Our laws of media  are observations of the 
operation and effects of human artefacts on man 
and society, since a human artefact “is not merely 
an implement of working upon something, but an 
extension of our body, effected by the artificial 
addition of organs; . . . to which, to a greater or 
lesser degree, we owe our civilization.”

Marshall McLuhan and Eric McLuhan, Laws of  
Media: The New Science , (Toronto, 1988), p. 94.