Kuhn made several notable claims concerning the progress of scientific knowledge: that scientific fields undergo periodic "paradigm shifts" rather than solely progressing in a linear and continuous way; that these paradigm shifts open up new approaches to understanding that scientists would never have considered valid before; and that the notion of scientific truth, at any given moment, cannot be established solely by objective criteria but is defined by a consensus of a scientific community. Competing paradigms are frequently incommensurable; that is, they are competing accounts of reality which cannot be coherently reconciled. Thus, our comprehension of science can never rely on full "objectivity"; we must account for subjective perspectives as well.A friend of mine gave me a copy of the book way back in the 70s or 80s and I found it fascinating. But as time goes on I am less and less convinced of its application to science, but more and more see its potential application to aesthetics. Science is about objective reality and a paradigm shift is really nothing but seeing all the data from an entirely new angle. The only thing that might be subjective there is the angle. But aesthetics? That's a whole 'nother thing.
I think that what we see in the dislocations of music history might well be described as a "paradigm shift". For example, a famous one is the shift from the 16th century way of structuring music based on equal, independent voices in a context of smoothly flowing, consonant counterpoint to the 17th century way based on the polarity of soprano and bass lines with other voices used to fill out the harmony and the de-emphasis on counterpoint and the increased importance of dissonance. Or the shift from the 19th century romantic ideals of naturalism, richly textured harmony and orchestration to the early 20th century practices of rhythmic intensity, atonality and artificiality.
Examples? Sure, we got examples! Here is the 16th century texture with a madrigal by Morley:
And this is the 17th century texture with a piece by Caccini, one of the inventors of 17th century style:
Here is the 19th century with an overture by Brahms:
And the 20th century with a string quartet movement by Bartok:
Plainly these pieces are structured in very different ways with very different aesthetic goals and need to be listened to in different ways. In Kuhn's terms these competing paradigms are incommensurable. But in aesthetics, my brand of aesthetics at least, judgments and evaluations are always necessary if only because we have to choose what to listen to out of an immensity of music. I think it is possible to evaluate pieces within their paradigm: there are better and worse examples of 19th century music, for example. But is it possible to evaluate different paradigms? That is something that is much harder to argue for. How do you evaluate paradigms? Not by different paradigms, surely. Are there aesthetic standards that transcend any particular paradigm? I think there must be, because we can come up with great works of music from all sorts of different times and places. Deciding what makes these works 'great' might be pretty tough though, as their qualities are, yes, incommensurable.
Just another one of those mysteries of music I will say...