Like scientists, perhaps, music theorists address epistemological issues only when the truth-value of their work no longer seems self-evident to them. And if this is the case—if music-theoretical concern with epistemology is at root an expression of anxiety—then we have a fundamental problem in trying to unravel the epistemological underpinnings of music theory: when theorists are confident of the epistemological status of their work they will say nothing about it, whereas when they do talk about it we can deduce they are not quite sure what they are saying.
Nicholas Cook, “Epistemologies of Music Theory”, in The Cambridge History of Western Music Theory, edited by Thomas Christensen