ורבי יהושע היא דלא משגח בבת קול
and the latter statement is in accordance with the opinion of Rabbi Yehoshua, who does not pay attention to a Divine Voice that attempts to intervene in matters of halakha, for according to him, the dispute between Beit Shammai and Beit Hillel has not yet been decided.
ואיבעית אימא הכי קאמר כל היכא דמשכחת תרי תנאי ותרי אמוראי דפליגי אהדדי כעין מחלוקת בית שמאי ובית הלל לא ליעבד כי קוליה דמר וכי קוליה דמר ולא כחומריה דמר וכי חומריה דמר אלא או כי קוליה דמר וכחומריה עביד או כקוליה דמר וכחומריה עביד
The Gemara suggests yet another resolution: And if you wish, say instead that this is what the baraita is saying: Wherever you find two tanna’im or two amora’im who disagree with each other in the manner of the disputes between Beit Shammai and Beit Hillel, one should not act either in accordance with the leniency of the one Master and in accordance with the leniency of the other Master, nor should one act in accordance with the stringency of the one Master and in accordance with the stringency of the other Master. Rather, one should act either in accordance with both the leniencies and the stringencies of the one Master, or in accordance with both the leniencies and the stringencies of the other Master.
מכל מקום קשיא
All of this is suggested to explain the wording of the baraita. In any case, it is difficult to explain the law with regard to the alleyway in Neharde’a, concerning which they simultaneously adopted the stringencies of both Rav and Shmuel.
אמר רב נחמן בר יצחק כוליה כרב עבדוה דאמר רב הונא אמר רב הלכה ואין מורין כן
Rav Naḥman bar Yitzḥak said: In fact, they acted entirely in accordance with the opinion of Rav, and the reason that they required doors and did not rely on the opening in the form of a doorway alone is due to that which Rav Huna said that Rav said: This is the halakha; however, a public ruling is not issued to that effect ab initio. Although Rav maintains that an opening in the form of a doorway is sufficient in an open alleyway, a public ruling is not issued to that effect; rather, the ruling is stringent, in accordance with Ḥananya’s position, and requires doors.
ולרב אדא בר אהבה אמר רב דאמר הלכה ומורין כן מאי איכא למימר
The Gemara asks: And according to the statement of Rav Adda bar Ahava that Rav said, as Rav Adda bar Ahava said that Rav said with regard to the same issue: This is the halakha and a public ruling is issued to that effect, what can be said? Why did the residents of Neharde’a adopt the stringencies of the two authorities?
אמר רב שיזבי כי לא עבדינן כחומרי דבי תרי היכא דסתרי אהדדי
Rav Sheizvi said: The principle of dictating when we do not act in accordance with the stringencies of two authorities applies only in a case where the two stringencies contradict one another. In these types of cases, following both stringencies would result in an internal contradiction.
כגון שדרה וגולגולת דתנן השדרה והגולגולת שחסרו וכמה חסרון בשדרה בית שמאי אומרים שתי חוליות ובית הלל אומרים חוליא אחת ובגולגולת בית שמאי אומרים כמלא מקדח ובית הלל אומרים כדי שינטל מן החי וימות
The Gemara illustrates this principle with an example from the laws governing the spine and skull. As we learned in a mishna: The spine and the skull of a corpse that are incomplete do not impart ritual impurity via a tent as a corpse would; rather, they impart impurity only through contact or if they are carried as individual bones. This basic law was unanimously accepted, but the details were the subject of dispute: How much is considered a deficiency in the spine for this purpose? Beit Shammai say: If it is missing two vertebrae, and Beit Hillel say: Even if it is missing only one vertebra. And similarly, they argued over the deficiency in the skull: Beit Shammai say: It must be missing piece the size of a drill hole, and Beit Hillel say: It must be missing an amount that, when removed from a living person, would cause him to die, which is a larger amount.
ואמר רב יהודה אמר שמואל וכן לענין טריפה
And Rav Yehuda said that Shmuel said: Beit Shammai and Beit Hillel argued likewise with respect to a tereifa, a kosher animal suffering from a wound or illness that will cause it to die within twelve months, and which is prohibited to be eaten even after the required ritual slaughter. Beit Shammai say that an animal is regarded as a tereifa if it is missing two vertebrae, while Beit Hillel hold that it is a tereifa if it lacks even one. In such a situation, a person must not be stringent with regard to the halakhot of tereifa in accordance with the view of Beit Hillel, and at the same time be stringent with regard to the halakhot of ritual impurity of a corpse in accordance with the view of Beit Shammai, for the two disputes relate to the same issue, and one must not act in accordance with two contradictory opinions.
אבל היכא דלא סתרי אהדדי עבדינן
Rav Sheizvi continues: However, in a case where the two stringencies do not contradict one another, we may indeed act in accordance with the stringencies of two authorities. Therefore, the stringencies adopted in the case of the alleyway in Neharde’a were legitimate, for the two stringencies related to two separate issues: Rav’s stringency was that an L-shaped alleyway is regarded like an open alleyway, and Shmuel’s stringency was that an open alleyway requires a door.
