Doug Hagler describes genius as:
Level 1 - someone saying something no one can understand
Level 2 - someone who says something everyone can understand
Level 3 - someone who says something intelligent everyone can understand
The point of this explanation of genius in terms of music can be explained this way:
Level 1 - music on which is complex on the page that listeners do not understand (or enjoy)
Level 2 - music that people enjoy but has no underlying complexity
Level 3 - music that is both enjoyable and has complexity
During a recent conversation at lunch I was discussing this sort of analysis of music and came to the realization that Pachelbel's Canon in D is an example of Level 3 genius. It is both a beautiful piece of music, enjoyed by millions of people, (it is continually performed at weddings because of it's beauty), but it also contains mathematical relationships that are beautifully complex. Bach has numerous fugues, inventions and other works that have this duality, complexity in form and structure that is still pleasing to listen to.
Without naming names, there are numerous other "famous" composers that (IMHO) lie in the Level 1 of musical genius. Their music may have an underlying complexity, but it really isn't pleasing. Yes, some musicians like it, but I contend that is mostly because of the musical complexity and not because the music has any pleasing aural sense. Just because something is complex doesn't make it pleasing to listen to.
There are also a broad number of composers who write music pleasing to listen to but don't really go much further in terms of complexity.
The pop music world is criticized in academic circles because of the proclivity to use only basic three chords and be very repetitive in lyrics and melody. Compare most pop songs with German lieder by Schubert or Mahler and you'll discover a complexity in the lieder generally not found in pop music. That doesn't mean pop music isn't pleasing or good. It just isn't in the same level of "genius" as that of Schubert or Mahler. Having said that, I have no doubt there are pop songs that do have complexity to them, but because they fall in the "pop" realm they haven't been analyzed to discover their layered structure.
The goal of a classical composer should be to create music that fills both criteria of Genius Level 3: pleasing to listen to and complex in structure.Part of my educational process has been to discover what complex structures other great composers use within their music. The next step (for me) is to try and incorporate those elements into my own pieces, consistently and pleasingly.