Both Rava and Abaye agree that Shmuel holds that one cannot fictitiously extend the roof to the ground. Therefore, Abaye would be forced to admit that only Rav would agree with him. However, Rava could argue that not only Shmuel but even Rav would agree with him in the case of the sukkah. Rav allowed one to fictitiously extend the roof of the exedra found in the field because the beams that form the edges of the roof were made for the exedra. However, in the case of the exedra in the courtyard the beams that are over the exedra were not made for the sukkah which was placed in the area in between the sides of the exedra. Since these beams were not made for the sukkah, they cannot be fictitiously extended to count as the sukkah’s walls.
Today’s daf continues to deal with the issue of whether we consider the edge of a roof to fictionally descend to the ground so that it forms a wall, which could validate the sukkah.
The Mishnah on 17a allowed one to build a sukkah in the middle of a courtyard which is surrounded by an “exedra,” a portico covered by a roof, but only as long as the walls of the house are not four cubits removed from the skhakh. But if we invoke the principle of assuming that the edge of the roof descends to the ground, we could consider the edge of roof of the exedra, upon which the skhakh rests, to go to the ground and act as a wall. Then this sukkah would be valid even if the skhakh was more than four cubits from the real walls. The mishnah is therefore a difficulty on Abaye who holds that we can consider the edge of the roof of the exedra to extend to the ground.
Rava answers the difficult on Abaye by saying that the mishnah is a case where the beams used for skhakh were placed on a level equal to the roof of the exedra. Thus the roof of the exedra cannot be seen in the sukkah and in such a case there would be no way to bring the roof down to the ground to fictitiously create a wall.
The above tradition of the debate between Abaye and Rava was the Suran version of the debate. This version (part 5 of the previous daf) read: “If one placed skhakh over an exedra which has pillars, it is valid; If it has no pillars: Abaye declares it valid and Rava declares it invalid.” Thus everyone agrees that if the exedra has pillars it is valid and they dispute a case where it doesn’t have pillars.
In Pumbedita they teach a more stringent version of the dispute. In this case, if there are no pillars everyone agrees that it is invalid. This implies that no one says that we can fictitiously extend the roof of the exedra to the ground. They disagree if they have pillars, each of which is less than three handbreadths from the next. Abaye says we invoke the rule of “lavud”—less than a three handbreadth gap is considered as if it doesn’t even exist. Rava says we do not apply this rule.
Finally, the sugya ends saying that we follow the first version of the dispute. Post-talmudic halakhic authorities also rule according to Rava. Therefore if there are pillars, the sukkah is valid because of the principle “lavud.” But if there are no pillars, the sukkah is invalid because we don’t invoke the principle of drawing down the roof to create a wall.
This story ends the discussion concerning the sukkah built in the exedra (it is common for such stories to come at the end of long halakhic discussions). Rav Ashi finds his teacher, Rav Kahana building his sukkah in an exedra that has no pillars. He asks him how he can do such a thing. After all, the accepted halakhah is according to Rava who holds that without pillars, such a sukkah is invalid. Rav Kahana responds by showing him that there actually was one pillar there that could count as the third wall (evidently two walls were real, and a sukkah’s third wall can be as small as one handbreadth.) This sukkah is valid whether this pillar could be seen from within the sukkah, meaning it is within the other two walls, or even if it is outside the sukkah. Such a pillar, even if it can’t be seen within the sukkah, counts as a third wall!
The proof text for this concerns the side-post, the structure needed to create an eruv in the courtyard. This is a post placed next to the gate exiting the courtyard. The side-post need not be visible from within the courtyard to count as a side-post. R. Kahana claims that the same is true for the pillar to count as a third wall in the sukkah. It need not be seen inside the sukkah.
Today’s section begins a new topic.
Our sugya contains four different explanations of the opening baraita (a tannaitic source not found in the mishnah). The first explanation is by the amora Ulla. He takes the baraita to mean that if there are sticks projecting out the back of the skhakh of a sukkah, the area under the sukkah is considered to be part of the sukkah. As we shall see in a moment, this halakhah is quite puzzling for it is overly obvious.
The Talmud proceeds to ask a series of difficulties that can be summed up in one question—how can this area underneath the skhkakh projecting out from behind a sukkah count as a sukkah if it doesn’t have the other requirements of a sukkah? The answer to all of these questions is that it does fulfill these other requirements. There are three walls back there, the sukkah is wide enough and there is enough skhakh to provide more shade than sun.
But if this area is simply another sukkah, why does the baraita need to exist? Obviously this space counts as a sukkah.
The answer is that we might have thought that this skhakh couldn’t count for the back sukkah because the skhakh was put there with the intent that it be used for the front sukkah. Therefore, the baraita teaches us that it does count.
Rabbah and R. Joseph say that the baraita refers to a case where the sticks (kosher skhakh) go out in front of the sukkah, on the open side of a three-walled sukkah and there is one wall that goes out with them. We might have thought that the continuation of this sukkah is its own sukkah and it is not valid because it has only one wall. Therefore, the baraita teaches that it is valid. We look at it as part of the sukkah which is covered by the rest of the sticks.
Rabbah b. Bar Hana provides an entirely different interpretation of the above baraita. He would translate it as if it read: “skhakh that goes out of its validity counts as part of the sukkah.” What this means is that if there is a sukkah and throughout most of the sukkah there is more shade than sun, but in one small part there is more sun than shade, the sukkah is still valid. The small portion that has more sun does not invalidate the large portion that has more shade.
R. Oshaia says that the baraita refers to a small sukkah whose dimensions are only 7 x 7 handbreadths. There is a strip of invalid skhakh that is less than three handbreadths. This strip does not invalidate the sukkah. He would translate the words “going out” in the baraita as a strip of skhakh that “goes out” from being valid skhakh for use in a sukkah.
At the end of yesterday’s section, R. Oshiah interpreted a baraita to mean that a sukkah remains valid even if it has a section of invalid skhakh that is less than three handbreadths. Our section begins with a difficulty on this position.
R. Hoshiah raises a difficulty on R. Oshaia (I know, this is confusing). Why would a baraita need to teach that a small sukkah that has less than three handbreadths of invalid skhakh is still valid? Even a gap of less than three handbreadths is not enough to invalidate the sukkah!
R. Abba said that if there is invalid skhakh one can still sleep under it, for it combines with the valid skhakh to create a sukkah. But when it comes to a gap of air, while the space can count towards the sukkah, one cannot sleep under it.
The Talmud asks how the gap in the skhakh can add up to equal the necessary minimum measure for the sukkah but in and of itself is not valid such that one couldn’t sleep under it. Is there another example of such a phenomenon?
R. Yitzchak ben Elyashiv answers in the affirmative! The case is that of a mikveh. If there is fluid clay (mud?) in the mikveh it adds up with the water to create the requisite 40 seahs needed for a valid mikveh. But if one dips in fluid clay alone, without water, it doesn’t count as a mikveh and it doesn’t purify.