Voluntários, precisam-se!!

Quem me explica esta, que é verdadeiramente inacreditável?
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“If this sentence is true, then Santa Claus exists.”
We need not believe, beforehand, that the sentence is true or that Santa Claus exists. But we can ask, hypothetically, if the sentence is true, then does Santa Claus exist?

If the sentence is true, then what it says is true, namely that if the sentence is true, then Santa Claus exists. Therefore the answer to the hypothetical question must be yes: Santa Claus does exist if the sentence is true. However, that is exactly what the sentence states: not that Santa Claus exists, but that he exists if the sentence is true, which is what the hypothetical answer just established. Therefore the sentence is true after all, and since we have established that Santa Claus exists if the sentence is true, and that it is true, it follows that Santa Claus must exist.

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Afinal, o Pai Natal sempre existe. Será que ele me cura a dor de cabeça que me deu ler isto?