rhetorical question

The rhetorical question is usually defined as any question asked for a purpose other than to obtain the information the question asks. For example, "Why are you so stupid?" is likely to be a statement regarding one's opinion of the person addressed rather than a genuine request to know. Similarly, when someone responds to a tragic event by saying, "Why me, God?!" it is more likely to be an accusation or an expression of feeling than a realistic request for information.
Apart from these more obviously rhetorical uses, the question as a grammatical form has important rhetorical dimensions. For example, the rhetorical critic may assess the effect of asking a question as a method of beginning discourse: "Shall I compare thee to a summer's day?" says the persona of Shakespeare's 18th sonnet. This kind of rhetorical question, in which one asks the opinion of those listening, is called anacoenosis. This rhetorical question has a definite ethical dimension, since to ask in this way generally endears the speaker to the audience and so improves his or her credibility or ethos. The technical term for rhetorical questions in general is erotema.

See Definition