Acoustic space is spherical. It is without bounds 
or vanishing points. It is structured by pitch 
separation and kinesthesia. It is not a container. 
It is not hollowed out. It is the space in which men 
live before the invention of writing—that 
translation of the acoustic into the visual. Pre-
literate man does not trust his eyes very much. 
The magic is in sound for him, with its powers to 
evoke the absent.

Marshall McLuhan to Wyndham Lewis, Dec. 18, 
1954, Letters of Marshall McLuhan , (Toronto, 
1987), p. 245.