If I had to place this blog in a subject, it would probably fall under Music Criticism., in the sense that it is about me providing opinions and evaluation. The crucial question in this regard is, what is the philosophy underpinning this criticism?
In a very sketchy sense, postmodernism's greatest (not best) legacy may be the breaking down of the "grand narrative" of history. For those who studied music at school or university, the narrative reads something like: Bach cemented tonal procedures, Mozart and Haydn cemented sonata form structures; sonata form and tonality were stretched in the nineteenth century, first by Beethoven then by Wagner and Mahler, before Schoenberg created his serial methods, and so forth. Aesthetic judgment was argued to be tied in with modernist philosophy - i.e. Wagner and Schoenberg were "great" because they expanded and developed the musical domains inherited from their predecessors. I don't know much about the Felix Mendelssohn, but I would hazard that his critical reception was diminished because his music was especially influenced by Mozart. Only problem was Mozart had been and gone. Thus, we are encouraged to regard Berlioz as superior to Mendelssohn because of the former's orchestral innovations. Just a hunch.
The postmodernist response has been to question this teleological narrative and ask how various composers fitted into or reflected the culture and society in which they composed. In this sense, one cannot compare Beethoven to Wagner to Mendelssohn because, and here's the postmodern catchphrase, "everything can only be judged in its own context."
I won't mince my words: this attitude is the scourge of contemporary criticism. The reason? It denies the value of aesthetic judgments. If a piece of music can only be judged in its cultural context, then the context becomes the important factor, not the actual music. And what is a context? Some might say, all popular music since Elvis is a "context"; another person might disagree and say 1960s American rock n roll is a context; or rock n roll from 1961; or, rock n roll from Texas in 1961; or rock n roll from November 1961 from the southern towns of Texas; and so on, ad nauseam. The problem with this relativism is that we can create endless contexts and can then never judge anything against anything else.
This attitude manifests itself in too much popular music criticism. There are those who preface their columns or blogs with the statement "this is only my opinion/taste"; there are some who judge success only by commercial achievement; and there are a lot who regard criticism as entirely subjective and equate "good" with "like." With complete relativism, there is no longer any critical authority, just a mass of equally valid opinions.
The philosophical basis of arts criticism is the search for objective truth about what makes great art. Plato did not champion music in the Dorian mode (go 'Billie Jean' and 'Eleanor Rigby'!) because he necessarily liked it, but because he believed the music's effects would render the men of Ancient Greece more, well, manly. Music in the Phrygian mode (tough luck Metallica) was to be avoided because it would induce Dionysian frenzies (i.e. lots of drinking and sex). Thus music criticism should be seen as mirroring the difference between right and wrong.
This all works very well in theory. In practice, it's a tad more difficult. Evidently, no one since Plato has reached a definitive answer on what makes good music. Roger Scruton tried exceedingly hard in The Aesthetics of Music, and although there is a lot to commend, after 600-odd pages, it is a let down to hear that Mozart, Beethoven and co. are fab, The Beatles are great too, and everyone else since 1960 is pretty rubbish.
The first problem lies in the question: how is one supposed to definitively prove that this piece of music is better than another? The second main problem is that a bit of relativism doesn't go amiss. Without it, I probably wouldn't be studying popular music at university. Julian Johnson, in his excellent Who Needs Classical Music?, argues that we shouldn't try to compare Madonna with Mozart (even though that is what he implicitly does), and I agree. It is a rather pointless comparison because both inhabit different musical workds. But we should be able to argue whether Mozart, Madonna, or both, are worth of our attention - as academics, as critics, and as listeners. To do this, we need critics who can consider the bigger picture.
According to popmatters.com, Adele's 21 was one of their best albums of 2011; but where does 21 sit in the wider realm of history? (The response may come in a later post...) I read a journal article the other day discussed Korn as a the best exponent of nu-metal in the early 2000s; but why should I care about nu-metal compared to rock n roll or classical or soul? It is these questions that are the most difficult; but just because they are so, does not mean we should not try to answer them. As the musicologist Carl Dahlhaus put it, "relativism is open to anyone who wishes to avoid the convictions of their arguments." In other words, it is the easy option or a cop-out.
To try and tie these ramblings together a little, we don't need to reconstruct a grand old narrative, but there is good and bad music, and I sincerely do not believe that anyone is well-placed to make that judgment. Criticism should be about expertise, skill and knowledge and evaluations should be informed by logical reason and argument, not simply whether someone likes this band or that band. Every song and piece of music is equally deserving of a first listen and an evaluation, but that doesn't mean every song can be good in its own 'unique' way. Similarly, everyone is entitled to their opinion, but that doesn't mean everyone should be taken seriously. To paraphrase George Orwell, all tastes are equal, but some are more equal than others.
And that is my philosophy in a nutshell.