בשני בתים

in two separate houses, and consequently the two outer courtyards do not join together and become as one.

כמאן כבית שמאי דתניא חמשה שגבו את עירובן ונתנוהו בשני כלים בית שמאי אומרים אין עירובן עירוב ובית הלל אומרים עירובן עירוב

The Gemara asks: In accordance with whose opinion did Rav Sheshet state that an eiruv placed in two houses, even within the same courtyard, does not join the houses together? He must have said this in accordance with the opinion of Beit Shammai, as it was taught in a baraita:

With regard to five people who collected their eiruv and placed it in two separate utensils, even in a single house, Beit Shammai say: Their eiruv is not a valid eiruv, as the two parts of the eiruv have not been deposited in the same place, and Beit Hillel say: Their eiruv is a valid eiruv as long as the entire eiruv was deposited in a single domain.

אפילו תימא בית הלל עד כאן לא קאמרי בית הלל התם אלא בשני כלים בבית אחד אבל בשני בתים לא

The Gemara rejects this argument: Even if you say that this is in accordance with the opinion of Beit Hillel, Beit Hillel may have stated their opinion only there, with regard to two utensils that are located in one house and consequently, they join together. However, if the two utensils are located in two separate houses, even Beit Hillel agree that the eiruv is not valid.

אמר ליה רב אחא בריה דרב אויא לרב אשי לרב יהודה קשיא ולרב ששת קשיא לרב יהודה קשיא דאמר כגון שנתנה אמצעית עירובה בזו ועירובה בזו וכיון דעירבה אמצעית בהדי חיצונה הויא ליה חדא וכי הדרה וערבה בהדי אידך שליחותה עבדה

Rav Aḥa, son of Rav Avya, said to Rav Ashi: The explanation of Rav Yehuda is difficult and the explanation of Rav Sheshet is difficult. The explanation of Rav Yehuda is difficult, as he said that it is speaking about a case where the middle courtyard put its first eiruv in the one courtyard and its second eiruv in the other courtyard. However, once the middle courtyard establishes an eiruv with one of the outer ones, they are regarded as one, so that when it later establishes an eiruv with the other outer courtyard, it acts also on behalf of the first outer courtyard, as both of them are treated like a single courtyard.

ולרב ששת קשיא תיהוי כחמשה ששרויין בחצר אחת ושכח אחד מהן ולא עירב דאסרי אהדדי

And the explanation of Rav Sheshet is difficult. Since the two outer courtyards placed their respective eiruvin in the middle courtyard, all are regarded as residents of the middle courtyard. And since each of the outer courtyards placed its eiruv in a different house, the case should be treated like that of five people who lived in the same courtyard, one of whom forgot and did not join the eiruv, where they all prohibit one another to carry in the courtyard. Similarly in this case, all should be prohibited to carry in the middle courtyard, the residents of the middle courtyard as well as the residents of the outer courtyards.

אמר ליה רב אשי לא לרב יהודה קשיא ולא לרב ששת קשיא לרב יהודה לא קשיא כיון דעירבה לה אמצעית בהדי חיצונה ושתים חיצונות בהדי הדדי לא עירבו גליא דעתיה דבהא ניחא ליה ובהא לא ניחא ליה

Rav Ashi said to him: It is not difficult according to the explanation of Rav Yehuda and it is not difficult according to the explanation of Rav Sheshet. It is not difficult according to the explanation of Rav Yehuda, since the residents of the middle courtyard established an eiruv with each of the two outer courtyards, and the residents of the two outer courtyards did not establish an eiruv with one another. The residents of each of the outer courtyards indicated that it desired to join with the middle courtyard, but did not desire to join with the other outer courtyard. Since the residents of the outer courtyards demonstrated that that they did not want to join together and form a common eiruv, they cannot be forced to do so.

ולרב ששת לא קשיא אם אמרו דיורין להקל יאמרו דיורין להחמיר

And it is not difficult according to the explanation of Rav Sheshet. If they said that the people living in the outer courtyards are considered as residents of the middle courtyard as a leniency, so that they should be permitted to carry in the middle courtyard, does this mean that they will say that they are considered residents of the middle courtyard also as a stringency, so that they should be prohibited from carrying in the middle courtyard as if they live there?

אמר רב יהודה אמר רב זו דברי רבי שמעון אבל חכמים אומרים רשות אחת משמשת לשתי רשויות אבל לא שתי רשויות משמשות לרשות אחת

Rav Yehuda said that Rav said: This statement in the mishna, that objects may be carried from either of the outer courtyards into the middle courtyard and also from the middle courtyard into either of the outer courtyards, is the statement of, i. e., in accordance with the opinion of, Rabbi Shimon. But the Rabbis say: One domain serves two domains. That is to say, it is permitted to carry objects from either of the outer courtyards into the inner one, as no prohibition is imposed upon the outer courtyards, given that both established an eiruv with the middle courtyard. But two domains do not serve one domain, meaning that it is prohibited to carry objects from the middle courtyard into either of the two outer courtyards. The utensils of the middle courtyard are drawn after the other two, meaning that were he to bring them into one of the outer courtyards, he would be regarded as having removed them from the other.

כי אמריתה קמיה דשמואל אמר לי

Rav Yehuda relates: When I recited this teaching before Shmuel, he said to me: