QUESTION: Abaye says that one is Chayav when he throws a mat (from Reshus ha'Rabim) into a pit which is ten Tefachim deep and eight Tefachim wide, if the mat lands on the bottom of the pit. If the mat lands vertically in such a way that it divides the width of the pit and effectively divides it into two pits, each less than four Tefachim wide, then he is Patur. Rebbi Yochanan, though, is in doubt whether one is Patur in such a case, since the act of transferring from Reshus ha'Rabim to Reshus ha'Yachid occurred simultaneously with the obliteration of the Reshus ha'Yachid.

Why does Abaye say that one is Chayav in the first case? There, too, the thrower obliterated the Reshus ha'Yachid -- by diminishing the depth of the pit -- at the same time that he threw the mat into the pit!

(a) The RITVA (see also MAHARAM) explains that when one throws the mat into a pit, he uses the pit in the normal manner in which it is meant to be used. In such a case, only when the pit is filled completely does it lose its status as a Reshus ha'Yachid. In contrast, when a person throws the mat into the pit and it becomes a vertical divider, his use of the pit is not the normal manner of use (storage), and therefore it effectively diminishes the dimensions of the pit.

(b) The RASHBA explains that, normally, in both cases -- when the mat lands horizontally and when it lands vertically -- the use of the pit is considered to be the normal manner of use, and in neither case should the pit lose its status. The second case (when the mat lands vertically) refers to a case in which the thrower explicitly expressed his intent to diminish the dimensions of the pit by leaving the mat there. Consequently, if he did not express his intent, then the pit does not become nullified, even if the mat lands vertically.

(c) RASHI does not explicitly discuss why Abaye says that one is Chayav in the first case. Rashi merely says that it is obvious that one is Chayav, and Abaye mentions it only because of the second case. Rashi clearly does not learn the Gemara in the same way as the Ritva and Rashba (who learn that there is a Chidush even in the first case). Rashi seems to understand that the depth of the pit was actually greater than ten Tefachim, and Abaye mentions "ten" only because that is the measurement that is needed to make a Reshus ha'Yachid. The eight Tefachim in the width, though, is exact.

QUESTION: Abaye states that one is Chayav when he throws an object from Reshus ha'Rabim into a pit that is ten Tefachim deep and four Tefachim wide and is full of water, because water does not "nullify the walls" of the pit. The Gemara cites proof for Abaye's ruling from a Beraisa. In the Beraisa, the Rabanan rule that when one throws an object from Reshus ha'Rabim into the sea, he is Patur. Rebbi Shimon says that if the object falls into an area in the sea which is ten Tefachim deep and four Tefachim wide, he is Chayav. We see from Rebbi Shimon's opinion that water inside a pit does not nullify the pit.

What is the Gemara's proof for Abaye's opinion? While Rebbi Shimon's ruling may support Abaye's ruling, the Rabanan argue with it! The Rabanan apparently maintain that water does nullify the walls of the pit so that it is no longer considered a Reshus ha'Yachid.

(a) The TOSFOS HA'ROSH explains that Rebbi Shimon does not argue with the Rabanan; rather he adds to their ruling. The Rabanan refer to a case in which there was no pit in the sea, and Rebbi Shimon adds that if there was a pit in the sea into which the object fell, the thrower would be Chayav (even according to the Rabanan).

(b) The RA'AVAD (Hilchos Shabbos 14:6) explains that the Rabanan argue with Rebbi Shimon only in the case in which a sea covers the pit, and the water is not only inside the pit but above it as well. The water, therefore, serves to eliminate the presence of the pit. When the pit is on dry land, though, the Rabanan agree with Rebbi Shimon that the water inside of the pit does not nullify it.

There are a number of ways to understand the Ra'avad's explanation:

1. The most straightforward interpretation of the Ra'avad's words is that the water that covers the walls of the pit obliterate its Mechitzos, since they are no longer on the surface.

2. Some Rishonim (RASHBA, RAMBAN) apparently understand that the reason why water does not nullify the walls of a pit is because the walls are still visible. When a pit is filled with objects, such as fruit, the objects nullify the walls of the pit because the walls are no longer visible (MAGID MISHNEH). Perhaps this is also the intention of the Ra'avad. The Rabanan maintain that a pit in the sea is not considered a Reshus ha'Yachid because the walls are not visible, due to the abundance of water on top of it. They agree, however, that a pit full of water on dry land is considered a Reshus ha'Yachid, because its walls are visible.

3. The RAN explains that since the sea that covers the pit is a Karmelis, the object first landed in a Karmelis before it entered the pit, and therefore the thrower is exempt.

