Which is more musical, a truck passing by a factory or a truck passing by a music school?
John Cage, "Communication", the third of the Composition as a Process lectures given in Darmstadt in 1958 and published in Silence. Many of Cage's works use sounds traditionally regarded as unmusical (radios not tuned to any particular station, for instance): he really did believe that the sound of a truck and the sounds made in a factory had just as much musical worth as the sounds made in a music school. There is also a suggestion expressed in the quote that in order to determine the artistic worth of something, it is necessary to examine the context in which it exists.
A sound does not view itself as thought, as ought, as needing another sound for its elucidation, as etc.; it has not time for any consideration--it is occupied with the performance of its characteristics: before it has died away it must have made perfectly exact its frequency, its loudness, its length, its overtone structure, the precise morphology of these and of itself.
Whenever you wash dishes, cook, or clean, if you make no sound, this is smartness itself. A person who enters a house and makes a lot of noise is revealing a lack of spirituality; even cats and dogs do not make unnecessary sounds, and man as he naturally is does not make any either.
If a tree falls in a forest, and no-one is around to hear it, does it make a noise?
Source unknown, but apparently originating in the twentieth century; a 1910 physics book asks "When a tree falls in a lonely forest, and no animal is near by to hear it, does it make a sound? Why?" Charles Riborg Mann, George Ransom Twiss, Physics (1910), p. 235. See also: If a tree falls in a forest.