Foster's talk about intermedia

In Foster’s article, Foster first introduced the concept of intermedia. However, I tried hard to distinguish the definition of “intermedia” and “multimedia” but still got confused.  Here is what I guess: Multimedia is some forms of media combine to represent something, while Intermedia is a form of medium that brings out meanings immediately.

Foster also talked about Duchamp’s “Fountain” in his article. To me, a glance at Duchamp’s work “fountain” can’t make me perceive meanings in it. At least, as a normal person, I can’t feel the relation between the mechanism and art in it. It no wonder brings great controversy and criticism after it is first showed on the exhibition. Probably what an art piece means can be no meanings at all. For example, in Duchamp’s another artwork, “bicycle”, it seems more random that Duchamp just put a bicycle wheel on a part of chair and made it as an artwork.

http://liminoid.net/breder/index.html

Here is a website I found that included Breder Hans’s intermedia artwork from 1964 to 2011, and I can see how his work, his boundary of art expands from year to year. As Breder said in a video on youtube, his art was basically based on his own experience and his own feelings from real world, for example: nature. From these Breder’s videos, I doubt that “intermedia” is strictly the same to everyone or not. Since meanings of intermedia (can an artwork be intermedia for some kinds of people but not intermedia for other kinds of people? Since there should be miscommunication happening among people.) This question stuck in my mind when I read the paragraph in the article. Is the boundary for intermedia based on meaning that from individual’s understanding or based on the artwork’s “meaning” itself? Can its definition be changed and be uncertained?