1) THE GET OF A DEAD MAN
QUESTION: The Mishnah teaches that when an elderly man sends a Get to his wife via a Shali'ach, the Shali'ach may give the Get to his wife and there is no concern that the husband died while the Shali'ach was en route.
RASHI (DH Nosno) explains that the husband is assumed to be alive when the Get is given because of a Chazakah that since he was alive until now, he is assumed to be alive now as well. There is no concern that the husband died and that the Shelichus that he made became annulled.
Rashi implies that if the husband would have died, the reason why the Get would be have been invalid is that the Shelichus would have been annulled. Why does Rashi not write that the Get would have been invalid simply because a man cannot divorce his wife after he dies ("Ein Get l'Achar Misah"), as the TOSFOS RID and ME'IRI write? In fact, Rashi himself gives the reason of "Ein Get l'Achar Misah" in Kesuvos (2b) with regard to a man who writes in a Get that he wants the Get to take effect only after twelve months, and then he dies within those twelve months. Rashi there (DH Mes) explains that such a Get is not valid because a dead man cannot divorce his wife. This is the way the Gemara there itself explains -- a Get that is supposed to take effect only after the husband dies is not valid because "Ein Get l'Achar Misah." (HAGAHOS CHAVOS YA'IR #5 on the Rif)
Moreover, why does the Tosfos Rid here and the Gemara in Kesuvos write that the reason the Get is not valid after death is because a dead person cannot give a divorce? Even if a dead person could give a divorce, the Get should not be valid since a woman is Konah herself through the death of her husband and is no longer in her husband's domain! It is like giving a Get to a woman who is not married. In fact, Rashi uses this argument to explain why a Get Shichrur is not valid in the case of an owner of an Eved who sends a Get to his Eved with a Shali'ach, and the owner dies before the Get reaches the Eved. The reason the Get Shichrur is not valid is that the Eved no longer belongs to him; the Eved now belongs to the master's heirs (Rashi to Gitin 9b and 13a, DH Lo Yitnu).
ANSWER: The DIBROS MOSHE explains the words of Rashi as follows. TOSFOS (13a, DH Lo Yitnu) asks why the Mishnah (13a) needs to teach that when a man sends a Get to his wife and dies before it reaches her, the Get is not valid, when another Mishnah (72a) already teaches that a Get cannot take effect after the husband's death.
Tosfos answers that the Mishnah there (13a) wants to teach that even if the husband appointed a Shali'ach to deliver the Get to his wife, the Shali'ach cannot give the Get after the husband dies. Had the Mishnah not taught this, one might have thought that if a man writes a Get with the stipulation that it should take effect only after twelve months have passed, and he dies within those twelve months, the Get is not valid because the husband cannot divorce his wife after he is dead. However, if he appointed a Shali'ach to give the Get to his wife, perhaps the Get should be valid. A Shali'ach is in the place of the husband with regard to the Get, and since the Shali'ach is still alive perhaps it is considered as though the husband is still alive and thus he may give the Get. The Mishnah therefore teaches that even a Shali'ach may not give a Get after the death of the husband.
Why, though, may the Shali'ach not give the Get after the husband dies? Is it because the Shali'ach is considered to be like the husband only with regard to the ability to make the Kinyan and not with regard to any other matter (see OR SAME'ACH, Hilchos Gerushin 2:15, and LEKACH TOV #1), or is it because the Shelichus automatically becomes annulled at the death of the husband?
The Tosfos Rid (and perhaps also Tosfos on 13a) follows the first approach. Rashi here follows the second approach; the reason why the Get is not valid is that once the husband dies, the Shali'ach is no longer considered to be a Shali'ach. Had he still had the status of a Shali'ach, the Get would have been valid even after the death of the husband.
Rashi's source for this explanation is the Gemara later (29b), where Mar bar Rav Ashi implies that the death of the husband causes an annulment of the Shelichus (see Hagahos Chavos Ya'ir there).
The Gemara in Kesuvos (2b), on the other hand, refers to a Get which is supposed to take effect after twelve months, and the husband dies before that time arrives. Since there is no Shali'ach involved in that case, the Get does not take effect simply because of "Ein Get l'Achar Misah," a dead man cannot divorce his wife.
Why does the Gemara (and Rashi) need to explain that a dead person cannot divorce his wife? The Gemara (and Rashi) should say simply that after the man's death, the woman is no longer his wife and a Get cannot take effect! The KETZOS HA'CHOSHEN (188:2) and OR SAME'ACH (loc. cit.) explain that when a man dies childless, the Kidushin of the dead husband remains in effect insofar that it causes his wife to be obligated to perform Yibum or Chalitzah with his brother. Accordingly, after his death, his wife is not a "Penuyah" (a completely unmarried woman), but rather an element of the original Kidushin remains and, consequently, the Get still should take effect if not for the principle that a dead man cannot divorce his wife.
(The Dibros Moshe suggests that perhaps even when there is no Yavam, such as when the husband has children at the time he dies, some remnant of the Ishus and Kidushin still remain after his death. (See also SHA'AREI YOSHER.) However, the Mishnah in Kidushin (2a) states that the woman is Konah herself after her husband's death, and thus it is not clear that a Get is able to affect whatever Ishus remains after the husband's death.)
