The Medieval Ban Against the “Devil’s Tritone”: Debunking a Great Myth in Music Theory

Music lives deep with­in us, in the mar­row of our evo­lu­tion­ary bones, tap­ping into “this very prim­i­tive sys­tem,” says British musi­col­o­gist John Deathridge, “which iden­ti­fies emo­tion on the basis of a vio­la­tion of expectan­cy.” In oth­er words, our brains are pre­dis­posed to hear cer­tain com­bi­na­tions of sounds as sooth­ing and oth­ers as dis­turb­ing. When we plot those sounds on a staff, we find one of the most dis­so­nant, yet intrigu­ing, com­bi­na­tions, what can be called an aug­ment­ed 4th or dimin­ished 5th but isn’t quite either one. But it’s much bet­ter known by its medieval nick­name, “the devil’s tri­tone” (or “devil’s inter­val”), a sequence of notes so sin­is­ter, they were once banned in the belief that they might con­jure Lucifer him­self…. Or so the sto­ry goes.

The truth is less sen­sa­tion­al. “To the cha­grin of many a musi­cian want­i­ng to tap into a badass rebel streak in music’s DNA,” James Ben­nett writes at WQXR, “there aren’t any records to sug­gest any rogue medieval com­posers took a hike to Perdi­tion after using this spooky, dev­il­ish inter­val.” In oth­er words, no one seems to have been tor­tured, impris­oned, or excom­mu­ni­cat­ed for a musi­cal arrange­ment, all inter­net asser­tions to the con­trary notwith­stand­ing. But the asso­ci­a­tion with the dev­il is his­tor­i­cal. In the 18th cen­tu­ry, the tri­tone acquired the name dia­bo­lus in musi­ca, or “the dev­il in music,” part of a mnemon­ic: “Mi con­tra fa est dia­bo­lus in musi­ca” or “mi against fa is the dev­il in music.”

If you’re already versed in music the­o­ry, you’ll find this tech­ni­cal expla­na­tion of the “devil’s inter­val” by musi­cian Jer­ry Tachoir help­ful. In the video above, bass play­er Adam Neely debunks the myth of the dev­il’s tri­tone as an actu­al curse. But his expla­na­tion is more than “one long, ‘Um, Actu­al­ly,’ ” he says. Instead, he tells us why the tri­tone is a musi­cal bless­ing, and was thought of as such a thou­sand years ago. His expla­na­tion also gets a lit­tle tech­ni­cal, but his visu­al and musi­cal demon­stra­tions make it fair­ly easy to fol­low, and if you don’t absorb the the­o­ry, you’ll pick up the true his­to­ry of the “dev­il’s tri­tone,” begin­ning with the Greek thinker Aris­tox­enus of Tar­en­tum, one of the first to write about the uncom­fort­able dis­so­nance of a note sit­ting between two oth­ers.

The tri­tone is what musi­col­o­gist Carl E. Gard­ner called a “depen­dent” chord, one char­ac­ter­is­tic of ten­sion. We may not reg­is­ter it con­scious­ly, but it primes our brains with anx­ious expec­ta­tion. “The rea­son it’s unset­tling is that it’s ambigu­ous, unre­solved,” says Ger­ald Moshell, Pro­fes­sor of Music at Trin­i­ty Col­lege in Hart­ford, Conn. “It wants to go some­where. It wants to set­tle here, or [there]. You don’t know where it’ll go, but it can’t stop where it is.” We hear this irres­o­lu­tion, this “dev­il” of musi­cal doubt in com­po­si­tions rang­ing from The Simp­sons theme to the cho­rus of Pearl Jam’s “Even­flow” to Camille Saint-Saëns’ “Danse macabre,” a piece of music that may not actu­al­ly con­jure evil, but sure sounds like it could if it want­ed to.

Relat­ed Con­tent: 

How to Lis­ten to Music: A Free Course from Yale Uni­ver­si­ty

John Coltrane Draws a Pic­ture Illus­trat­ing the Math­e­mat­ics of Music

How Ornette Cole­man Freed Jazz with His The­o­ry of Har­molod­ics

Josh Jones is a writer and musi­cian based in Durham, NC. Fol­low him at @jdmagness