Thats bullshit, nearly every rock band ever has gone with the non theoretical approach. 'GOFONES go by what sounds good blah blah; The strokes use theory so theyre shit.' No the strokes probably know bugger all about theory or using their ears, thats why they sound shit and predicatable and boring. Composers use a theoretical approach. I can write music with basslines and guitar lines (which have been tried and tested) without touching an instrument, not by sticking to harmony rules but just hearing the parts in my head. For some reason I find this approach gives you far more articulate and pronounced rythms plus a whole wedding celebration of other musical advantages. In theory, with a couple of books at your side, you could write some insane music, music you wouldnt ever see or realise sitting in your bedroom stuck in a rut.