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I was wondering something regarding the Back To The Future movie: Marty McFly is on stage and he's playing Johnny B. Goode. Marvin Berry phones his cousin Chuck Berry (the person who wrote the song).
Chuck hears the song and he uses it as a hit for himself. Now at this point Chuck learns the song through Marty but Marty learned it through Chuck. There is no actual creation moment of the song as both parties copied the song. So doesn't that mean the song can't exist at all? What kind of paradox would this be?