Rhetorical question

A rhetorical question is a figure of speech in the form of a question. It is a question that is asked in order to make a point: it does not need a reply.
The question is used as a rhetorical device or tool. The question is posed for the sake of persuasion, or to encourage the listener or reader to consider a message or viewpoint.
Suggested dialogue.
Rhetorical questions suggest a dialogue which does not really exist. The speaker both asks and answers the question himself. A rhetorical question is often a statement in the form of a question.
For example, in "Can't you do "anything" right?", the words are not intended to start an investigation or to invite any response at all. What the words actually mean could change according to circumstance. It could be a little joke between friends, or it could be an insulting criticism. Generally, it would be taken to mean "You can't seem to do anything right".
The role of context is always important if someone asks "What does that mean". Consider this question: "Do you think this treatment is just?". There is no way of knowing whether this is a genuine question or not, because we do not know what the circumstances are. This is true of many kinds of communication, that what they mean varies according to circumstance.
On the other hand, "Is it right for a murderer to be allowed out of prison after only ten years?" clearly asks for the reply "No!". This is because the questioner has "signalled" what answer is expected. A neutral way to describe the situation might be: "A convicted murderer spends at least ten years in jail".