 Some theorists (including Schenker or Maurice Emmanuel) considered that overtones higher than the fifth (or sixth) could not be heard and that no dissonance could ever be justified by the harmonic series.Maurice Emmanuel wrote

This statement has been one source of Jacques Chailley's evolutionary theory, describing music history as the progressive understanding and usage of higher overtones.The theory of the Chord of Nature was fashionable in the early 20th century.