Begging the Question
You may have missed the Great Begging the Question Debate over at Kevin Drum's Political Animal. To recap, Kevin used the Phrase to mean, 'raising the question'. He was immediately pounced upon by purists (yes, I joined the howling mob) who insisted that the Phrase meant 'you have proved nothing, because you have assumed your consequent', or that what you were pretending to prove was in fact buried in your assumption and you have committed a logical fallacy. Kevin said something to the effect that okay, okay, the phrase has a strict logical meaning but since most people now use it to mean 'raising the question', his usage is equally correct. This didn't appease the mob.
Today he good-naturedly points us to this, which settles the debate once and for all, I hope.