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This article is about a reasoning technique in Umineko When They Cry. |
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"All ravens are black" because all confirmed birds are non-black
A simplification used by Ronove. If we know the cookie is in either box, and it's not in Box A, we can claim it's in Box B without checking.
Hempel's Raven (ヘンペルのカラス Henperu no Karasu), based on the raven paradox, was proposed to illustrate a contradiction between inductive and deductive logic.
Premise: All ravens are black.
Material Implication: Anything non-black is not a raven.
Lacking a raven to observe, the entire observable set of non-black objects can be taken as evidence of the raven's blackness.
Even its most accepting critics are doubtful of the quality of proof that can be derived from this, but it can be used to further undermine already weak arguments.
A practical example used by Beatrice can be summarized as this: "From all observed non-ravens, none have been black. Meaning, black birds, if exist, can only be ravens." Alternatively, "From all non-black birds, none were a raven. Meaning, ravens, if exist, can only be non-black." would mean the same. This assumes we can reliably collect the entire group we make a claim for.
In the game with Battler, it's used to demonstrate that instead of using Red Truth to disprove a Devil's Proof directly, it can be used to validate a counterargument for the same effect, thus creating more options for a counterattack.
Uses of Hempel's Raven[]
Banquet of the Golden Witch[]
- Ronove and Beatrice explain the concept with the abovementioned "raven" example.
- Battler makes a Devil's Proof argument "the 19th person is the culprit, therefore, the 18 are innocent, and the witch doesn't exist", to avoid treating the people he's aware of as suspects. Beatrice counters with "therefore, if I can prove that the culprit is not some 19th person, we can be sure that the culprit is either one of the 18 or a witch". This also aligns with the first rule of Knox's Decalogue.
- Ronove and Beatrice give as an example that a theory of "all humans except me are foolish" can be changed into "I am wise and therefore all humans except me are foolish".
- Ronove gives an example that "the blessed are the servants of a god" is used in some religions to imply that those who are not servants of a god are not blessed.
- EVA-Beatrice states that the contradictory Red Truth regarding Kyrie's thought process implies the use of supernatural brainwashing. Beatrice resolves the paradox by arguing that Kyrie had a different goal for leaving the guesthouse, independent of her reasoning.
End of the Golden Witch[]
- Everyone but Natsuhi and Krauss have confirmed alibis. Since Natsuhi claims Krauss is innocent, she risks being declared guilty despite there being no evidence she has committed the crime.
- Kinzo's location is proven to be not in any location other than Natsuhi's room. Since Natsuhi claims he's still alive, it's interpreted as her claiming he's been in her room during the night.
Dawn of the Golden Witch[]
- Because Erika's tape guarantees a sealed room is a Closed Room, Gaap tries to argue that in order for a human to escape, it has to mean at the time the room hasn't been sealed completely.
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