Media ecology argues that media act as extensions of the human senses in each era, and communication technology is the primary cause of social change. McLuhan is famous for coining the phrase, "the medium is the message", which is an often-debated phrase believed to mean that the medium chosen to relay a message is just as important (if not more so) than the message itself. McLuhan proposed that media influence the progression of society, and that significant periods of time and growth can be categorized by the rise of a specific technology during that period.