The Gemara is interested in clarifying the definitions of some of the terms that it uses in describing the courtyards that need eiruvin and the relationships that exist between them. Generally speaking, a mavoy is the closed alleyway into which a number of hatzeirot – courtyards – open. As we have learned, the residents of the courtyards can arrange to carry by placing a symbolic board at the entrance to the mavoy (see 2a-b). According to Rav, this is only the case if a number of courtyards open into the mavoy (that is to say, the mavoy must have at least two courtyards opening into it, and each courtyard needs at least two houses in it), but Shmuel rules that as long as one hatzer and one house opens into the closed area, it is considered a mavoy.
Rav Beruna sat and recited this halakha stated by Shmuel, that an alleyway containing one house and one courtyard can be rendered permitted for carrying by means of a side post or a cross beam. Rabbi Elazar, a student of a Torah academy, said to him: Did Shmuel really say this? Rav Beruna said to him: Yes, he did. He said to him: Show me his lodging and I will go and ask him myself, and he showed him. Rabbi Elazar came before Shmuel and said to him: Did the Master actually say this? Shmuel said to him: Yes, I did. Rabbi Elazar raised the following objection: Wasn’t it the Master himself who said concerning a different issue: With regard to the halakhot of eiruv, we have only the wording of our mishna. The mishna states that an alleyway is to its courtyards like a courtyard is to its houses, which indicates that an alleyway must have at least two courtyards in order to be considered an alleyway and be rendered permitted for carrying through a side post or cross beam. Shmuel was silent and did not answer him.
Shmuel’s silence is not unique in the Gemara; we find many instances where one of the Sages does not respond to a question posed to him. How to interpret the lack of response, though, is not clear. It could be that the Sage does not have an answer to the question, but it could also be that the Sage does not think that the question is a good one, and feels that it does not deserve a response. Some suggest that every question needs to be evaluated according to the relationship between the people involved. Tosafot suggest that if a student asks the question, the silence may simply indicate a rejection of the question. If a peer asks the question, it likely shows that he had no answer. Nevertheless, even if the Sage has no answer to the question, it does not prove that he is retracting his opinion. The question may not be of great importance (in this case, for example, Shmuel may retain his belief that the mavoy does not need two hatzeirot opening into it, and will back away from his general statement about how to read Mishnayot in this tractate), and not strong enough to reject the halakha.