petitio principii

[ pi-tish-ee-oh prin-sip-ee-ahy; Latin pe-tee-ti-oh pring-kip-i-ee ]

/ pɪˈtɪʃ iˌoʊ prɪnˈsɪp iˌaɪ; Latin pɛˈti tɪˌoʊ prɪŋˈkɪp ɪˌi /

Save This Word!

noun Logic.

a fallacy in reasoning resulting from the assumption of that which in the beginning was set forth to be proved; begging the question.

QUIZ

WILL YOU SAIL OR STUMBLE ON THESE GRAMMAR QUESTIONS?

Smoothly step over to these common grammar mistakes that trip many people up. Good luck!

Question 1 of 7

Fill in the blank: I can’t figure out _____ gave me this gift.

who

whom

TAKE THE QUIZ TO FIND OUT

Origin of petitio principii

1525–35; <Medieval Latin petītiō prīncipiī, translation of Greek tò en archêi aiteîsthai the assumption at the outset

Words nearby petitio principii

petit feu, petit four, petition, petitionary, petitioner, petitio principii, petit jury, petit larceny, petit mal, petitor, petit point

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use petitio principii in a sentence

Is it not then a petitio principii to say, that the fact ought to be disbelieved because the induction opposed to it is complete?
A System of Logic: Ratiocinative and Inductive|John Stuart Mill
The following are additional instances of Petitio Principii, under more or less of disguise.
A System of Logic: Ratiocinative and Inductive|John Stuart Mill
But if the words are cited as the proof, it would be a clear petitio principii, though there had been nothing else against it.
Aids to Reflection|Samuel Taylor Coleridge
For if not, it is merely a petitio principii, and a somewhat wide one.
Arrows of the Chace, v. 2|John Ruskin

Ratione principii, by respect to the principle it proceedeth from.
A Christian Directory (Volume 1 of 4)|Richard Baxter

British Dictionary definitions for petitio principii

petitio principii

/ (pɪˈtɪʃɪˌəʊ prɪnˈkɪpɪˌaɪ) /

noun

logic a form of fallacious reasoning in which the conclusion has been assumed in the premises; begging the questionSometimes shortened to: petitio

Word Origin for petitio principii

C16: Latin, translation of Greek to en arkhei aiteisthai an assumption at the beginning

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012