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 Project Gutenberg

Besides, the author, in this assertion, is guilty of a most glaring petitio principii.

From Project Gutenberg

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.

From Project Gutenberg

Such an argument is no argument at all; it is a mere petitio principii, incapable of proving anything.

From Project Gutenberg

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

From Project Gutenberg