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• 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.
  • John Cage (1955), quoted in Classic Essays on Twentieth-Century Music, ISBN 0028645812

• Music has no subject beyond the combinations of notes we hear, for music speaks not only by means of sounds, it speaks nothing but sound.
  • Eduard Hanslick, quoted by Wolfgang Sandberger (1996) in the liner notes to the Juilliard String Quartet's Intimate Letters. Sony Classical SK 66840.

• You know the sound of two hands clapping; tell me, what is the sound of one hand?
  • Hakuin Ekaku (1686-1769). The phrase is a Kōan, an irrational comment used in Zen Buddhism in order to assist practitioners in reaching enlightenment.

• Could we not imagine that noise...is itself nothing more than the sum of a multitude of different sounds which are being heard simultaneously?
  • Jean-Jacques Rousseau, Dictionnaire de Musique (1767)

• 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.

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• Noise proves nothing. Often a hen who has merely laid an egg cackles as if she has laid an asteroid
  • Mark Twain