Harmony is vertical sound meeting horizontal time
Harmony stacks pitches so they become chords, textures, and tonalities—then moves those stacks through time. Western theory obsesses over the blend, yet Carl Dahlhaus insisted harmony is a process: not chords alone, but how they progress, inseparable from counterpoint’s horizontal lines.
The word comes from Greek harmonia—“joint, agreement”—via harmozō, “to fit together.” Aristoxenus’s Elements of Harmony, often called Europe’s first treatise on the subject, nods to Pythagorean integer ratios (an octave as 1:2, a frequency doubling) yet insists the ear, not pure number, judges concord. Psychoacoustics still ties much listening pleasure to simple frequency ratios and the brain’s ease at “decoding” input; culture labels the pleasant consonant and the rough dissonant, though definitions shift by era. In common-practice classical style, tense dissonant sonorities typically resolve into restful ones; balance of strain and release, not endless sweetness, makes harmonization feel right. A wrong note that wrecks the whole may be called disharmonious rather than usefully dissonant.
Popular and jazz practice names chords by root and quality and loads “tensions”—extra members that clash with the bass. Counterpoint tracks independent melodies and is sometimes folded into harmonic thinking, sometimes opposed to it. The cliché that tonal harmony “began about 1600” when vertical writing replaced Renaissance counterpoint is, Dahlhaus argues, too neat: Bach’s tonal polyphony is no less polyphonic than Palestrina’s; older and newer types of both counterpoint and vertical craft succeeded each other. He also splits coordinate medieval–Renaissance linkage of adjacent sonorities from later subordinate, goal-directed tonality.
Western bias shows: many cultures practise vertical combination, while Hindustani and Carnatic traditions often rest on an unchanging drone fifth or fourth, treating simultaneity less as teleological progression than as raga’s melodic-modal web—with improvisation central where European art music, since the late nineteenth century, rarely invents freely. Early church polyphony favoured parallel perfect intervals for plainsong clarity in resonant cathedrals before English preference for sweeter thirds and sixths aided freer part-writing. Most Western chords remain tertian (built in thirds); quartal and quintal stacks offer alternatives, and even unison doubling counts as a harmonic interval—monophonic “harmony” when many voices share one pitch.
Source: Harmony
