From
R. Murray Schafer, Ear Cleaning: Notes for an Experimental Music Course (1967)

“programs which force music out of the little bag into which educators put it many years ago. Today serious artists everywhere are seeking the precise points where the nerve-endings of each art stretch out to touch hose of the other arts. Distinctions which seek to keep the arts in separate categories are disintegrating and the contemporary art of both Europe and america is becoming increasingly synthetic. Thus we have stereophonic compositions, graphic poems and kinetic sculpture. In the past, critics have spoken of the ‘spatial’ as opposed to the ‘temporal’ arts. But recent developments in the arts have tended to dissolve these distinctions for, as Minkowski and Einstein discovered at the beginning of this century, neither space not time can preserve an independent existence; both exist simultaneously in an ever-present four dimensional continuum”.