Three, the Triad, is a perfect number, the number that distinguishes the Holy Trinity and the three theological virtues, of Faith, Hope and Charity. Three, in the Jewish Kabbalàh, also indicates the success of a project, the achievement of an objective. In the musical field, the Triad chord, in ancient times, was considered the manifestation of the divine Trinity and was, of course, capable of producing positive effects on the human soul, because the rhythmic ternary times were considered perfect, unlike the binary ones, which by their nature were imperfect. But also, under certain circumstances in the musical field, the number three has also assumed a ‘diabolical’ value.
Franz Liszt’s use of the Tritone to suggest Hell in his Dante Sonata (1855) (Public Domain)