והוינן בה מ"ש לכאן ולכאן דלא דאין ברירה מזרח ומערב נמי אין ברירה
And we discussed the following difficulty with regard to this teaching of Ayo: What is different about the case where two rabbis are coming to the two locations, one here and the other there, and one places two eiruvin, planning to decide on Shabbat which lecture he will attend? Why did Rabbi Yehuda state that this may not be done? It is because he held that there is no retroactive designation. But if so, in the first case as well, where only one rabbi comes, but the location of his lecture was not known before Shabbat, and one placed eiruvin in the east and the west, we should say that neither is effective because the rabbi’s location will not be known until Shabbat, and there is no retroactive designation.
וא"ר יוחנן וכבר בא חכם אלמא לית ליה לר' יוחנן ברירה
And Rabbi Yoḥanan said in explanation: This first case is referring to a situation in which the rabbi had already arrived before the eiruv was placed, but the one placing the eiruv does not know the rabbi’s location. Therefore, it had already been determined which of the two eiruvin would be effective, although it was not yet known to him when Shabbat began. Apparently, then, Rabbi Yoḥanan does not accept the principle of retroactive designation even in matters of rabbinic law, as he states that if the rabbi were to arrive after the eiruv was placed, it would not be effective retroactively.
אלא לעולם לא תיפוך וכי לית ליה לרבי אושעיא ברירה בדאורייתא אבל בדרבנן אית ליה
Rather, the Gemara rejects this approach and states: Actually, do not reverse the views of Rabbi Yoḥanan and Rabbi Hoshaya; it is indeed Rabbi Hoshaya, also known as Rabbi Oshaya, who accepts retroactive designation, and Rabbi Yoḥanan who rejects it. As for Rabbi Oshaya’s statement with regard to the entrances to a house that contains a corpse, the following answer may be offered: And when does Rabbi Oshaya not hold of the principle of retroactive designation? With regard to matters of Torah law, such as the ritual impurity of the dead. But with regard to matters of rabbinic law, such as Shabbat limits and the placement of eiruvin, he does accept this principle.
דרש מר זוטרא הלכה כרבי אושעיא
Mar Zutra taught in a public lesson: The halakha is in accordance with the opinion of Rabbi Oshaya with regard to retroactive designation.
אמר שמואל שור של פטם הרי הוא כרגלי כל אדם שור של רועה הרי הוא כרגלי אותה העיר:
Shmuel said: An ox of a fattener, one whose occupation is to fatten oxen in order to sell them for their meat, is as the feet of all people. It is as the feet of the one who acquires the animal on the Festival, even if the buyer is from another city, as the fattener’s intention when the Festival begins is that the ox belong to whoever buys it. But an ox of a shepherd, who raises oxen for himself but occasionally sells them to his neighbors or acquaintances, is as the feet of the people of that city, as his intention when the Festival begins is that he might sell the animal to someone in town, but not to someone from out of town.
השואל כלי מחבירו מערב יו"ט: פשיטא לא צריכא שלא מסרו לו אלא ביו"ט מהו דתימא לאו ברשותיה אוקמיה קמ"ל
§ The mishna states: In the case of one who borrows a vessel from another on the eve of a Festival, it is as the feet of the borrower. The Gemara asks: It is obvious that this is the case, as the place of rest of the vessel has already been established in the possession of the borrower. The Gemara answers: No, it is necessary to state this halakha in a case where one did not deliver the vessel to him until the Festival itself. Lest you say: Since the lender did not establish it in the borrower’s possession before the Festival began, it should remain as the feet of the lender, the mishna therefore teaches us that it is not so, but it is as the feet of the borrower.
מסייע ליה לר' יוחנן דא"ר יוחנן השואל כלי מחבירו מערב יום טוב אף על פי שלא נתנו לו אלא ביו"ט הרי הוא כרגלי השואל:
The Gemara comments: Interpreted in this manner, the mishna supports a statement of Rabbi Yoḥanan, as Rabbi Yoḥanan said: One who borrows a vessel from another on the eve of a Festival, even if he did not give it to him until the Festival itself, it is as the feet of the borrower.
ביו"ט כרגלי המשאיל: פשיטא לא צריכא דרגיל ושאיל מיניה מהו דתימא ברשותיה קא מוקים ליה קמ"ל מימר אמר דלמא משכח איניש אחרינא ואזיל ושאיל מיניה:
§ It is taught in the mishna: If one borrowed on the Festival itself, it is as the feet of the lender. The Gemara again wonders: This is obvious. The Gemara answers: No, it is necessary to state this halakha in a case where this borrower is accustomed to borrowing such items from this lender. Lest you say that since it is a regular occurrence for this loan to take place, the lender establishes it in his possession ahead of time, and it should therefore be considered as though the object’s place of rest is established as the feet of the borrower, the mishna therefore teaches us that it is not so, as the lender certainly says to himself: Perhaps he will find someone else this time, and he will go and borrow from him. Consequently, the lender does not transfer possession of the object to the borrower until the latter takes it, and it may be carried only where the lender may go.
וכן האשה ששאלה מחברתה: כי סליק רבי אבא אמר יהא רעוא דאימא מלתא דתתקבל כי סליק אשכחיה לר' יוחנן ורבי חנינא בר פפי ור' זירא ואמרי לה ר' אבהו ור' שמעון בן פזי ור' יצחק נפחא ויתבי וקאמרי אמאי ולבטיל מים ומלח לגבי עיסה אמר להו ר' אבא
§ It is taught in the mishna: And similarly, a woman who borrowed spices from another to put in a dish, or water and salt to put in her dough, these are as the feet of both of them. The Gemara relates: When Rabbi Abba ascended from Babylonia to Eretz Yisrael, he said: May it be God’s will that I say a statement of halakha that will be accepted by my listeners in Eretz Yisrael, so that I will not be put to shame. When he ascended, he found Rabbi Yoḥanan, Rabbi Ḥanina bar Pappi, and Rabbi Zeira, and some say he found Rabbi Abbahu, Rabbi Shimon ben Pazi, and Rabbi Yitzḥak Nappaḥa, and they were sitting and saying in a discussion of the mishna: Why is this the halakha with regard to dough? But let the water and salt be considered nullified in the dough, and the status of the dough should follow its flour rather than its minor ingredients, such as water and salt. Rabbi Abba said to them: