When a person “disappears” into water, can we assume that he drowned, or must we consider the possibility that he survived and perhaps is alive, even though we cannot find him?
The Mishna on our daf suggests that we need to distinguish between different types of bodies of water. When dealing with mayim she-ein lahem sof – literally “water with no end,” i.e., a large body of water whose end cannot be seen – we must be concerned that he survived, while regarding mayim she-yesh lahem sof – when we can see the entire body of water – we can assume that he died. Rabbi Meir does not distinguish between the two, arguing that even in mayim she-yesh lahem sof we must operate with the assumption that the person could survive. To support his position, Rabbi Meir tells of a man who fell into ha-bor ha-gadol – the Great Cistern – and came out alive three days later. The baraita quotes the retort of the other Sages to Rabbi Meir – “we do not accept proofs from miraculous occurrences.”
It appears that “the Great Cistern” referred to was one with which the Sages were familiar. In the continuation of the Gemara a baraita is brought that tells the story of Nehunya Hofer Shihin’s daughter who fell into “the Great Cistern.” When the report reached Rabbi Hanina ben Dosa, he reported that all was well, and after a time that she had been saved. When questioned about it, Rabbi Hanina ben Dosa said that throughout the ordeal he was certain that Nehunya Hofer Shihin’s daughter was safe because she would not be punished with the very object that her father devoted his life to.
According to the Mishna in Shekalim (5:1) Nehunya Hofer Shihin – whose name literally means “Nehunya the well digger” was one of the appointed workers in the Temple, whose official position was to be responsible for water for Jerusalem generally, and specifically for the pilgrims coming to the Temple during the holidays. The Gemara tells that Nehunya was an expert in choosing the correct place to dig wells, thus he was able to fill cisterns not only from the collection of rainwater, but from underground reservoirs, as well.