adj.

逆説的な、奇異性の、奇異な

関: bizarre、paradoxic、paradoxically

WordNet

seemingly contradictory but nonetheless possibly true; "it is paradoxical that standing is more tiring than walking" (同)self-contradictory
conspicuously or grossly unconventional or unusual; "restaurants of bizarre design--one like a hat, another like a rabbit"; "famed for his eccentric spelling"; "a freakish combination of styles"; "his off-the-wall antics"; "the outlandish clothes of teenagers"; "outre and affected stage antics" (同)eccentric, freakish, freaky, flaky, flakey, gonzo, off-the-wall, outlandish, outre
in a paradoxical manner; "paradoxically, ice ages seem to occur when the sun gets hotter"

PrepTutorEJDIC

逆説の;逆説を好む / 矛盾する
一風変わった,変な(odd);奇怪な,異様な(grotesque)

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/02/22 19:45:48」(JST)

wiki en

[Wiki en表示]

For other uses, see Paradox (disambiguation).

A paradox is a statement that apparently contradicts itself and yet might be true.^[1]^[2] Most logical paradoxes are known to be invalid arguments but are still valuable in promoting critical thinking.^[3]

Some paradoxes have revealed errors in definitions assumed to be rigorous, and have caused axioms of mathematics and logic to be re-examined. One example is Russell's paradox, which questions whether a "list of all lists that do not contain themselves" would include itself, and showed that naive set theory was flawed.^[4] Others, such as Curry's paradox, are not yet resolved.

Examples outside logic include the Ship of Theseus from philosophy (questioning whether a ship repaired over time by replacing each its wooden parts would remain the same ship). Paradoxes can also take the form of images or other media. For example, M.C. Escher featured perspective-based paradoxes in many of his drawings, with walls that are regarded as floors from other points of view, and staircases that appear to climb endlessly.^[5]

In common usage, the word "paradox" often refers to statements that are ironic or unexpected, such as "the paradox that standing is more tiring than walking".^[2]

Logical paradox[edit]

See also: List of paradoxes

Common themes in paradoxes include self-reference, infinite regress, circular definitions, and confusion between different levels of abstraction.

Patrick Hughes outlines three laws of the paradox:^[6]

Self-reference

An example is "This statement is false", a form of the liar paradox. The statement is referring to itself. Another example of self-reference is the question of whether the barber shaves himself in the barber paradox. One more example would be "Is the answer to this question 'No'?"

Contradiction

"This statement is false"; the statement cannot be false and true at the same time.

Vicious circularity, or infinite regress

"This statement is false"; if the statement is true, then the statement is false, thereby making the statement true. Another example of vicious circularity is the following group of statements:

"The following sentence is true."

"The previous sentence is false."

"What happens when Pinocchio says, 'My nose will grow now'?"

Other paradoxes involve false statements ("impossible is not a word in my dictionary", a simple paradox) or half-truths and the resulting biased assumptions. This form is common in howlers.

For example, consider a situation in which a father and his son are driving down the road. The car crashes into a tree and the father is killed. The boy is rushed to the nearest hospital where he is prepared for emergency surgery. On entering the surgery suite, the surgeon says, "I can't operate on this boy. He's my son."

The apparent paradox is caused by a hasty generalization, for if the surgeon is the boy's father, the statement cannot be true. The paradox is resolved if it is revealed that the surgeon is a woman — the boy's mother.

Paradoxes which are not based on a hidden error generally occur at the fringes of context or language, and require extending the context or language in order to lose their paradoxical quality. Paradoxes that arise from apparently intelligible uses of language are often of interest to logicians and philosophers. "This sentence is false" is an example of the well-known liar paradox: it is a sentence which cannot be consistently interpreted as either true or false, because if it is known to be false, then it is known that it must be true, and if it is known to be true, then it is known that it must be false. Therefore, it can be concluded that it is unknowable. Russell's paradox, which shows that the notion of the set of all those sets that do not contain themselves leads to a contradiction, was instrumental in the development of modern logic and set theory.

Thought experiments can also yield interesting paradoxes. The grandfather paradox, for example, would arise if a time traveller were to kill his own grandfather before his mother or father had been conceived, thereby preventing his own birth. This is a specific example of the more general observation of the butterfly effect, or that a time-traveller's interaction with the past — however slight — would entail making changes that would, in turn, change the future in which the time-travel was yet to occur, and would thus change the circumstances of the time-travel itself.

Often a seemingly paradoxical conclusion arises from an inconsistent or inherently contradictory definition of the initial premise. In the case of that apparent paradox of a time traveler killing his own grandfather it is the inconsistency of defining the past to which he returns as being somehow different from the one which leads up to the future from which he begins his trip but also insisting that he must have come to that past from the same future as the one that it leads up to.

