Sense and Nonsense

     Nonsense verse has a prominent place in the poetry that mathematicians enjoy. Perhaps this is so because mathematical discovery itself has a playful aspect--playing, as it were, with non-sense in an effort to tease the sense out of it.      Lewis Carroll, author of  both mathematics and literature, often has his characters offer speeches that are a clever mix of sense and nonsense. For example, we have these two stanzas from "Fit the Fifth" of The Hunting of the Snark, the words of the Butcher, explaining to the Beaver why 2 + 1 = 3.