 Parallel to the Pythagorean tradition, an alternative approach sought to ground the laws of music in the way it appears to a competent listener, rather than in explanations from other domains of knowledge. This tradition attempted to provide descriptions of music in autonomously musical terms, and valued accordance with musical practice. This empirical approach to harmonics is in contrast to the mathematical approach adopted by the Pythagorean school (on the differences between the two schools, see Barker 2007 and Barker 1990: 3–8). The contrast between these two schools is of philosophical interest, insofar as it concerns the appropriate level of explanation for aesthetic phenomena. Additionally, mathematical harmonics often were taken to support the metaphysical worldview associated with the Pythagorean doctrine, whereas empirical harmonics tended to follow from an Aristotelian framework (see Barker 2007: chapter 4; Mathiesen 1999: 303).