Ed Sheeran’s ‘Thinking Out Loud’ Asks Jury to Mull Music Theory

Ed Sheeran will have to convince a New York federal jury next week that his 2014 hit song “Thinking Out Loud” didn’t copy from Marvin Gaye’s classic soul groove “Let’s Get It On,” the latest trial in an increasingly litigious music industry.

The rise in cases over the past decade has tasked judges and juries with delving into complex music theory and analyzing how musical building blocks—often uncopyrightable on their own—are strung together to create catchy tunes and hit songs.

The heirs of Ed Townsend, Gaye’s co-author for the 1973 tune, are arguing that Sheeran’s song copied the harmonic progression ...