The question of the structural principle of harmony has been pondered throughout the 25 centuries of development of Western music theory. The overwhelming diversity of approaches resists categorization and, perhaps, makes it futile to search for a single governing principle for all music. Yet, from the bird’s view, one can notice a major discrepancy in its interpretation: on the one hand, there is a lofty philosophical idea that comes from Pythagorean mystical numerology; on the other, a very reasonable practical idea of the technique of connecting chords in a certain way, i.e., voice leading. Many theorists allowed for a leap of faith between the philosophical concept and its practical application. Fétis’s reaction to Rameau, Schenker’s reaction to Riemann and Kholopov’s reaction to Schenker may very well be the attempts to overcome a striking disconnect between the two aspects that in an ideal situation have to complement each other.