petitio principii

American  

[pi-tish-ee-oh prin-sip-ee-ahy, pe-tee-ti-oh pring-kip-i-ee] / pɪˈtɪʃ iˌoʊ prɪnˈsɪp iˌaɪ, pɛˈti tɪˌoʊ prɪŋˈkɪp ɪˌi /

noun

Logic.

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

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petitio principii British  

/ pɪˈtɪʃɪˌəʊ prɪnˈkɪpɪˌaɪ /

noun

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

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Etymology

Origin of petitio principii

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

Example Sentences

And it is as much a petitio principii to assume, in Ethics, the existence of moral feelings, as to assume, in Optics, the existence of sight.

From A Review of the Systems of Ethics Founded on the Theory of Evolution by Williams, C. M.

This mode of reasoning, by which a bad generalization is made to overrule all facts which contradict it, is petitio principii in one of its most palpable forms.

From A System of Logic: Ratiocinative and Inductive 7th Edition, Vol. II by Mill, John Stuart

Is it not then a petitio principii to say, that the fact ought to be disbelieved because the induction opposed to it is complete?

From A System of Logic: Ratiocinative and Inductive 7th Edition, Vol. II by Mill, John Stuart

It may be represented, also, as a petitio principii, or reasoning in a circle,—since the proof that the will is determined by the strongest motive is no other than the fact that it is determined.

From A Review of Edwards's by Tappan, Henry Philip

Mr. Mill decides that the proposition is not a petitio principii; Dr. Farrar says, as in continuation of his reference to Mr. Mill, that it is a flagrant petitio principii.

From Supernatural Religion, Vol. I. (of III) An Inquiry into the Reality of Divine Revelation by Cassels, Walter Richard