1) THE FIRE LIT BY THE DOG
QUESTION: The Gemara attempts to prove the view of Rebbi Yochanan, who says "Esho Mishum Chitzav," from the Mishnah (21b). The Mishnah states that when a dog takes a Chararah, a cake baked on coals, with a coal and carries it to someone's Gadish (pile of grain) and ignites the Gadish with the coal, the owner of the dog must pay Nezek Shalem for the damage done to the Chararah, and he must pay Chatzi Nezek for the Gadish. According to Rebbi Yochanan, the reason why he must pay Chatzi Nezek is clear: the Esh spread by a dog is like a stone kicked by a dog (Tzeroros), since a fire that spreads as a result of someone's actions is considered "Kocho." Therefore, the owner pays Chatzi Nezek for the Gadish because of the Halachah that for damages of Tzeroros one pays Chatzi Nezek.
However, according to Reish Lakish who says "Esho Mishum Mamono," the owner should not have to pay anything for the Gadish since the fire was not the property (Mamon) of the owner of the dog. Reish Lakish answers that the owner of the dog indeed is exempt from damages caused to most of the Gadish; he must pay only for the damage done to the place at which the dog placed the coal since that is considered damage caused directly by his animal. (This form of damage is included in the category of Regel. The dog which takes the coal and puts it down it in a place where it causes damage is similar to an animal that walks through Reshus ha'Rabim and kicks an object to a place where it causes damage; see 6a.)
Why does the owner of the dog pay Chatzi Nezek for the damage done to the place where the coal was placed? Reish Lakish explains "d'Adyei Aduyei" -- the dog tossed the coal onto the pile of grain.
The simple meaning of his statement is that the owner pays only Chatzi Nezek because the coal is like Tzeroros, since it was tossed by the dog onto the Gadish and it was not placed there by the dog directly. This is how RASHI first explains (DH Meshalem Chatzi Nezek), and the way the RA'AVAD, TOSFOS RABEINU PERETZ, and others explain. However, Rashi adds a "Lishna Acharina" in which he explains the Gemara differently: when the dog tossed the coal, it was considered an unusual way to cause damage. Hence, the reason why the owner pays Chatzi Nezek is that the damage was an act of Keren.
What does Rashi gain with this "Lishna Acharina"? If the dog tossed the coal, then whether it tossed it in a usual manner or in an unusual manner the owner must pay Chatzi Nezek because of the law of Tzeroros. Why does Rashi add that he also must pay Chatzi Nezek because it is an act of Keren (i.e. Tzeroros of Keren) and not Regel? (SHITAH MEKUBETZES in the name of TALMIDEI HA'RAV REBBI YISRAEL)
ANSWER: The TALMIDEI HA'RAV REBBI YISRAEL suggest that Rashi writes this additional explanation because of the Beraisa cited earlier (18a) which teaches that the Chatzi Nezek of the Mishnah is paid "mi'Gufo." If the owner of the dog pays Chatzi Nezek because of Tzeroros, then the Mishnah is proof that Chatzi Nezek of Tzeroros is paid mi'Gufo. Furthermore, if the obligation in this case is because of Tzeroros, why does Rebbi Elazar argue with the Tana of the Mishnah and rule that the owner pays Nezek Shalem mi'Gufo? For these reasons, why Rashi suggests that the damage was done through Tzeroros of Keren, and for Tzeroros of Keren one certainly pays mi'Gufo since even for damages of normal Keren one pays mi'Gufo. This is the way the Gemara earlier (18b) explains the Mishnah according to Rava.
However, ha'Rav Rebbi Yisrael questions this explanation. Why does the Gemara need to explain that the dog tossed the coal onto the Gadish? If the Gemara, according to Rashi, wants to avoid proving that Tzeroros is paid mi'Gufo, it should explain that the dog placed the coal on the Gadish in an unusual manner, such that no damage of Tzeroros is involved. The reason the owner pays Chatzi Nezek is because of Keren, and not because of Tzeroros! Ha'Rav Rebbi Yisrael leaves this question unanswered.
Perhaps an answer may be gleaned from the words of RABEINU CHANANEL who defines "d'Adyei Aduyei" differently. He explains that the Gemara means that the dog did not lift the coal off of the ground, but rather shoved it ("Medadeh") along the ground to the Gadish in an unusual way. (Rabeinu Chananel may have read the Gemara as "Dadyei Deduyei" instead of "d'Adyei Aduyei.")
