But 4"33' wasn't so much concerning itself, it was a cry for people to not listen to the sound environment of the concert hall, but to any sound envrionment in general. It was conceptual only in the sense that it was concerning aestheticsm, and not theory. It was only given a set time period and a place as a composition to stress a point, to articulate an idea. The piece itself is extrememly limited, but that was not the point. It was saying that there are or at least should be no sonic limitations for musicians to work inside, it was about listening to the sounds of the world - and as an agenda i think Cage was successful.
The way that Varese differed from Cage, apart from the obvious, was that Cage brought the use of aleatoric sound outside the orchestral context, but didn't quite successfully bring it all the way out, that was done by 70 years of experimental music that followed. He was merely using the tradition of composer-score-performer-audience as a basis by which to articulate his point, and did it very well. If one then thinks about that relationship as a limition then we must bring in Roland Barthes The Death of the Author, but i haven't read that and don't know anything about it so lets forget it

More importantly i think the compression of Art and Music IS possible because all it requires is for one to forget those ridiculous, dogmatic labels and just treat what they are viewing as an object instead of an art-object, for them to appreciate it as sound instead of music. But at the same time, what Cage was stressing was that we can keep the label of Music and apply it to everything and it will work itself out - but ultimately it didn't work itself out, for in order to do so the idea would have to hit the mainstream consciousness and everybody in the world would have to accept the fact that anything could be music and we could go from there. What essentially holds Cageian philosophy back is the fact that most people don't know about it, and because they don't know about it they will continue to express their view of music as having strucutal, compositional limitations and this will ultimately effect the consensus and inherent definition of what Music itself is.
And if it to enjoy a piece of aestheticism one has to define for themselves what traditional lineage it belongs to (ie reaction ajusts accordingly) then more work has to be done to stop this meaningless defining position and for people to simple forget about it and enjoy it for what it is. Then this brings the idea of the elimination of the space that exists between an artwork and the viewer, whether it be because of tradition, dogma, or that the piece of art is a icon of consumer capitalism (whatever tickles your fancy

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Lastly there are some good and bad things about limitations. The good things are many. For instance, if you think about genres of music, dance and 'urban' music being a perfect example - a genre itself is merely a template, a set of guidelines, a set of limitations by which to go about creating a piece of music. The period of deterritorialisation that occurs in music culture happens when everybody basically goes about finding all the many possibilities within that group of limitations, filling them out, exploiting the guidelines. Then you think about music synthesis practically - if one has a monumental amount of equipment and software that they hardly know how to use, what they come up with will probably be nothing compared to what a guy who knows how to use Fruityloops really well does. And then you think of Dogma'95. Thomas Vinterberg, on creating Festen, remarked how he found the Vow of Chastity to be almost liberating rather than restricting, because he was able to make the best that he could inside limitations, instead of being exposed to limited possibilites and getting confused. So limitations can help the creative process, which can, most of the time, be very hectic, chaotic, and frustrating
BUT, at the same time you cannot deny that limitations in the melodic, rhythmic, timbral and textural sense can bring about standardisation, dogmatic stagnation and overall boring creation of the same old thing. Isn't it the most honourable and greatest motivation one can have for creating art to make something 'new' instead of simply creating something which has been done so many times before.