"The problem with listening, of course, is that we don't. There's too much noise going on in our heads, so we never hear anything. The inner conversation simply never stops. It can be our voice or whatever voices we want to supply, but it's a constant racket. In the same way we don't see, and in the same way we don't feel, we don't touch, we don't taste...The essential activity of listening requires at least a minimal point of attention. And that allows us to keep the flow of attention uninterrupted."
See also: "A Conversation with Philip Glass," Studio 360, September 14, 2012