A rhetorical question is a figure of speech in the form of a question that is asked in order to make a point. The question is used as a rhetorical device, posed for the sake of encouraging its listener to consider a message or viewpoint. Though these are technically questions, they do not always require a question mark.
For example, the question "Can't you do anything right?" is asked not to gain information about the ability of the person being spoken to, but rather to insinuate that the person always fails.
While sometimes amusing and even humorous, rhetorical questions are rarely meant for pure, comedic effect. A carefully crafted question can, if delivered well, persuade an audience to believe in the position(s) of the speaker.
In simple terms, it is a question asked more to produce an effect than to summon an answer.
Different forms 
Negative assertions 
Often a rhetorical question is intended as a challenge, with the implication that the question is difficult or impossible to answer. Thus the question functions as a negative assertion. For example, What have the Romans ever done for us? (Monty Python's Life of Brian) should be read as The Romans have never done anything for us. Similarly, when Shakespeare lets Mark Antony exclaim: Here was a Caesar! when comes such another? (Julius Caesar, Act 3, scene 2, 257), it functions as an assertion that Caesar possessed rare qualities that may not be seen again for a long time, if ever.
Such negative assertions may function as positives in sarcastic contexts. For example, when a speaker repeats a statement reported to have been found true and adds a sarcastic Who knew?, the question functions as an assertion that the truth of the preceding statement was – or should have been – already utterly obvious: Smoking can lead to lung cancer. Who knew?!"
Rhetorical questions as metaphors 
One common form is where a rhetorical question is used as a metaphor for a question already asked. Examples may be found in the song Maria from the 1959 Rodgers and Hammerstein musical, The Sound of Music, in which the How do you solve a problem like Maria? is repeatedly answered with another question: How do you catch a cloud and pin it down?, How do you keep a wave upon the sand? and How do you hold a moonbeam in your hand? These responses may be taken as asserting that "the problem of Maria" cannot be solved; and furthermore the choice of cloud, wave and moonbeam as metaphors for Maria give insight into her character and the nature of the problem.
In the vernacular, this form of rhetorical question is most often seen as rhetorical affirmation, where the certainty or obviousness of the answer to a question is expressed by asking another, often humorous, question for which the answer is equally obvious; popular examples include "Does a bear shit in the woods?" Is the sky blue? and Is the Pope Catholic?
Other forms 
Sometimes the implied answer to a rhetorical question is "Yes, but I wish it were not so" or vice versa:
- O mighty Caesar! dost thou lie so low?
- Are all thy conquests, glories, triumphs, spoils,
- Shrunk to this little measure?
- (Shakespeare, Julius Caesar, III.i.148)
Another common form is the expression of doubt by questioning a statement just made; for example, by appending the following to a sentence: or did he?, or is it?, etc.
- The butler did it... or did he?
It is also common to use a rhetorical question to bring an end to a debate or to finalize a decision. For example, when internally deciding whether to perform an action, one may shove aside the dialogue with a simple, "Eh, why not?" or "What the heck?"
Rhetorical Answers 
Another form of rhetoric can be used within conversation is that of an answer. A rhetorical question is one that is asked already knowing the answer. Through the property of literary inverse the rhetorical answer was created. The first known use was in 1986 by the famous author Lee Paul's novella "Time to Burn". Since then it has been used little. For the most part one would use it to make a statement in which the implied question goes without saying.
Depending on the context, a rhetorical question may be punctuated by a question mark (?), full stop (.), or exclamation mark (!), but some sources argue that it is best to use a question mark for any question, rhetorical or not.
Rhetorical questions may be signaled by marker phrases; questions that include "after all", or "by any chance" may be intended as rhetorical.
Written lists of rhetorical questions within a sentence require question marks, but do not require quotation marks. "Would he? Could he? Should he? she asked." 
In the 1580s, English printer Henry Denham invented a "rhetorical question mark" for use at the end of a rhetorical question; however, it died out of use in the 17th century. It was the reverse of an ordinary question mark, so that instead of the main opening pointing back into the sentence, it opened away from it.
"The effectiveness of rhetorical questions in argument comes from their dramatic quality. They suggest dialogue, especially when the speaker both asks and answers them himself, as if he were playing two parts on the stage. They are not always impassioned; they may be mildly ironical or merely argumentative: but they are always to some extent dramatic, and, if used to excess, they tend to give one’s style a theatrical air." 
"Rhetorical questioning is…a fairly conscious technique adopted by a speaker for deliberate ends, and it is used infrequently, proportional to the length of the dialogue, oration, or conversation." 
See also 
- Hypothetical question
- Suggestive question
- Complex question
- Double-barreled question
- Loaded question
- Performative contradiction
- Gideon O. Burton, Brigham Young University. "Rhetorical Questions". specialized language definitions. Retrieved 2007-10-19.
- "Rhetorical Questions". The Library of Rhetoric.
- Powell, Chris; Paton, George E. C. (1988). Humour in society: resistance and control. Macmillan. p. 67. ISBN 0-333-44070-6.
- Moon, Rosamund (1998). Fixed expressions and idioms in English: a corpus-based approach (Oxford studies in lexicography and lexicology). Oxford University Press. p. 158. ISBN 0-19-823614-X.
- Fergusson, Rosalind; Partridge, Eric (1994). Shorter dictionary of catch phrases. Routledge. p. 25. ISBN 0-415-10051-8.
- http://www.whitesmoke.com/punctuation-question-mark.html#rhe Whitesmoke
- Javier Gutiérrez Rexach, "Rhetorical Questions, Relevance and Scales", Ohio State University, 1998
- 6.126 and 6.56 Chicago Manual of Style 15th ed. 2003, University of Chicago Press.
- Truss, Lynne. Eats, Shoots & Leaves, 2003. p. 142. ISBN 1-59240-087-6.
- Gardiner, J (1907). "Manual of Composition and Rhetoric". Ginn & Company. Retrieved 23 April 2011.
- Boyd, Boyd (1997). Electronic Discourse: Linguistics Individuals in Virtual Space. Albany: State University of New York Press.
|Look up rhetorical question in Wiktionary, the free dictionary.|
- What is a rhetorical question?
- Audio illustrations of the rhetorical question
- A short definition of the term
- Paul Brians, Washington State University. "Common Errors in English". Grammatical Errors in the English Language. Retrieved 2007-10-19.
- Roger Kruez, Aaron Ashley, and Kathryn Bartlett, University of Memphis. "Twisting Arms: Figurative Language Effects in Persuasive Discourse". psychology research paper. Retrieved 2008-03-27.