Quine's classification of paradoxes[edit]

W. V. Quine (1962) distinguished between three classes of paradoxes:

A veridical paradox produces a result that appears absurd but is demonstrated to be true nevertheless. Thus, the paradox of Frederic's birthday in The Pirates of Penzance establishes the surprising fact that a twenty-one-year-old would have had only five birthdays, if he had been born on a leap day. Likewise, Arrow's impossibility theorem demonstrates difficulties in mapping voting results to the will of the people. The Monty Hall paradox demonstrates that a decision which has an intuitive 50-50 chance in fact is heavily biased towards making a decision which, given the intuitive conclusion, the player would be unlikely to make. In 20th century science, Hilbert's paradox of the Grand Hotel and Schrödinger's cat are famously vivid examples of a theory being taken to a logical but paradoxical end.
A falsidical paradox establishes a result that not only appears false but actually is false, due to a fallacy in the demonstration. The various invalid mathematical proofs (e.g., that 1 = 2) are classic examples, generally relying on a hidden division by zero. Another example is the inductive form of the horse paradox, which falsely generalizes from true specific statements.
A paradox that is in neither class may be an antinomy, which reaches a self-contradictory result by properly applying accepted ways of reasoning. For example, the Grelling–Nelson paradox points out genuine problems in our understanding of the ideas of truth and description.

A fourth kind has sometimes been described since Quine's work.

A paradox that is both true and false at the same time and in the same sense is called a dialetheia. In Western logics it is often assumed, following Aristotle, that no dialetheia exist, but they are sometimes accepted in Eastern traditions^[which?] and in paraconsistent logics. It would be mere equivocation or a matter of degree, for example, to both affirm and deny that "John is here" when John is halfway through the door but it is self-contradictory to simultaneously affirm and deny the event in some sense.

Paradox in philosophy[edit]

A taste for paradox is central to the philosophies of Laozi, Heraclitus, Meister Eckhart, Hegel, Kierkegaard, Nietzsche, and G.K. Chesterton, among many others. Søren Kierkegaard, for example, writes, in the Philosophical Fragments, that

But one must not think ill of the paradox, for the paradox is the passion of thought, and the thinker without the paradox is like the lover without passion: a mediocre fellow. But the ultimate potentiation of every passion is always to will its own downfall, and so it is also the ultimate passion of the understanding to will the collision, although in one way or another the collision must become its downfall. This, then, is the ultimate paradox of thought: to want to discover something that thought itself cannot think.^[7]

References[edit]

^ "Paradox". Merriam-Webster. Retrieved 2013-08-30.
^ ^a ^b "Paradox". Free Online Dictionary, Thesaurus and Encyclopedia. Retrieved 2013-01-22.
^ Eliason, James L. (March–April 1996). "Using Paradoxes to Teach Critical Thinking in Science". Journal of College Science Teaching 15 (5): 341–44. (subscription required (help)).
^ LaFleur, Kelly (July 2011). "Russell's Paradox" (pdf). Center for Science, Mathematics & Computer Education (Thesis). University of Nebraska-Lincoln.
^ Skomorowska, Amira (ed.). "The Mathematical Art of M.C. Escher". Lapidarium notes. Retrieved 2013-01-22.
^ Hughes, Patrick; Brecht, George (1975). Vicious Circles and Infinity - A Panoply of Paradoxes. Garden City, New York: Doubleday. pp. 1–8. ISBN 0-385-09917-7. LCCN 74-17611.
^ Kierkegaard, Søren (1985). Hong, Howard V.; Hong, Edna H., eds. Philosophical Fragments. Princeton University Press. p. 37. ISBN 9780691020365.

External links[edit]

Wikiquote has a collection of quotations related to: Paradox

Look up paradox in Wiktionary, the free dictionary.

Wikimedia Commons has media related to Paradoxes.

Cantini, Andrea (Winter 2012). "Paradoxes and Contemporary Logic". In Zalta, Edward N. Stanford Encyclopedia of Philosophy.
Spade, Paul Vincent (Fall 2013). "Insolubles". In Zalta, Edward N. Stanford Encyclopedia of Philosophy.
Paradoxes on the Open Directory Project
"Zeno and the Paradox of Motion" at MathPages.com.

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 成人における心房中隔異常（PFO、ASD、およびASA）および脳塞栓症のリスク atrial septal abnormalities pfo asd and asa and risk of cerebral emboli in adults
2. 声帯ひだ奇異性運動 paradoxical vocal fold motion
3. 成人における心房中隔欠損症の閉鎖適応および医療マネージメント indications for closure and medical management of atrial septal defects in adults
4. 小児における喘息以外の喘鳴疾患 wheezing illnesses other than asthma in children
5. 成人における心房中隔欠損症の臨床症状および診断 clinical manifestations and diagnosis of atrial septal defects in adults

English Journal

Sleep architecture and homeostasis in mice with partial ablation of melanin-concentrating hormone neurons.

