1. That there is a tradition in Western thought, stretching back at least to Pythagoras1, that the cosmos is structured according to the principles of musical harmony.

2. That as a corollary of the above, harmony in music is seen as both 'natural' 2 and (ethically) 'good'.3

3. This concept of celestial harmony has been commonly expressed by the metaphor of the 'music of the spheres'4, wherein the planets are associated with specific musical notes or melodic modes.5