Begging the question

Begging the question is a type of informal fallacy in which an implicit premise would lead directly to the conclusion. That is, a thesis is shown assuming that it is already valid. A fallacy of petitio principii, or "begging the question" is committed when a proposition that requires proof is assumed without proof.

It is a fallacious rhetoric sometimes deliberate, sometimes used to put a quick end to the debate as in a discussion with a child.

Examples

 * "I'm right because I'm your father, and the parents are always right".


 * After an armed robbery, a victim asks for the assaulted partner:


 * 1) - Why you gave our passports along with the money?


 * 1) - Because he is a traveler.


 * 1) - But he did not ask for passports. Why do you think he is traveling?


 * 1) - Because he has a passport.


 * Here's an attempt to prove that Chavez says the truth:
 * 1) - Suppose Chavez does not lie when he speaks.
 * 2) - Chavez is talking.
 * 3) - Therefore, Chavez is telling the truth.


 * In evolutionary discussions, an example might be:
 * 1) This organism is fit
 * 2) How do you know that it's fit?
 * 3) Because it survived


 * In a meeting room
 * 1) Speaker: you will notice that only dark-haired males are present
 * 2) Attendee: The sign outside said "Dark-Haired Males here--->"


 * In Astrology
 * 1) What is your sign?
 * 2) Virgo
 * 3) I might have guessed that. Most beautiful women are Virgos
 * 4) So if I check the latest Miss Universe, most of them are Virgos?


 * Christianity
 * 1) Jesus rose from the dead
 * 2) No he did not
 * 3) Why do you say that?
 * 4) Because people don't rise from the dead


 * Origin of life
 * 1) Life came from non-living material
 * 2) How do you know that?
 * 3) Well, we're here, aren't we?


 * In geological discussions:
 * 1) I just found a giant dragonfly fossil
 * 2) How old is that dragonfly?
 * 3) 200 million years!
 * 4) How do you know that?
 * 5) Because of the layer of rock I found it in
 * 6) How old is that layer of rock?
 * 7) 200 million years old
 * 8) How do you know that?
 * 9) Because it has insects in it


 * The Scientific Method
 * 1) I hypthothesized that only striped rats would complete the maze
 * 2) How many rats did you use?
 * 3) 1000 rats
 * 4) How many completed the maze?
 * 5) Fifty
 * 6) How man of them were striped?
 * 7) All of them
 * 8) How many were not striped?
 * 9) No non-striped rats completed the maze
 * 10) How many non-striped rats did you start out with?
 * 11) None of them

Formal example
Formally speaking this fallacy has the following structure. For some proposition p


 * p implies q
 * q implies r
 * r implies p
 * suppose p
 * therefore, q
 * therefore, r
 * therefore, p.