I am not an orthodox Jew but I do like to investigate the truth of things in religions.
I was always wondering how the Manhattan eruv was a “valid” one by orthodox Judaism since a street like Broadway — or really any street — is a dirshus haRabbim which can hold over 600,000 people at once (and perhaps does once a year, also counting the subway).
An eruv originally was supposed to unite “private” domains into one super-domain. The tradition holds that it was instituted by King Solomon himself, to unite Jews who otherwise would not be able to carry things to their neighbors.
So I checked — and it turns out that the rabbinate which oversees it is actually not orthodox, but reconstructionist or something. It is based on Monsey, which is home to many orthodox Jews, so hearing that the eruv is overseen by Monsey sounds like it’s orthodox.
I don’t know any orthodox Jews who use it. And eruvin are basically used by orthodox Jews.
(Fun fact: it doesn’t go through Moshe Feinstein’s old neighborhood, Chelsea, where I used to live, because he opposed it. Another rabbi who opposed any eruvin — even kosher ones — was Menachem Shneerson of Chabad. So in crown heights there is an “eruv dispute” between the orthodox, who use it when they eg walk strollers with their children on Shabbat, and the ultra-orthodox, who refuse to use it and post signs that it’s not to be used: https://forward.com/news/345405/brooklyn-eruv-feud-spreads-t... ).
I think this is an interesting topic for Hacker News because the people here often investigate rules and reasons for them, and this whole topic — even the Talmud eruv rules themselves — is about rules and hacking in a way.