According to this explanation, the Gemara indeed means that the dog placed the coal on the Gadish in an unusual way which did not involve Tzeroros, just as ha'Rav Rebbi Yisrael suggests, and this explains the reason for Rashi's "Lishna Acharina."
(b) The Gemara (18b) offers another explanation for the Mishnah. It says that the Mishnah refers to a case of an act of Tzeroros that was repeated three times, and that is why Rebbi Elazar rules that one pays Nezek Shalem. However, half of that Nezek Shalem is paid mi'Gufo because of the "Tzad Tamus" that remains. Rashi there offers two ways to understand this answer: either the Mishnah is discussing Tzeroros of Keren, or it is discussing Tzeroros of Regel. (See Insights there.)
Accordingly, both explanations of Rashi here might relate to this explanation of the Gemara (on 18b), and Rashi's two Leshonos here correspond to the two Leshonos that he offers there (18b) with regard to whether the case is one of Tzeroros of Keren or Tzeroros of Regel.
According to this answer, ha'Rav Rebbi Yisrael's question no longer applies. The Gemara does need to explain that the damage was done in a manner of Tzeroros in order to show why Rebbi Elazar -- who argues with the Tana of the Mishnah -- requires the owner to pay Nezek Shalem. (M. Kornfeld)

22b----------------------------------------22b

2) ONE WHO IGNITES AN "EVED" TOGETHER WITH A PILE OF GRAIN
QUESTION: The Gemara quotes the Mishnah later (61b) which teaches that when a person ignites a Gadish in which a bound Eved lies and the fire kills the Eved, he is exempt from paying for the damages to the Gadish or to any animals inside of it, because he is Chayav Misah, and the law is that "Kam Lei bid'Rabah Minei" -- one who is Chayav Misah is exempt from Tashlumin, monetary payments. The Gemara explains that according to Rebbi Yochanan, he is Chayav Misah for lighting the fire that killed the Eved because "Esho Mishum Chitzav," and lighting a fire is comparable to shooting an arrow. According to Reish Lakish, who maintains that "Esho Mishum Mamono," the Mishnah must be referring to a person who set fire directly to the body of the Eved and then the fire spread through the Gadish, because if he set fire to the nearby Gadish which then spread to the Eved he would not be Chayav Misah for killing the Eved.
It is clear from a number of sources that the law of "Kam Lei" applies only when the Chiyuv Misah and Chiyuv Mamon come simultaneously (see Kesuvos 30b). Why, then, should the rule of "Kam Lei" apply here? According to Rebbi Yochanan, the Gadish was burned before the Eved was killed, while according to Reish Lakish, the Gadish was burned after the Eved was killed! According to both views, the Gadish and Eved were not burned at the same time. Why, then, does "Kam Lei bid'Rabah Minei" apply to exempt the person from payment? (RASHBA)
ANSWERS:
(a) The TALMID HA'RASHBA V'HA'ROSH cites the Gemara in Kesuvos (31a) which teaches that when a person throws an arrow four Amos in Reshus ha'Rabim on Shabbos, and the arrow tears someone's shirt in its flight, the person who threw the arrow is Chayav Misah (for desecrating Shabbos) and is exempt from paying for the shirt. The Gemara explains that although the Chiyuv Misah comes only at the time that the arrow comes to rest, and the shirt was torn before that moment, it is considered as though the two Chiyuvim occur at the same time. This is because from the moment that the arrow left his hand it cannot be retracted, and it is already clear at that moment that damage will be done to the shirt and that Shabbos will be desecrated.
The same answer may be applied here. After the fire in the Gadish was lit, it inevitably will spread to the Eved, or if it was lit first on the Eved, it will inevitably spread to the Gadish, and it cannot be retracted. Therefore, the principle of "Kam Lei bid'Rabah Minei" applies.
The logic for why all of the effects that occur after the throwing of the arrow or the lighting of the fire is done are considered to occur simultaneously, according to RASHI in Kesuvos (31a, DH Lo Matzi), is that from the moment that the arrow was thrown it is considered as if the person did all of the actions that will eventually come about because of his act of throwing (see Insights there).
