As a musician and a “recovering” lawyer, I understand the arguments from both sides. However, I believe that all art and all music is derivative to some degree. Taking art and calling it property defeats the purpose of art, which is to share with others and create community. I assume that Marvin Gaye and his co-writer hoped that the songs would be heard. They must expect, then, that the songs will influence others and become part of their musical lexicon. Furthermore, if you look at the purpose of copyright, as set forth by the authors of the U.S. Constitution, it was to protect creative thought, not property. In fact, the term of copyright in the first American copyright laws was 14 years and could only be renewed if the author was still alive at the end of the original term. Why? Because you can’t be creative after you’re dead. Life of the author plus 70 years (the current term of copyright) is a travesty and constitutes theft of the commons.