A rhetorical question is one that requires no answer. It is a rhetorical device. Rhetoric involves debate, speechmaking, constructing logical and coherent thoughts and using them to baffle and irritate those unfortunate enough to be caught in one's general vicinty. The Phonograph, once known as a "Talking Machine" is not, strictly speaking, a rhetorical device. But it can be used as one, in a pinch. The pinch is a small unit of measurement used in Cooking. I'm not sure of the Metric equivalent. When the Music is Really Cooking, the musicians are sometimes Baked. The Birth Of The Cool is one example of this phenomenon.