Remixing is a folk art but the techniques involved — collecting material, combining it, transforming it — are the same ones used at any level of creation. You could even say that everything is a remix.
Our system of law does not acknowledge the derivative nature of creativity. Instead, ideas are Regarded as property, as unique and distinct boundaries With the original lots. But thoughts are not so tidy. They're layered, they're interwoven, they're tangled. When the system and Conflicts With The reality ... the system starts to fail.