Over at Club Troppo, Nicholas Gruen says of the phrase “begs the question”
I love this term because it is such a simple, chummy way of naming something that’s maddening in is subtlety. To beg the question in its traditional meaning is to mistake the form of answering a question for its substance. One ‘answers’ the question by simply asking it again in another guise … Today, ‘begs the question’ is much more often used to mean ‘prompts the question’.
The problem with the old use of “begs the question” is that it makes no sense. It’s a literal translation of “petitio principii”. The problem is that “question” here means “conclusion” and “begs” means something like “asks the listener to assume”. The modern use is also nonsensical. My solution is to use “offers a circular argument” for the old use and “prompts the question” for the new one.