In 2004, Malcolm Gladwell wrote an article which, among other things, explores why there are hundreds of varieties of mustard, but only one type of ketchup. (I first encountered it in the printed collection "What The Dog Saw" which is, I think, Gladwell at his finest. Freed from the burden of an overarching narrative, he can tell interesting stories 30 pages at a time.)
Part of the story is a meditation on the soul of