argumentum ad absurdum
From LSJ
τὸ ἐγδοχῖον τοῦ ὕδατος καὶ τὰ ἐν τῆι πόλει ὑδραγώγια → the water reservoir and the conduits in the city (or on the acropolis)
Wikipedia EN
In logic, reductio ad absurdum (Latin for "reduction to absurdity"), also known as argumentum ad absurdum (Latin for "argument to absurdity") or apagogical arguments, is the form of argument that attempts to establish a claim by showing that the opposite scenario would lead to absurdity or contradiction. This argument form traces back to Ancient Greek philosophy and has been used throughout history in both formal mathematical and philosophical reasoning, as well as in debate.