petitio principii

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

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.

petitio principii

/ 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

Word History and Origins

Origin of petitio principii¹

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

Word History and Origins

Origin of petitio principii¹

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

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.

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But if, as it would seem, the implication is meant that there are no other entities which can be object to the mind except such "things," then it is a clear petitio principii.

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In other words, omitting his petitio principii and his allusion to the test of fertility, the great criterion in his view is the criterion of Heredity.

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

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The great argument that men are determined by the strongest motives, is a mere equivocation, and what logicians call petitio principii.

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