Eco on Media
This is from an essay by Umberto Eco, titled Towards a Semiological Guerrilla Warfare and published as part of his essay collection Travels in Hyperreality, where he refutes what Marshall McLuhan said about light as a medium:
To say that light is a medium is a refusal to realize that there are at least three definitions of light. Light can be a Signal of information (I use electricity to transmit impulses that, in Morese code, mean particular messages); light can be a Message (if my girlfriend puts a light in the window, it means her husband has gone out); and light can be a Channel (if I have the light on in my room I can read the message-book). In each of these cases the impact of a phenomenon on the social body varies according to the role it plays in the communication chain.
(I’m reading a Swedish translation, but thanks to Amazon’s new search feature, I could search for the passage and copy the above quote.)