Stockhausen in his closing speech of the Stockhausen Courses Kuerten in 2004:
Music is a very subtle medium. So please don’t forget that we musicians have as matter, as material, air. Already painters and sculptors have harder material. They need to have colours and paper, metal and God knows what. But we have air. So, for a whole life, we do nothing but form and shape air, making invisible sculptures and compositions of movements in air. We have the most subtle medium that exists in the universe. And we have a great responsibility to continue this art music. So, don’t listen to all the other temptations such as we should have more music for the body in order to have a sort of acoustic gymnastics. This is also necessary but it is not what we are doing here.
And don’t forget that we make contact through music with the other world. All the time… with invisible angels, as today.