extension
All media are extensions of some human faculty - psychic or psysical. The wheel is an extension of the foot, the book is an extension of the eye… clothing, an extension of the skin… electric circuitry, an extension of the central nervous system. Media, by altering the environnement, evoke in us unique ratios of sense perceptions. The extensin of any one sense alters the way we think and act - the way we perceive the world. When these ratios change, men change.
Marshall McLuhan, Quentin Fiore, The medium is the massage, A penguin book, 1967, pp. 26-41.
