Pharrell Williams, Robin Thicke, and Clifford Harris, Jr. (a/k/a T.I.) have taken Marvin Gaye’s family to court after receiving threats from the family that the hit song Blurred Lines was a knockoff of Gaye’s Got to Give It Up. The contemporary crooning trio filed a motion for summary judgment hoping this would settle the dispute. But U.S. District Judge John A. Kronstadt has written that he is likely to deny the motion, finding genuine issues of material fact that the songs were substantially similar as to protected elements. The ruling is not a full-on defeat, and it is unclear if the case proceeds to trial, though Kronstadt also has ruled on other case motions to compel further responses.  The case has attracted considerable attention, with both sides using musicologists and mashups to debate copyright law. Gayes’s family accuses Thicke of having a “Marvin Gaye fixation.”  What’s at legal issue? Give a listen and compare the songs in dispute: