Skip to main content
Glite Dictionary
petitio

petitio

1 9.9
Making an argument that already assumes the answer
  • noun
  • /pəˈtɪʃioʊ/
  • Formal
translation icon : petitio
  • The professor explained that a petitio occurs when someone concludes that their claim is true based solely on the premise they've already assumed.

Examples

  • Pocket OED: 1925, Petitio

    Blog text (33)

  • It's a debating fallacy also called "petitio principii" where you assume something is true, then you say it's true because earlier you assumed it.

    Blog text (25)

  • Yup, I was going to raise the same issue—"begs the question" is most easily thought of as "beggars the question" (or petitio principii for any Latin scholars who might be lurking among us).

    Blog text (30)

  • In his argument, he committed a petitio by assuming that all politicians are corrupt without providing evidence.

  • The speaker's reasoning contained a petitio when he stated that the policy is effective simply because it is the best option available.

Synonyms

petitio principii
vspetitio
  • Formal
9.9

To use reasons that already assume the thing you must prove

is the identical idea but expressed with a more technical Latin term
hysteron proteron
vspetitio
  • Literature
9.9

An error in reasoning that assumes the conclusion is already true

is the logical error of assuming what one must prove

Compounds

petitio principii
  • Formal
9.9

To use reasons that already assume the thing you must prove

Surface Forms

petitio singular
petitios plural

Etymology

Petitio comes from the Latin verb petere, meaning 'to ask' or 'to seek', and it is the same root as the English word petition, which is a formal request. A helpful way to remember the idea is 'asking for the answer': petitio is the error when an argument quietly uses the thing it should prove, so the conclusion is assumed rather than shown.