1) WHICH ACTS OF "HOTZA'AH D'RABANAN" ARE COUNTED BY THE MISHNAH?
OPINIONS: The Gemara says that the Mishnah includes in its count of four additional Hotza'os only those that are forbidden mid'Rabanan and could lead to a transgression mid'Oraisa (and a Chiyuv Chatas). What are those acts of Hotza'ah that are mid'Rabanan?
(a) RASHI and RABEINU CHANANEL explain that the Mishnah counts acts of Hotza'ah in which a person performed an Akirah, for in such cases he could have completed his action and performed a Hanachah, making himself liable.
(b) The RIVA (cited by Tosfos DH Peturi), the BA'AL HA'ME'OR, and the teachers of Rashi (cited by Rashi) explain that the Mishnah counts act in which a person extends his hand from one Reshus to another Reshus, for such acts closely resemble the Melachah d'Oraisa, which involves transporting an object from one Reshus to another.
Rashi explains the logic of this approach in a slightly different way. He explains that the person who passes his hand from one Reshus to another initiates the Melachah by doing the first motion involved. (See SEFAS EMES for a novel understanding of the Riva's explanation.)
(c) The RAMBAN and RASHBA mention that according to others, the Mishnah counts only acts of Hanachah. The Hanachah completes the Melachah, and it is at the point of Hanachah that a person would be liable had he done an entire Melachah. That is why it is more similar to Hotza'ah d'Oraisa and is counted in the Mishnah.
2) EXTENDING HIS HAND INTO RESHUS HA'RABIM
QUESTION: One Beraisa says that when a person extends a hand full of fruit from Reshus ha'Yachid to Reshus ha'Rabim but keeps his hand within ten Tefachim of the ground, it is forbidden to bring his hand back to Reshus ha'Yachid. Why can he not simply lift up his hand to a level higher than ten Tefachim from the ground (which would constitute a Makom Petur) and then bring his hand back into Reshus ha'Yachid (since transferring from a Makom Petur to a Reshus ha'Yachid is permitted)?
(a) TOSFOS (DH Kan l'Ma'alah) says that this indeed would be permissible.
(b) According to one opinion in the Gemara in Eruvin (85b), it is forbidden to transfer from a Karmelis to a Makom Petur.
(c) The RASHBA explains that the Rabanan prohibited this due to a concern that he might bring his hand directly back into his Reshus without first lifting it up higher than ten Tefachim.
(d) Perhaps lifting his hand above ten Tefachim and then bringing his hand back to Reshus ha'Yachid would not be considered bringing it from a Makom Petur into Reshus ha'Yachid, because he never rested his hand or its contents in the Makom Petur. Since his hand only passes through a Makom Petur, it is not considered as being brought from a Makom Petur to a Reshus ha'Yachid, but rather it is considered as being brought directly from a Karmelis to a Reshus ha'Yachid, which is prohibited. (M. KORNFELD)
3) RAV BIVI'S QUESTION
QUESTIONS: Rav Bivi asked whether or not it is permitted for one who affixed dough to the sides of a lit oven on Shabbos to remove it ("Rediyas ha'Pas") before it is baked. The Gemara asks why we do not infer the answer to his question from the explanation given to reconcile the two Beraisos regarding whether or not a person who extended his hand outside on Shabbos while holding fruit is permitted to return his hand to Reshus ha'Yachid. In one of its answers, the Gemara resolves the contradiction between the two Beraisos by saying that the Rabanan prohibited a person from bringing his hand back into his Reshus when he put his hand out on Shabbos, even though such a decree may cause him to transgress a Melachah d'Oraisa (he might become tired and cast down the contents of his hand into Reshus ha'Rabim). The Gemara replies that we cannot infer an answer to Rav Bivi's question from the Gemara's answer for the Beraisos, because "in this case it is Shogeg, and in this case it is Mezid."
