Rav Pappa said a different explanation for the fact that Rabbi Yehoshua ben Levi made both statements: It was necessary for Rabbi Yehoshua ben Levi to inform us that the halakha is in accordance with the opinion of Rabbi Yoḥanan ben Nuri, because had he said only that the halakha follows the lenient opinion with regard to an eiruv, it could have entered your mind to say that this statement applies only with regard to the laws governing the eiruv of courtyards, which are entirely rabbinic in origin. But with regard to the more stringent laws governing the eiruv of Shabbat limits, you would have said that we should not rule leniently, and therefore it was necessary to make both statements.

The Gemara asks: And from where do you say that we distinguish between an eiruv of courtyards and an eiruv of Shabbat limits? As we learned in a mishna that Rabbi Yehuda said: In what case is this statement said, that an eiruv may be established for another person only with his knowledge? It was said with regard to an eiruv of Shabbat limits, but with regard to an eiruv of courtyards, an eiruv may be established for another person whether with his knowledge or without his knowledge, as one may act in a person’s interest in his absence; however, one may not act to a person’s disadvantage in his absence. One may act unilaterally on someone else’s behalf when the action is to that other person’s benefit; however, when it is to the other person’s detriment, or when there are both advantages and disadvantages to him, one may act on the other person’s behalf only if one has been explicitly appointed as an agent. Since an eiruv of courtyards is always to a person’s benefit, it can be established even without his knowledge. However, with regard to an eiruv of Shabbat limits, while it enables one to walk in one direction, it disallows him from walking in the opposite direction. Therefore, it can be established only with his knowledge.

Rav Ashi said that Rabbi Yehoshua ben Levi’s need to issue two rulings can be explained in another manner: It is necessary for Rabbi Yehoshua ben Levi to inform us that the halakha is in accordance with the opinion of Rabbi Yoḥanan ben Nuri, as if he had said only that the halakha is in accordance with the lenient opinion with regard to an eiruv, it could have entered your mind to say that this statement applies only with regard to the remnants of an eiruv, i.e., an eiruv that had been properly established, where the concern is that it might subsequently have become invalid. But with regard to an initial eiruv, i.e., an eiruv that is just being established and has not yet taken effect, you might have said that we should not rule leniently, and therefore it was necessary to issue both rulings.

The Gemara asks: And from where do you say that we distinguish between the remnants of an eiruv and an initial eiruv? As we learned in a mishna: Rabbi Yosei said: In what case is this statement said, that the Sages stipulated that a fixed quantity of food is necessary for establishing an eiruv? It is said with regard to an initial eiruv, i.e., when setting up an eiruv for the first time; however, with regard to the remnants of an eiruv, i.e., on a subsequent Shabbat when the measure may have become diminished, even a minimal amount suffices.

And they said to establish an eiruv for courtyards only after all the inhabitants of the city merge their alleyways and become like the inhabitants of a single courtyard, so that the law of eiruv should not be forgotten by the children, who may not be aware of the arrangement that has been made with regard to the alleyways.

Since the Gemara discussed the principles cited with regard to halakhic decision-making, it cites additional principles. Rabbi Ya’akov and Rabbi Zerika said: The halakha is in accordance with the opinion of Rabbi Akiva in disputes with any individual Sage, and the halakha is in accordance with the opinion of Rabbi Yosei even in disputes with other Sages, and the halakha is in accordance with the opinion of Rabbi Yehuda HaNasi in disputes with any individual Sage.

The Gemara asks: With regard to what halakha do these principles apply, meaning, to what degree are they binding? Rabbi Asi said: This is considered binding halakha. And Rabbi Ḥiyya bar Abba said: One is inclined toward such a ruling in cases where an individual asks, but does not issue it as a public ruling in all cases. And Rabbi Yosei, son of Rabbi Ḥanina, said: It appears that one should rule this way, but it is not an established halakha that is considered binding with regard to issuing rulings.

Rabbi Ya’akov bar Idi said that Rabbi Yoḥanan said: In the case of a dispute between Rabbi Meir and Rabbi Yehuda, the halakha is in accordance with the opinion of Rabbi Yehuda; in the case of a dispute between Rabbi Yehuda and Rabbi Yosei, the halakha is in accordance with the opinion of Rabbi Yosei; and, needless to say, in the case of a dispute between Rabbi Meir and Rabbi Yosei, the halakha is in accordance with the opinion of Rabbi Yosei. As now, if in disputes with Rabbi Yehuda, the opinion of Rabbi Meir is not accepted as law, need it be stated that in disputes with Rabbi Yosei, Rabbi Meir’s opinion is rejected? Rabbi Yehuda’s opinion is not accepted in disputes with Rabbi Yosei.

Rav Asi said: I also learn based on the same principle that in a dispute between Rabbi Yosei and Rabbi Shimon, the halakha is in accordance with the opinion of Rabbi Yosei. As Rabbi Abba said that Rabbi Yoḥanan said: In cases of dispute between Rabbi Yehuda and Rabbi Shimon, the halakha is in accordance with the opinion of Rabbi Yehuda. Now, if where it is opposed by Rabbi Yehuda the opinion of Rabbi Shimon is not accepted as law, where it is opposed by the opinion of Rabbi Yosei, with whom the halakha is in accordance against Rabbi Yehuda, is it necessary to say that the halakha is in accordance with the opinion of Rabbi Yosei?

The Gemara raises a dilemma: In a dispute between Rabbi Meir and Rabbi Shimon, what is the halakha? No sources were found to resolve this dilemma, and it stands unresolved.

Rav Mesharshiya said: These principles of halakhic decision-making are not to be relied upon. The Gemara asks: From where does Rav Mesharshiya derive this statement?

If you say that he derived it from that which we learned in the mishna that Rabbi Shimon said: To what is this comparable? It is like three courtyards that open into one another, and also open into a public domain. If the two outer courtyards established an eiruv with the middle one, the residents of the middle one are permitted to carry to the two outer ones, and they are permitted to carry to it, but the residents of the two outer courtyards are prohibited to carry from one to the other, as they did not establish an eiruv with one another.

And Rav Ḥama bar Gurya said that Rav said: The halakha is in accordance with the opinion of Rabbi Shimon; and who disagrees with Rabbi Shimon on this matter? It is Rabbi Yehuda. Didn’t you say: In disputes between Rabbi Yehuda and Rabbi Shimon, the halakha is in accordance with the opinion of Rabbi Yehuda? Rather, can we not conclude from this mishna that these principles should not be relied upon?

The Gemara rejects this argument: What is the difficulty posed by this ruling? Perhaps where it is stated explicitly to the contrary, it is stated, but where it is not stated explicitly to the contrary, it is not stated, and these principles apply.

Rather, the proof is from that which we learned elsewhere in a mishna: If a city that belongs to a single individual subsequently becomes one that belongs to many people, one may establish an eiruv of courtyards for all of it. But if the city belongs to many people, and it falls into the possession of a single individual, one may not establish an eiruv for all of it, unless he excludes from the eiruv an area the size of the town of Ḥadasha in Judea, which contains fifty residents; this is the statement of Rabbi Yehuda.

Rabbi Shimon says: