Begging the question (petitio principii)

==Definition==
A person commits the fallacy of Begging the Question when the arguer presents an inadequate premise as adequate and restates it as the conclusion.
:Pattern: P because P
==Example==
This ad "Baby, Baby - Prob 8" commits the fallacy of Begging the Question.
thumb|left|300px|Baby, Baby - Prop 8
This commercial is trying to persuade people to vote yes on prop 8. The ad opens with a series of photos of babies participating in various activities such as swimming, eating, and drinking out of a Sippy Cup. The babies are also shown in various locations, for instance playing on a staircase, crawling in a library, on dad’s shoulders, on a swing, having a bath and what is presumably in their homes. In every photograph, the children are presented as happy within their current environment. The song “Baby, Baby” by Amy Grant plays in the background. Some of the photos include adults, presumably the babies' parents, but most showed the babies alone. The ad commits the fallacy of Begging the question when it concludes that every “baby has a right to a mommy and a daddy.” The commercial follows the pattern of this fallacy, by asserting, albeit implicitly, that the fact that babies are cute is adequate support for the conclusion that babies have a right to a mom and dad. The conclusion that babies have a right to a mom and dad is then implicitly supplied as evidence for the further conclusion that same-sex marriage should be illegal, committing the same fallacy a second time. It begs the question of what the rights of babies to a mom and dad have to do with same-sex marriage being legalized.
==Other examples==
This ad for "Coca-Cola" commits the fallacy of begging the question.
thumb|300px|left|Coca-Cola
As the ad starts, video clips show different athletes participating in various sports, including golf, race car driving, baseball, swimming, and bull riding. There are quick interjections of coke bottles being opened and coke poured into glasses. In the background a “catchy,” upbeat tune plays. The music seems to appealing to comradery between the athletes and fans. The only words in the entire ad appear in the last ten seconds, and this is where the fallacy of Begging the Question comes in. The narator asserts: “Coca-Cola has the taste you never get tired of, always refreshing; that’s why things go better with Coke, after Coke, after Coke.” What makes this a fallacy is the idea of things always going better with the consumption of more Coca-Cola. It begs the question why do refreshing Cokes make things go better? The ad follows the pattern in that Coke is the best because Coke makes things better, which is just another way to state that Coca-Cola is the best.
This ad for "Old Gold Cigarettes" commits the fallacy begging the question with a different pattern.
X is the best
Because the best is X
thumb|300px|left|Old Gold Cigarettes
This ad begins with Dennis James, a television actor and announcer, introducing two dancing cigarette cartons that portray the cigarette brand Old Gold. In the ad Dennis James states that the cigarettes are “a treat, not a treatment” because there’re made by “tobacco men”, not “medicine men”. The ad commits the fallacy of Begging the Question by stating “To give you the cigarette that treats you better in every way, because in every way it is a better cigarette.” The premise of this statement that it “treats you better” and the conclusion of “it’s a better cigarette” can substitute each other and the argument that the ad makes still works. Dennis James uses his authority as a T.V. spokesman to make a claim about Old Gold cigarette brand. The viewer can only take his word that the claim that Old Gold is “a better cigarette” is adequate, although Dennis James’ authority itself is possibly inadequate to formulate this claim. The viewer is supposed to take the spokesman’s word that the cigarette is better than other brands, because he is not proving that any part of Old Gold cigarettes have any better qualities. The cigarette cartons then finish their dance and the ad concludes with Dennis James, reappearing back on screen, looking over his shoulder at the camera, sitting in a luxurious arm chair, and holding a cigarette reminding people to smoke Old Gold.