The problem is similar: in the department, we have people who study literature (and are thus armed with a lot of abstruse cultural and literary theory) and the people who create literature (and are thus armed with, er, so far as I can tell, pens). In addition, there’s a major trend toward separation, putting the writers in one section and the theorists into a melange of “cultural studies.” While I support interdisciplinary education—indeed, one of the best courses I took was team-taught by scientists, cultural theorists, historians and literary critics—the point was cross-pollination; the departments remained discreet, and what you were studying was added to by the intercession of these new voices. Making “interdisciplinary” the norm will set up new boundaries, similar to those you described between mathematics and programmers, that are no better than the “isolated department” scheme of the 1950’s.