Abaye vs. Rava: Today Abaye wins for a change TB Eiruvin 15

Throughout the entire Talmud Rava and Abaye argue on the finer points of Jewish law, halakhah. The halakhah always follows Rava’s opinion except six times   when it follows Abaye’s. There is an acronym that is supposed to help one remember those six occasions and it is יע"ל קג"ם. According to most poskim the “lamed- ל “stands for לחי העומד מאליו the side post that stands by itself. This kind of side post is discussed on today’s daf TB Eiruvin 15.

“It was stated that the amora’im disagreed about a side post that stands by itself, i.e., a side post at the entrance to an alleyway that was not put there for the express purpose of permitting one to carry on Shabbat. Abaye said: It is a valid side post. Rava said: It is not a valid side post.” (Sefaria.org translation) they are basically disagreeing on the purpose of the side post. Abaye believes the main purpose of the side post is to create a Halakhically valid wall, מחיצה. Rava believes the main purpose of the side post serves as a visual reminder, היכר, where the alleyway ends and the public domain begins. “Where they disagree is with regard to a side post. Abaye follows his usual line of reasoning, as he said that a side post serves as a partition, and a partition that stands by itself is a valid partition. And Rava follows his usual line of reasoning, as he said that a side post serves as a conspicuous marker. Therefore, if it was made with a person’s hands for that purpose, it is considered a conspicuous marker; and if not, it is not considered a conspicuous marker.” (Sefaria.org translation)

 Even though Abaye says that side post the stands by itself is a valid side post, it still needs to be designated as such before Shabbat which suggests that even he agrees that a secondary purpose of a side post is one of visual reminder, היכר.

Rava and Abaye argued this point their entire lives. “The Gemara suggests: Shall we say that Abaye and Rava disagree only in a case where they did not rely on it before Shabbat, but in a case where they did rely on it, all agree it is a valid side post? The Gemara answers: This should not enter your mind, as there was a certain balcony [barka] that was in the house of Bar Ḥavu that Abaye and Rava disagreed about their entire lives. The residents of the alleyway began relying on a pillar upon which the balcony rested as their side post. Since Abaye and Rava disagreed about this case, it is clear that their disagreement applies even when the residents had relied on the item as a side post from before Shabbat.” (Sefaria.org translation)

What makes our daf unusual as I stated above is the fact that the halakhah follows Abaye’s position. See Shulkhan Arukh, Orekh Hayyim 363:11