duchamp rendered them both useless. Picasso took junk and turned it into useful objects such as musical instruments; Duchamp took a useful stool and a useful wheel and made them useless.
… Duchamp renders the bicycle wheel and the stool useless, but neither more nor less useless than art is. He turns them into things that are there only to be looked at. Where Picasso seems to be saying that bicycle parts can become sculpture through the force of his personal magic, Duchamp seems to be saying that bicycle parts can become sculpture simply by being treated as sculpture.
[ … ]
… Since the onset of the Romantic movement, artists have made a demand for total freedom. In our time freedom has come to be demanded of the artist by his public. The artist’s position has become that of someone to whom we say: ‘Stand up over there and make a five-minute speech about anything you like and if I’m amused I’ll give you a present.’ This approach, at once over-indulgent and uninvolved, has been an encouragement to the artist to develop an attitude of not taking responsiblity for how he is read.
[line bread added] It was an attitude totally repugnant to Picasso, who is quoted by Françoise Gilot as saying to Matisse while looking at some Pollock reproductions that it was all very well for Valéry to affirm that he wrote half a poem while the reader wrote the other half, but that he for his part did not want there to be three or four or a thousand possibilities of interpreting a work of his; he wanted there to be one.
Given the modern artist’s freedom, Picasso gloried in the possibilities it opened for unconfined and unambiguous self-revelation; Duchamp handed on the freedom to the audience, and with it uncertainty. The Dionysian and the Apollonian.