to the light bulb as an example. A light bulb does not have content in the way that a newspaper has articles or a television has programs, yet it is a medium that has a social effect; that is, a light bulb enables people to create spaces during nighttime that would otherwise be enveloped by darkness. He describes the light bulb as a medium without any content. McLuhan states that "a light bulb creates an environment by its mere presence".

More controversially, he postulated that content had little effect