The NIMUKEI YOSEF here (10a of the pages of the Rif) explains this in greater detail. He asks a general question on Rebbi Yochanan's opinion: If -- because of "Esho Mishum Chitzav" -- a person who lights a fire is considered to have done everything that the fire subsequently accomplishes until it is extinguished, then when a person lights candles before Shabbos and the candles burn through the beginning of Shabbos it should be considered as though the person lit a fire on Shabbos, since the person is considered to have lit the fire at every moment at which the fire burns! The Nimukei Yosef answers that according to Rebbi Yochanan, everything that the fire eventually does was caused at the moment at which the fire was initially lit. Therefore, the act of causing the fire to burn on Shabbos was completed before Shabbos, even though the actual burning took place later on Shabbos.
The Nimukei Yosef cites proof for this from the Halachah that if a person lit a fire and died before the fire caused damage, his heirs are obligated to pay for any damage that the fire causes. If one is liable for the damages of a fire only because he is considered as though he lights the fire at every moment that it burns, he should not be liable since he is dead. It must be that the Chiyuv for any damage that will occur in the future takes effect at the moment the fire is lit.
According to the Nimukei Yosef, it is clear why the person who lights the fire that kills the Eved and burns the Gadish is considered as though he burns the Eved and Gadish simultaneously. Every effect of the fire is considered to have been caused by the one who lit the fire at the moment that he lit it, and therefore both Chiyuvim occur simultaneously at that moment.
The Gemara in Kesuvos, however, presents another explanation for why "Kam Lei bid'Rabah Minei" applies to one who throws an arrow on Shabbos that tears someone's clothing. The Gemara suggests that it is impossible to perform an act of Hanachah to cause the Chiyuv Misah for throwing the arrow without first performing an act of Akirah. Accordingly, the Chiyuv Misah is considered to begin from the time of the Akirah, and the tearing of the shirt takes place simultaneously with the event that causes the Chiyuv Misah. This explanation certainly does not apply to the case of the Gemara here, since it certainly is possible to burn an Eved without burning the Gadish and vice versa.
It should be possible to prove from the Mishnah quoted by the Gemara that the first explanation in Kesuvos is correct and not the second. How is the Gemara to be understood according to the second explanation?
Moreover, the only source cited by the Gemara in Kesuvos for the Halachah that "Kam Lei bid'Rabah Minei" applies to throwing an arrow on Shabbos is a Beraisa of Rebbi Avin. Why does the Gemara there not cite as a source the Mishnah (61b) which the Gemara here cites?
Perhaps the Talmid ha'Rashba v'ha'Rosh understands that the Gemara's second explanation in Kesuvos agrees with the logic of the first explanation. The Gemara merely intends to add, according to the second explanation, that even if it is possible to retract an action that was started (for example, walking with a knife through four Amos of Reshus ha'Rabim and tearing someone's clothing while walking; see the Gemara there), nevertheless "Kam Lei bid'Rabah Minei" applies if the action of the Chiyuv Misah involves an Akirah and a Hanachah, since the Akirah is an integral part of the Aveirah. (This is not true according to some Rishonim there, who explain that even the first explanation would apply only in a case which involves an Akirah and a Hanachah; see Ramban in Insights there.)
The reason why the Gemara cites the Beraisa of Rebbi Avin and not the Mishnah (61b) is because Rebbi Avin states the Halachah more clearly.
(b) The RASHBA explains that the Gemara here is unrelated to the Gemara in Kesuvos. He says that perhaps the reason why "Kam Lei" applies in the case of the Gemara here is that the person who lit the fire is considered a "Rodef" from the moment he lights the fire, since the fire he lit is causing someone's death. The Halachah is that one is permitted to kill a Rodef. The Gemara in Bava Kama (117b) teaches that because of this law, a Rodef who damages objects while running after someone to kill him is exempt because of "Kam Lei." The one who lit the fire is not exempt from paying because of the Chiyuv Misah that applies to him for his act of actually killing the Eved, but rather because of the Chiyuv Misah that applies to him for his act of attempting to kill the Eved, even before the Eved actually dies.
The OR SAME'ACH (Hilchos Rotze'ach) asks a strong question on the Rashba's explanation. The reason why one is permitted to kill a Rodef is in order to prevent him from taking someone else's life. In the case of the Gemara here, killing the one who lit the fire is not going to help to save the Eved. In order to save the Eved, one must stop the fire from burning! Why should one be permitted to kill the one who lit the fire because he is a Rodef?
