I have heard of a little alien who claimed to have dreamt about a planet called Earth. In which bipedal creatures have built a huge civilization. The little alien was very sure that his dream was true. The dad alien replied "Extraordinary claims require extraordinary evidence". And they never found earth. It seems the dad's statement was some cultural fad for a retort about any extraordinary 'what if' thinking in that planet. They never progressed in science and died out.

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