Some years ago, under the influence of positivist philosophy, it used to be the fashion to consider statements in a three-fold classification: True, False, Meaningless. This trichotomy is still useful in the positive science to which it refers. If our arguments have empirical meaning, they can be tested by experimental or other factual evidence; if tests are impossible, then we are making statements that can have no consequences since the possibility of factual inferences from our statements provides an opportunity for test.
Subsequent reflection convinced many that "meaningless" and "nonsense" do not mean the same thing. A collection of symbols BJY&! % ′KB?D" # is not only meaningless but nonsense. So are self-contradictory statements like: "It will rain today and it will not rain today." These may be safely ignored since the words and symbols communicate nothing. But what of this passage from The Art of the Fugue?
These symbols have several meanings, yet none of them are factual: They are imperatives to produce a set of as yet unheard sounds. They have an anagrammatic meaning, BACH, in . . .