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Pigs would fly: Difference between revisions
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==Mainly about== | ==Mainly about== | ||
In conditional sentences<ref>In this context, a statement with an assumption and a conclusion. </ref>, it is a kind of wordplay or rhetoric used in the concluding part to show that an assumption is improbable. | In conditional sentences<ref>In this context, it is a statement with an assumption and a conclusion. </ref>, it is a kind of wordplay or rhetoric used in the concluding part to show that an assumption is improbable. | ||
For example, considering the case that there is a given assumption "[[User:Notorious]] is a genius" and a person says "If [[User:Notorious]] were a genius, pigs would fly", we can see that the person thinks that "[[User:Notorious]] can't be a genius.<ref>But why? He is a genius.</ref> | For example, considering the case that there is a given assumption "[[User:Notorious]] is a genius" and a person says "If [[User:Notorious]] were a genius, pigs would fly", we can see that the person thinks that "[[User:Notorious]] can't be a genius.<ref>But why? He is a genius.</ref> | ||
==The logical consistency of saying it== | ==The logical consistency of saying it== | ||
The problem if there is any consistency in concluding that "pigs fly" when the assumption is impossible (called "''Pigs! Would! Fly!''" Problem) has only recently begun to be pointed out, and since ancient{{Contradiction}} times it has continued to trouble the minds of logicians, philosophers, physicists, mathematicians, or cultists <del>who like to fantasize about things that are totally useless in reality</del>. However, it is now known that this "Pigs! Would! Fly!" Problem can be proven by the {{interlanguage link|Article name=Contrapositive|Lang code=ja|Page=対偶}} argument. | |||
Let an improbable assumption be symbolically "Mn". Now, all we need to do is verify whether the proposition "If Mn, then pigs will fly." is true or not. | |||
To prove that the proposition "If Mn, then pigs fly." is true, we prove that its [[counterpart]] "If pigs do not fly, then not-Mn." is true.<ref>Generally, the truth values of proposition P and its [[counterpart]], proposition Q, are equal.</ref> | |||
For the assumption "Pigs do not fly." of the proposition "If pigs do not fly, then not-Mn," it always stands; in this world, no pig flies. And for the conclusion "Not-Mn," it also always stands; Mn is an improbable assumption, and the world is divided only two, Mn or not-Mn. For this proposition, therefore, as the conclusion always stands when the assumption stands, thus it is true. | |||
Then the proposition "If Mn, pigs would fly." is true, as a proposition, where its {{interlanguage link|Article name=Contrapositive|Lang code=ja|Page=対偶}} is true, is true. | |||
The answer that has a logical consistency to "Pigs! Would! Fly!" Problem can be proved as such. | |||
==Footnote== | ==Footnote== | ||
<references /> | <references /> | ||