For Pythagoras, both mathematics and philosophy are born from the structural
nature of music. And with the regulative measure following from an understanding
of the political/ethical effects of musical tuning, Plato builds an ideal
musical city founded on the same well-tempered measure and, in a similar
fashion, Aristotle invokes the ethical ideal of musical harmony (Nicomachean
Ethics, 1131 a-1134 b).
I commend reading the Notes from Babette Babich essays
Practice of Music in Plato, Nietzsche,