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An a fortiori argument is an "argument from a yet stronger reason." (The phrase ''a fortiori'' is Latin for "from () stronger".) An ''a fortiori'' argument draws upon existing confidence in a proposition to argue in favor of a second proposition that is held to be implicit in the first. The second proposition may be considered "weaker," and therefore the arguer adduces a "stronger" proposition to support it. For example, if a person is dead (the stronger reason), then one can with equal or greater certainty argue that the person is not breathing. "Being dead" trumps other arguments that might be made to show that the person is not breathing, such as, for instance, not seeing any sign of breathing. (Provided, of course, that the determination of "being dead" can be made without using "not breathing" as evidence, else this scenario becomes circularly reasoned.) ==Usage== In the English language, the phrase ''a fortiori'' is most often used as an adverbial phrase meaning "by even greater force of logic" or "all the more so". Bryan Garner, an authority on usage, has written in ''Garner's Modern American Usage'' that writers sometimes use ''a fortiori'' as an adjective, which he says is "a usage to be resisted." As an example of this he gives the sentence, "Clearly, if laws depend so heavily on public acquiescence, the case of conventions is an ''a fortiori'' (''even more compelling'' ) one." ''A fortiori'' arguments are regularly used in Jewish Law under the name kal va-chomer (Light and Heavy). In ancient Indian logic (nyaya), an ''a fortiori'' inference is known as ''kaimutika'' or ''kaimutya nyaya'', from the words ''kim uta'' meaning "even more so." In Islamic jurisprudence, ''a fortiori'' arguments are among the methods used in ''qiyas'' (reasoning by analogy). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「A fortiori argument」の詳細全文を読む スポンサード リンク
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