What’s the difference between halakha (הֲלָכָה), custom (מִנְהָג) and the people were accustomed to act (נָהֲגוּ הָעָם )? TB Eruvin 72

The discussion about the erev hatzerot (חצרות ערוב) and the shituf mvui (שיתוף מבוי), the technical term for the unification of an alleyway for the purposes of carrying from a courtyard to the alleyway and back, on TB Eruvin 71b flows onto today’s daf TB Eruvin 72. May a shituf mvui serve double duty, not only unifying the alleyway but also unifying the adjoining courtyards and the houses to a particular courtyard? The Gemara always frames Rabbi Meir’s position as the more stringent one and the sages’ position as the more lenient one. Depending on which of the two lenses the argument is viewed, Rabbi Meir either holds the position that one must always have to separate unification’s, an erev hatzerot and a shituf mvui or one only needs to separate unification’s when the foodstuff isn’t bread. The sages always hold no matter what is used to unify the alleyway can serve double duty and unify the courtyards.

This matter is concluded with “אָמַר רַב יְהוּדָה אָמַר רַב: הֲלָכָה כְּרַבִּי מֵאִיר. וְרַב הוּנָא אָמַר: מִנְהָג כְּרַבִּי מֵאִיר. וְרַבִּי   יוֹחָנָן אָמַר:  הָעָם כְּרַבִּי מֵאִיר.נָהֲגוּ -Rav Yehuda said that Rav said: The halakha is in accordance with the opinion of Rabbi Meir. And Rav Huna said: custom is in accordance with the opinion of Rabbi Meir. And Rabbi Yoḥanan said: the people were accustomed to act in accordance with the opinion of Rabbi Meir.” Sefaria.org translation)

What’s the difference between halakha (הֲלָכָה), custom (מִנְהָג) and “the people were accustomed to act” (נָהֲגוּ )? Rashi answers my question by summarizing the Gemara TB Ta’anit 26b. There the issue is during which services may a kohen dukhin, blessing the congregation with the priestly benediction. I’ll share with you the actual source. “The Gemara clarifies these statements. The one who said that the halakha is in accordance with the opinion of Rabbi Meir means that this ruling is taught in the public lectures on Shabbat. The one who said that the custom is in accordance with the opinion of Rabbi Meir means that one does not teach this in public, but if someone comes to ask for a practical ruling, one instructs them in private that this is the halakha. And the one who said that the people act in accordance with the opinion of Rabbi Meir means that one does not even instruct someone that this is the halakha, but if he acts in accordance with Rabbi Meir, he has acted in a valid manner and we do not require him to return and recite the prayer again.” (Ta’anit 26b, Sefaria.org translation)

 A halakha (הֲלָכָה) is a society norm; consequently, it is taught publicly. Because the issue revolving around the custom (מִנְהָג) is not clear to the sages, they don’t teach it publicly. The custom (מִנְהָג) indicates that this approach is most likely acceptable; consequently, when asked, the individual is instructed in private.  “The people act in accordance” (נָהֲגוּ הָעָם) means that the sages don’t get involved and allow the community decide how to behave.

 

Today we allow the shituf mvui (שיתוף מבוי) to do double duty and unify not only the alleyway, but also the courtyard. A rabbi as the agent for the community will set aside a box of matza (because it stays fresher much longer any loaf of bread) and that will unify all the enclosed area’s streets and houses. This position could either be one of Meir’s position as explained above or according to the sages as understood by Rabbi Yoḥanan. (See: Shulkhan Arukh, Orekh Hayyim, 387, explicitly the Rama)