והיכא דסתרי אהדדי לא עבדינן מתיב רב משרשיא מעשה ברבי עקיבא שליקט אתרוג באחד בשבט ונהג בו שני עישורין אחד כדברי בית שמאי ואחד כדברי בית הלל
The Gemara challenges Rav Sheizvi’s assertion: Is it true that we do not act in accordance with the stringencies of two authorities in a case where the two stringencies contradict one another? Rav Mesharshiya raised an objection from a baraita: There was an incident involving Rabbi Akiva, who gathered the fruit of a citron tree on the first of the month of Shevat and applied the laws of two tithes to it. After teruma and the first tithe have been separated, an additional tithe is separated from what is left. During the first, second, fourth, and fifth years of the Sabbatical cycle, second tithe is set aside to be taken to Jerusalem and eaten there by its owner, while during the third and sixth years, poor man’s tithe is set aside to be distributed to the needy. When tithing the fruit picked on the first of Shevat, Rabbi Akiva set aside both additional tithes, second tithe and poor man’s tithe: He set aside one in accordance with the statement of Beit Shammai, who say that the new year for trees begins on the first of Shevat, and as that day belongs to the new year, a tithe must be set aside in accordance with the law of that year; and he set aside one in accordance with the statement of Beit Hillel, that the new year for trees is the fifteenth of Shevat, and any fruit picked prior to that date must be tithed in accordance with the law of the previous year. Apparently, Rabbi Akiva adopted for himself two contradictory stringencies.
רבי עקיבא גמריה איסתפיק ליה ולא ידע אי בית הלל בחד בשבט אמור אי בחמיסר בשבט אמור ועבד הכא לחומרא והכא לחומרא:
The Gemara answers: Rabbi Akiva did not act in this way in order to be stringent in accordance with both opinions, but because he was in doubt with regard to his tradition and did not know whether Beit Hillel said the New Year for trees falls on the first of Shevat or on the fifteenth of Shevat, and therefore he acted stringently here and stringently there.
יתיב רב יוסף קמיה דרב הונא ויתיב וקאמר אמר רב יהודה אמר רב מחלוקת בסרטיא מכאן וסרטיא מכאן ופלטיא מכאן ופלטיא מכאן
The Gemara resumes its discussion of alleyways that are open on two opposite sides. Rav Yosef sat before Rav Huna, and he sat and said: Rav Yehuda said that Rav said: The dispute between the anonymous first tanna of the baraita and Ḥananya refers to a case where there is a main street [seratya] from here, on one side of the alleyway, and a main street from here, on the other side. Alternatively, it refers to a case where there is a plaza [pelatya] from here, on one side of the alleyway, and a plaza from here, on the other side.
אבל סרטיא מכאן ובקעה מכאן או בקעה מכאן ובקעה מכאן עושה צורת הפתח מכאן ולחי וקורה מכאן
But if there is a main street from here, on one side, and a valley from here, on the other side, a valley being a karmelit, which is neither a public domain nor a private domain, in which carrying is prohibited on Shabbat by rabbinic decree, or if there is a valley from here, on one side, and a valley from here, on the other side, one constructs an opening in the form of a doorway from here, on one side of the alleyway, and places a side post or a cross beam from here, on the other side. One is thereby permitted to carry in the alleyway even according to the opinion of Ḥananya.
השתא סרטיא מכאן ובקעה מכאן עושה לו צורת הפתח מכאן ולחי וקורה מכאן בקעה מכאן ובקעה מכאן מיבעיא
The Gemara raises a question about this ruling: Now, if you say that where there is a main street from here, on one side of the alleyway, and a valley from here, on the other side, it is sufficient to construct an opening in the form of a doorway from here, on one side, and a side post or a cross beam from here, on the other side, was it necessary to state that these are sufficient if there is a valley from here, on one side of the alleyway, and a valley from here, on the other side?
הכי קאמר סרטיא מכאן ובקעה מכאן נעשה כבקעה מכאן ובקעה מכאן
The Gemara answers: This is what he intended to say: If there is a main street from here, on one side, and a valley from here, on the other side, it is considered as if there were a valley from here, on one side, and a valley from here, on the other side.
ומסיים בה משמיה דרב יהודה אם היה מבוי כלה לרחבה אין צריך כלום
The Gemara continues: And when Rav Yosef reported this ruling, he concluded with a statement in the name of Rav Yehuda himself, without attributing it to one of Rav Yehuda’s teachers: If the alleyway terminated in a backyard, i.e., a closed-off area behind a group of houses, then even if there is a breach in the wall between the yard and the public domain beyond it, nothing is needed on this side of the alleyway, as it is considered closed.
אמר ליה אביי לרב יוסף הא דרב יהודה דשמואל היא
Abaye said to Rav Yosef: This ruling of Rav Yehuda is a ruling of his teacher Shmuel, and not of his other teacher, Rav.