The electric media are a physical extension of our 
own organic nervous system, which is literally 
constituted by electric impulses. When you put an 
electric system, or field, around you, you enlarge 
your own nervous system. Just as the wheel 
extends your foot, the “wired planet” now extends 
our nerves. All technology is a physical extension 
of man, and our bodies, said Emerson, are a 
“magazine” or storehouse of all past, present, 
and future innovations.

Marshall McLuhan,“Technology and the Human 
Dimension,” Marshall McLuhan: The Man and His  
Message , (Golden, 1989), p.12.