Varin C1, Arthaud S1, Salvert D1, Gay N1, Libourel PA1, Luppi PH1, Léger L1, Fort P2.
Behavioural brain research.Behav Brain Res.2016 Feb 1;298(Pt B):100-10. doi: 10.1016/j.bbr.2015.10.051. Epub 2015 Oct 31.
Recent reports support a key role of tuberal hypothalamic neurons secreting melanin concentrating-hormone (MCH) in the promotion of Paradoxical Sleep (PS). Controversies remain concerning their concomitant involvement in Slow-Wave Sleep (SWS). We studied the effects of their selective loss achieved
PMID 26529469

The immunopathogenesis of cryptococcal immune reconstitution inflammatory syndrome: understanding a conundrum.

Meya DB1, Manabe YC, Boulware DR, Janoff EN.
Current opinion in infectious diseases.Curr Opin Infect Dis.2016 Feb;29(1):10-22. doi: 10.1097/QCO.0000000000000224.
PURPOSE OF REVIEW: Cryptococcal meningitis causes significant mortality among HIV-infected patients, despite antifungal therapy and use of antiretroviral therapy (ART). In patients with cryptococcal meningitis, ART is often complicated by immune reconstitution inflammatory syndrome (IRIS), manifesti
PMID 26658650

Radiotelemetry and wildlife: Highlighting a gap in the knowledge on radiofrequency radiation effects.

Balmori A1.
The Science of the total environment.Sci Total Environ.2016 Feb 1;543(Pt A):662-9. doi: 10.1016/j.scitotenv.2015.11.073. Epub 2015 Nov 23.
Radio transmitters and associated devices may induce negative effects that can bias the results of ongoing research. The main documented effects of radio transmitters on animals include reduced survival, decreased productivity, changes in behaviour and movement patterns and a biased sex ratio. The o
PMID 26615484

A Paradoxical Treatment for a Paradoxical Condition: Infliximab Use in Three Cases of Mycobacterial IRIS.

Hsu DC1, Faldetta KF1, Pei L1, Sheikh V1, Utay NS2, Roby G1, Rupert A3, Fauci AS1, Sereti I1.
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America.Clin Infect Dis.2016 Jan 15;62(2):258-61. doi: 10.1093/cid/civ841. Epub 2015 Sep 22.
The management of corticosteroid refractory immune reconstitution inflammatory syndrome (IRIS) is currently unclear. Infliximab administration was associated with clinical improvement without significant adverse events in 3 patients with mycobacterial IRIS. Immunologic and virologic responses to ant
PMID 26394669

Japanese Journal

A system of pair sentential calculus that has a representation of the Liar sentence

石井忠夫
新潟国際情報大学情報文化学部紀要 1, 1-10, 2015-04-01
… We also introduce a referential cycle number of (Ai,Bj) and by using of this cycle number, we may classify pair-sentences into two categories, that is, categorical and paradoxical. … Then each Liar sentence has a referential cycle number of n such that n 2 and is paradoxical. …
NAID 120005594457

研究・症例オスラー病(遺伝性出血性末梢血管拡張症)からみた肺動静脈奇形

塩谷隆信,佐竹將宏,奥田祐道 [他]
日本胸部臨床 74(4), 454-462, 2015-04
NAID 40020423431

パーキンソン病の姿勢反射障害,すくみ足に対するクロスオーバーデザイン・矛盾性運動を利用した反復ステップ運動の効果

梅原圭二,高橋光彦
理学療法ジャーナル 49(4), 365-373, 2015-04
NAID 40020409939

<一般論文>真理概念は論理結合子となりうるか―真理理論とハーモニー―

矢田部俊介
科学哲学科学史研究 (9), 2015-03-31
… Such ω-inconsistencyis caused by the fact that the truth predicate enables us to define paradoxical formulaeof seemingly infinite-length. … The reason of the failure of the harmony isthat these criteria are defined not for coinductively defined paradoxical formulae butfor inductively defined formulae. …
NAID 120005593663

Related Pictures

★リンクテーブル★

リンク元	「逆説的」「奇異」「paradoxically」「奇異性」「bizarre」
拡張検索	「interventricular septal paradoxical motion」「paradoxical septal motion」
関連記事	「paradoxic」

「逆説的」

　　[★]

英: paradoxical、paradoxic、paradoxically
関: 奇異、奇異性

「奇異」

　　[★]

英: bizarre、paradoxical, bizarreness
関: 奇異性、逆説的

「paradoxically」

　　[★]

逆説的に

関: paradoxic、paradoxical

「奇異性」

　　[★]

英: paradoxical
関: 奇異、逆説的

「bizarre」

　　[★]

奇異な

関: paradoxical

「interventricular septal paradoxical motion」

　　[★] 心室中隔奇異性運動

「paradoxical septal motion」