(c) The RAMBAM (Hilchos Shabbos 14:6) explains that the argument in the Beraisa involves a pit that is in the sea. Since the sea is a Karmelis, the Rabanan maintain that the pit in the Karmelis is also considered a Karmelis, even though it has the dimensions of a Reshus ha'Yachid. Rebbi Shimon maintains that even though the pit is located in a Karmelis, it still retains its status of a Reshus ha'Yachid. The Rabanan agree that on dry land, a pit filled with water is still considered a Reshus ha'Yachid.

The Rishonim (see Ra'avad) argue with the Rambam's assertion that a pit in a Karmelis is not considered a Reshus ha'Yachid. It seems that the Rambam himself retracts his opinion as well (and thus his answer to our question is also retracted). The RASHBA cites a letter written by the Rambam to the scholars of Lunil in which he writes that a mistake was made in the reproduction of the Mishneh Torah. Instead of saying that a pit that is ten Tefachim deep and four Tefachim wide is not a Reshus ha'Yachid if it is in a Karmelis, it should read that a pit that is ten Tefachim deep and not four Tefachim wide is not a Reshus ha'Yachid in a Karmelis.

QUESTION: Abaye states that when one fills a pit with fruit, the fruit serves to annul the walls of the pit ("Mevatel Mechitzos"), and the pit is no longer considered Reshus ha'Yachid. This ruling seems to contradict the Gemara earlier (99b) that says that if a person throws a fig that sticks to a wall four Amos away, he is Chayav, because the fig does not become part of the wall to which it is affixed and does not diminish the four-Amah distance between the thrower and the wall. Here, however, the fruit is considered to become part of the pit so that it fills the pit and eliminates it. Why is the fig on the wall different than the fruit in the pit in this respect?

(a) TOSFOS (DH Peiros) answers that when one throws a fig onto the side of a wall, he does not leave the fig to become subordinate to the wall the way that one leaves fruit to become subordinate to a pit. Perhaps Tosfos' intention is, as the RAMBAN maintains, that since the fig eventually will fall off of the wall, it does not become part of the wall. The fruit, however, will remain in the pit indefinitely until someone removes it.

(b) Tosfos suggests further that a small amount of fruit (such as the fig stuck to the wall) does not become part of the wall. However, when a lot of fruit is placed in a pit, the fruit becomes part of the pit and nullifies the walls of the pit.

It seems that RASHI (DH Chayav) agrees with this approach. He adds, however, that only when the pit is entirely filled with fruit does that fruit serve to annul the walls of the pit. If the pit is not completely filled with fruit, then the pit is still considered to be in existence and is a Reshus ha'Yachid.

(c) RABEINU CHANANEL and the RAMBAN explain that the Gemara earlier does not mean that the fig does not become part of the wall. Rather, it becomes part of the wall (like the fruit becomes part of the pit) only after it lands on the wall. After it has landed, the distance from the wall to the person is measured from the end of the fruit (and thus it will be less than four Amos). At the time that he threw the fig, though, there were exactly four Amos between him and the point on the wall where the fig landed. The Gemara here, too, refers to a case in which one threw an object into a pit that was already filled with fruit. The fruit diminishes the measurements of the pit so that when the person throws another object into the pit, he has not thrown into a Reshus ha'Yachid.

(d) The Ramban cites an answer in the name of TOSFOS who says that when the Gemara says that fruit serves to nullify the walls of the pit, it refers to fruit of Tevel. Since one may not move Tevel on Shabbos, the fruit must remain in the pit and thus the pit is considered to be nullified. The fig, though, is not Tevel, and since it may be moved on Shabbos it does not become part of the wall.

(e) The TOSFOS RID explains that the two Sugyos indeed argue which each other. The Gemara here maintains that fruit does serve to annul the walls of the pit, while the earlier Gemara maintains that fruit does not serve to annul the walls of the pit.

QUESTION: The Mishnah states that a sea is considered a Karmelis. The MISHNAH BERURAH (345:49) points out that it seems that a sea should be considered a Reshus ha'Yachid. After all, it is more than four by four Tefachim wide, and at any side it has a slope that descends so that the floor of the sea is at least ten Tefachim deep. Why, then, is the sea not considered a Reshus ha'Yachid, with the slope at its sides considered its Mechitzos?

(a) The MAGEN AVRAHAM (345:13) answers that the slope that descends to the seabed is considered a Mechitzah only when it slopes to a depth of ten Tefachim within a distance of four Amos (as the Gemara says on 100a). The sea under discussion is one that does not have such a steep slope.

(b) The ME'IRI and RITVA (in Eruvin 22a) explain that even if the walls of the sea do descend steeply, the sea cannot be considered a Reshus ha'Yachid because its walls are so far apart from each other.