How do you determine the halakha? TB Yevamot 42

 I have written before why they Mishna includes disagreements. Our tradition teaches that each sage’s opinion is holy. Beit Hillel and Beit Shammai argued who held the correct position for over three years. Finally a Bat Kol, “a Divine Voice from heaven, emerged and proclaimed: Both these and those are the words of the living God.” (Eruvin 13b, Sefaria.org translation) Even though both were words of the living God, one cannot simultaneously carry out what one side permitted and the other side forbad. Rules had to be formulated to determine which opinion is to be followed.  TB Yevamot 42 shares one of these rules. To understand the Gemara, one has to understand the term stam Mishna. A stam Mishna is an anonymous or unattributed Mishna. A stam Mishna was Rabbi Yehuda HaNasi way of indicating a majority position. The Mishnah back on daf TB Yevamot 41a presents three different positions how long different women must wait before she may marry, an anonymous one, Rabbi Yehuda’s, and Rabbi Yosei’s. Here is the Mishnah.

“A yevama may neither perform ḥalitza nor enter into levirate marriage until she has waited three months from the time of her husband’s death. And similarly, all other women may not be betrothed and may not marry until they have waited three months since their previous marriage ended. This waiting period is necessary so that, should a woman give birth shortly after remarrying, it will be obvious who the father of the child is. This applies both to virgins and non-virgins, both to divorcées and widows, and both to women who were married to their previous husbands and women who were only betrothed. All of these women must wait three months before remarrying even though for some of them the reason for doing so does not apply.

“Rabbi Yehuda says: The women who were married to their previous husbands may be betrothed, and the women who were only betrothed to their previous husbands may marry without waiting three months. This is true except for the betrothed women that are in the area of Judea, due to the fact that the groom is familiar with her. The custom in Judea was for the couple to be secluded together before the marriage so that they would become familiar with each other. This led to the possibility that they might cohabit even during their betrothal period. Rabbi Yehuda holds that one does not need to wait three months whenever the reason for doing so does not apply.

“Rabbi Yosei says: All of the women may be betrothed within three months even if they were previously married, except for a widow, due to the mourning period she must observe for her deceased husband.” (Sefaria.org translation)

Daf TB Yevamot 42 provides us with a helpful rule when the unattributed Mishna is the accepted halakha. It all depends where the unattributed opinion in the Mishna is found in the dispute. “When Rabbi Zerika went and asked, Rabbi Abbahu said to him: The one who raised this contradiction to you is clearly not concerned for his flour; this is a case of an unattributed ruling followed by a dispute on that ruling, and in such cases the halakha is not necessarily in accordance with the unattributed opinion. As Rav Pappa said, and some say it was Rabbi Yoḥanan who said the following principle: When the Mishna first records a dispute, and afterward it records only one side of that dispute as an unattributed opinion, then the halakha is in accordance with the unattributed opinion. However, when the Mishna first records an unattributed opinion and afterward records that the ruling is subject to a dispute, the halakha is not necessarily in accordance with the unattributed opinion. In each case, the later reference is considered to be a summary of the matter.

§ The Gemara relates: Rabbi Abbahu would walk while leaning upon the shoulder of Rabbi Naḥum, his attendant, and along the way Rabbi Naḥum would walk and gather halakhic rulings from him. Once, Rabbi Naḥum asked him: When the Mishna first records a dispute, and afterward it records only one side of that dispute as an unattributed opinion, what is the halakha? Rabbi Abbahu said to him: The halakha is in accordance with the unattributed opinion. Rabbi Naḥum then asked: When the Mishna first records an unattributed opinion and afterward records that the ruling is subject to a dispute, what is the halakha? Rabbi Abbahu said to him: The halakha is not necessarily in accordance with the unattributed opinion.

“Rabbi Naḥum asked: When a ruling is recorded in the Mishna as unattributed and it is subject to a dispute in a baraita the baraitot (a non-canonical tannaitic source-gg), what is the halakha? Rabbi Abbahu said to him: The halakha is in accordance with the unattributed opinion in the Mishna. Rabbi Naḥum then asked: When the Mishna records that a matter is subject to a dispute, and only one side is recorded as an unattributed opinion in a baraita, what is the halakha? Rabbi Abbahu said to him: if Rabbi Yehuda HaNasi had not taught that ruling in the Mishna, from where would Rabbi Ḥiyya, his disciple and redactor of, have known it? Since the source of the unattributed ruling in the baraita is certainly the dispute recorded in the mishna, its lack of attribution in the baraita only reflects the fact that Rabbi Ḥiyya ruled in accordance with that opinion, but that cannot be used to indicate that it is the accepted halakha.” (Sefaria.org Translation)

Nothing is simple, even this rule. The Rishonim try to clarify this rule, but only end up in disagreeing on what exactly is an unattributed Mishna and does it matter that a contradictory opinion in a Mishna is in a different place impacts this rule?