What remains to be explained is why Rashi writes (on 13a) that when a master sends a Get Shichrur to his Eved with a Shali'ach and then the master dies, the Shichrur is not valid because the Eved has already left the master's domain. Why does Rashi not explain there as he explains here, that when the master dies the Shali'ach is no longer a Shali'ach? Consequently, he cannot give the Get to the Eved because he is not the master's Shali'ach.
The Dibros Moshe suggests that perhaps the Shelichus would remain in effect after the death of the master because the heirs presumably want to fulfill their father's desire to free the Eved and thus they leave the Shelichus in force. However, if this is true, then the words of Rashi's do not explain why the Get Shichrur does not take effect; even if the heirs now own the Eved, the Shichrur should take effect because they are freeing the Eved. If, on the other hand, it cannot take effect because the Get Shichrur states that the father is freeing the Eved (and the father, who is dead, is no longer the Eved's owner), then even if the heirs want to re-appoint the Shelichus, the present Get Shichrur cannot take effect.
Perhaps Rashi prefers to give the more basic of the two reasons to explain why the Get Shichrur does not take effect. Rashi writes that the Eved has left the domain of the owner, because this reasoning explains not only why the Get Shichrur cannot take effect after the owner dies, but it also why the Get Shichrur cannot take effect even when the owner sells the Eved before the Get reaches the Eved, even though the Shelichus of the Shali'ach still remains in force. The other reason which Rashi gives (in the Sugya here) -- that the Shelichus becomes annulled -- applies only when the Meshale'ach dies but under no other circumstances. (In contrast, a [living] Meshale'ach's willful retraction of the Shelichus constitutes an entirely different reason for why the Get does not take effect.)
2) A CHAZAKAH THAT THE HUSBAND IS STILL ALIVE
QUESTION: The Mishnah (28a) teaches that if a Kohen travels abroad, his wife may continue to eat Terumah, and there is no fear that her husband died and that she may no longer eat Terumah. The Gemara asks that the Mishnah seems to contradict a Beraisa which teaches that when a person gives a Get to his wife on condition that it will take effect a moment before his death, if he is a Kohen and his wife is a Bas Yisrael she may no longer eat Terumah from that moment out of concern that her husband might die the next moment (and the Get will have taken effect the previous moment). Rava answers that there is no concern that a person died (as the Mishnah implies), but there is a concern that a person will die (as the Beraisa implies). Since there is a concern that the Kohen will die the next moment, his wife (to whom he gave the conditional Get) may not eat Terumah. In contrast, the woman who receives a Get from the Kohen's Shali'ach may rely on the Get and she is fully divorced, because there is no concern that her husband died.
RASHI explains that Rava's logic is that the husband's Chezkas Chayim is able to clarify the Safek about whether or not the husband is alive at the moment the Shali'ach gives the Get. Since he was alive until this moment, he presumably alive now as well. In contrast, the Chezkas Chayim cannot determine that he will be alive in the future (in the following moment), since the Chazakah can determine only a present status and not a future one. Therefore, we must suspect that the husband might die in the following moment, and if the husband stipulated that the Get should take effect the moment before he dies, we must suspect that she is divorced at the present moment.
Why is it so obvious to Rashi that a Chazakah cannot determine a future status (that is, whether the husband is going to die and, consequently, whether the woman is divorced at present)? Although the husband's Chezkas Chayim might not apply, other Chazakos exist which should apply to determine the present status of the woman. She should be permitted to eat Terumah because of her Chezkas Eshes Ish which states that since until now she was married, she is assumed to be married at the present moment as well. In addition, she has a Chezkas Muteres l'Terumah, which states that since until now she was permitted to eat Terumah, she presumably is still permitted to eat Terumah! Since these Chazakos affect the present status of the woman, they should be applicable even in the case where it is not known whether the husband will die the next moment, and she should be permitted to eat Terumah. (SHA'AREI YOSHER 2:9; KOVETZ HE'OROS, Hosafos to Yevamos 69b.)
(a) The PNEI YEHOSHUA (28a, with regard to a different question) explains that when a person writes a Get with a condition that it should take effect at the moment before he dies, the Chezkas Eshes Ish and the Chezkas Muteres b'Terumah lose their power to determine the woman's status with regard to eating Terumah, because the Chazakos have been "weakened" by the fact that the husband definitely wrote and gave a Get to his wife. Although there is a doubt about whether the Get took effect, nevertheless the fact that a Get was given provides strong grounds to suspect that she is no longer married (weakening the Chezkas Eshes Ish) and that she is no longer Muteres b'Terumah (weakening the Chezkas Muteres b'Terumah). The husband's Chezkas Chayim, in contrast, is not weakened by the fact that the husband is eventually going to die, since he might not die during his wife's lifetime (as the Gemara says on 28a).
(b) The SHA'AREI YOSHER argues that the fact that the husband gave a Get to his wife is not enough to weaken the Chezkas Eshes Ish on a d'Oraisa level.
He suggests, therefore, that a Chazakah can determine what happened only when what happened is directly influenced by that Chazakah. For example, in the case of the Gemara here, the Chezkas Chayim can prove that the husband is not dead, since the fact that until now he was alive has direct bearing on whether he is now dead.
In contrast, the Chazakos that a woman is married, and that she is permitted to eat Terumah, do not have direct bearing on whether the husband is going to die the next moment. The only reason they are related to the question of how long he will live in this case is that the husband stipulated that the Get which he gave to his wife depends upon the length of his life. Since the connection between the woman's Chazakah and the man's lifespan is only incidental, the Chazakah that she is his wife cannot address the question of whether or not he will continue to live.