As we saw on yesterday’s daf, Rabbi Yohanan rules that we follow Rabbi Shimon’s opinion in the Mishna (89a) even if the residents of each courtyard made their own eiruv, and we are not concerned that someone will carry from his house into the courtyard, and from there into other yards or gardens. On our daf, Ravina points out another statement made by Rabbi Yohanan that seems to stand in contradiction with this one.
Did Rabbi Yohanan actually say this, that the is in accordance with Rabbi Shimon’ s opinion that all courtyards constitute a single domain, even if each courtyard established an independent eiruv? But didn’t Rabbi Yohanan say that the is in accordance with an unattributed mishna, and we learned: With regard to a wall between two courtyards, ten handbreadths high and four handbreadths wide, they establish two eiruvin, one for each courtyard, but they do not establish one eiruv. If there was fruit atop the wall, these, the residents of one courtyard, may ascend from here and eat it, and those, the residents of the other courtyard, may ascend from there and eat it, provided that they do not take the fruit down from atop the wall to the courtyards. According to Rabbi Yohanan, all the courtyards are considered a single domain. Why may they not bring the fruit down?
Rav Ashi answers that the intention of the Mishna is to forbid carrying the fruit from the top of the wall into one of the houses. Carrying it into the courtyard, however, would be permitted.
In response to this, Ravina quotes a baraita taught by Rabbi Hiyya that in such a case the residents of the courtyard can only eat the fruit on top of the wall, and they cannot bring it down to either courtyard at all. Rav Ashi reacts to this by saying that if Rabbi Yehuda HaNasi did not explicitly teach it in this manner, how would his student, Rabbi Hiyya derive such information?
We must limit Rav Ashi’s statement to very specific circumstances, because if we accepted it as a general principle there would be no reason to compare and contrast Mishnayot and baraitot, which is one of the most basic discussions upon which the Gemara is based. What we can say is that when the baraita contradicts the Mishna or reaches a conclusion that runs counter to the conclusion of the Mishna, we will reject the baraita as being Rabbi Hiyya’s personal opinion, rather than a reliable tradition.