I imagine that as contemporary music goes on changing in the way that I'm changing it what will be done is to more and more completely liberate sounds from abstract ideas about them and more and more exactly to let them be physically uniquely themselves. This means for me: knowing more and more not what I think a sound is but what it actually is in all of its acoustical details and then letting this sound exist, itself, changing in a changing sonorous environment.

1952, quoted in Classic Essays on Twentieth-Century Music, ISBN 0028645812