RASHI explains that the words, "in this case it is Shogeg, and in this case it is Mezid," refer back to the two Beraisos. The Gemara is saying that Rav Bivi's question can be resolved neither from the case of Shogeg nor from the case Mezid, because the case of the outstretched hand is more strict in one respect, and more lenient in another respect, than the case of removing the bread from the oven. Perhaps only in the case of one who inadvertently extended his laden hand into Reshus ha'Rabim do the Rabanan permit him to bring his hand back in, because there was no pre-existing prohibition mid'Rabanan against bringing his hand back into the Reshus in which he is standing. In the case of Rav Bivi, however, there is a pre-existing prohibition mid'Rabanan against removing dough from the sides of an oven, and therefore the Rabanan did not relax their prohibition, even though this stringency will lead to a transgression of an Isur d'Oraisa.
On the other hand, perhaps only in the case of one who knowingly extended his laden hand into Reshus ha'Rabim on Shabbos do the Rabanan prohibit him from bringing his hand back in, because the Rabanan know that a person would not jeopardize his life by throwing the object down and being liable to the death penalty, and it is very likely that he will not cast the object down. In Rav Bivi's case, however, if the Rabanan uphold their decree, the person will definitely transgress an Isur d'Oraisa when the bread is baked (for it is not in his ability to avoid the transgression), and therefore perhaps they do not forbid him from removing the dough.
(a) Why does Rashi not give a much simpler explanation for the words of the Gemara? When the Beraisa says that it is forbidden to bring back his hand, it is talking about when he deliberately extended his laden hand, while Rav Bivi refers to a case in which he put the dough on the oven unintentionally, and therefore the Rabanan do not forbid him to remove it!
(b) If the Gemara is saying that Rav Bivi's case is, in one sense, more strict than the case of the outstretched hand, while in another sense it is more lenient, then why does the Gemara have to differentiate at all between "Shogeg" and "Mezid"? The Gemara can retain its original answer, that one Beraisa refers to when he extended his hand before Shabbos ("mib'Od Yom") and the other Beraisa refers to when he extended his hand on Shabbos ("mishe'Chashechah"), and the differences between Rav Bivi's case and the case of the outstretched arm will still exist! Why, according to Rashi's explanation, does the Gemara have to give a new resolution for the Beraisos?
(a) The Gemara later (4a) concludes that the case of Rav Bivi refers to when one placed dough into the oven intentionally. Rashi, therefore, explains that the words, "in this case it is Shogeg," do not refer to the case of removing bread from the oven (since that case was not Shogeg), but rather to one of the two Beraisos that discuss the outstretched hand.
(b) From the wording of the Gemara it is clear that the question on Rav Bivi (why he did not resolve his question from the Beraisa that prohibits one to return his laden hand to Reshus ha'Yachid) applies only if we say that there is a difference between extending one's hand before Shabbos and extending it on Shabbos, and extending it on Shabbos is treated as more severe. (That is, even though a decree prohibiting him from returning his hand to his Reshus in such a case may lead to a severe transgression of Hotza'ah, nevertheless the Rabanan make such a decree.) Since this would be the opposite of Rav Bivi's proposed logic (that if the decree will lead to a transgression of an Isur d'Oraisa, then perhaps the Rabanan do not uphold their decree in such a case), the Gemara sees it as a resolution for Rav Bivi's question (and the Rabanan do uphold their decree in Rav Bivi's case). Otherwise, why did the one who gave the resolution for the two Beraisos not give the opposite answer (that extending one's hand before Shabbos is considered more severe, because doing so will not lead to a transgression of an Isur d'Oraisa)?
The Gemara replies that we misunderstood the previous statement of the Gemara. When the Gemara says that one Beraisa refers to when he put out his hand "before Shabbos," it means that he put his hand out b'Shogeg (because normally one is not thinking about Shabbos when he stretches out his hand before Shabbos starts.) When the Gemara says that the other Beraisa refers to when he put out his hand on Shabbos, it means that he put out his hand b'Mezid. Hence, the Gemara's real differentiation between the Beraisos was not between "before Shabbos" and "on Shabbos," but rather between Shogeg and Mezid! Since the Gemara is no longer proposing a logic opposite to that of Rav Bivi's, we cannot resolve Rav Bivi's question based on the Gemara's statements (since there is reason to be either more or less stringent in the case of the outstretched hand, as Rashi explains). (M. KORNFELD)