If one may kill the person who lit the fire so that he will not stop anyone from extinguishing the fire, then even according to Reish Lakish, who says "Esho Mishum Mamono," one should be permitted to kill the person who lit the fire (in order to be able to extinguish the fire and save the Eved). What difference does it make if "Esho Mishum Mamono" or "Mishum Chitzav"? The one who lights the fire should be exempt from paying for the Gadish even according to Reish Lakish because of the Halachah of Rodef!
The answer to this question may be that according to the Rashba, the reason why one is permitted to kill a Rodef is not that the death of the Rodef will save the person he is pursuing, but that the verses in the Torah which discuss "Ba ba'Machteres" (Shemos 22:1) teach that when a person is a Rodef the Torah permits one to kill him. That is, the Torah permits one to kill a Rodef simply because he is a Rodef and not because of an attempt to save the intended victim. Therefore, according to Rebbi Yochanan who says "Esho Mishum Chitzav," the one who lit the fire is considered a Rodef and therefore he may be killed even if doing so will not save the Eved's life. However, according to Reish Lakish who says "Esho Mishum Mamono," a person who lights a fire in the Gadish where the Eved is bound is not considered a Rodef since the fire is what is pursuing the Eved, and not the person who lit the fire. (Reish Lakish maintains that the fire is not considered a direct result of the actions of the one who lit it; it is viewed as a separate entity apart from him, like his animal.) Therefore, according to Reish Lakish the person who lit the fire cannot be killed, and "Kam Lei bid'Rabah Minei" should not apply. (See also AVI EZRI, beginning of Hilchos Rotze'ach, and ACHIEZER, Even ha'Ezer 18-19.)
3) TO WHOM DOES A KILLER "OWE" A "CHIYUV MISAH"
QUESTION: According to Reish Lakish, the Mishnah which discusses one who ignites an Eved, Gadish, and goat, teaches that "Kam Lei bid'Rabah Minei" applies even when the goat that was burned did not belong to the owner of the Eved who was burned. That is, although the Chiyuv Misah is for one person and the money he is exempt from paying was owed to another person, "Kam Lei" still applies.
Why does the Gemara need to explain that the goat did not belong to the owner of the Eved? The Chiyuv Misah for killing the Eved is not something "owed" to the owner of the Eved, but it is something that is "owed" to the Eved who was killed! As long as the goat does not belong to the Eved, "Kam Lei" applies when the Chiyuv Misah and Tashlumin are in response to acts done to two different people. (TOSFOS, end of DH b'Gedi)
TOSFOS adds that it is clear that the Chiyuv Misah for killing the Eved is not "owed" to the master from the fact that if the master kills his own Eved he is still Chayav Misah. When he merely damages his Eved, however, he is exempt from payment (Bava Kama 87a) because he is the one who receives payment for any damages done to the Eved. If, when he kills the Eved, he is Chayav Misah, then obviously he is not the one who owns the Eved's life with regard to the Chiyuv Misah for killing the Eved.
ANSWER: Perhaps the Chiyuv Misah for killing the Eved indeed is something "owed" to the master of the Eved. The Torah implies that when a person is executed for committing murder, his death in some way is "compensation" for the other's life that he killed. Just as the Torah says that a person pays damages for knocking out someone's eye as compensation for the eye, "Ayin Tachas Ayin" (Shemos 21:24), so, too, it says that a person who kills someone pays "Nefesh Tachas Nafesh" -- "a life for a life" (Shemos 21:23). (See KUNTRESEI SHI'URIM, Shi'ur 21.) Just as the payment for the damage done to the eye must be paid to the owner of the Eved, the Chiyuv Misah for killing the Eved is also "paid" to the owner of the Eved.
Regarding Tosfos' question, why is the Eved's owner Chayav Misah when he kills his own Eved, perhaps the Gemara maintains that the Chiyuv Misah is not only "owed" to the master, but also to the Eved. Why is it different from the payment for bodily damage done to the Eved which does not involve death and which is paid exclusively to the owner? (The answer cannot be that the master does not own his Eved with regard to the Eved's life, because he does not own the Eved with regard to his body either. See RASHI to Gitin 21a, DH Lo Efshar.) Perhaps the reason is that the Torah gives to the master only the rights to any material payment due to the Eved but not the rights to payments such as "Nefesh Tachas Nefesh," since the Eved would not receive anything material. Therefore, if the master kills the Eved, he must also "pay" "Nefesh Tachas Nefesh" to the dead Eved. (M. Kornfeld)