Begging the question

Begging the question (Latin: petitio principii) 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?
   
2. - Because he is a traveler.
   
3. - But he did not ask for passports. Why do you think he is traveling?
   
4. - 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.

See Also

Warning: This argument represents a Begging the question.

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• Logical fallacy