1) THE HUSBAND'S RIGHTS TO RECEIVE "PEIRI PEIROS"
QUESTION: The Mishnah states that according to Rebbi Yehudah, when the husband forgoes his rights to the Peiros (fruits) of the field of his wife, he only loses his rights to the Peiros but not to the Peiri Peiros (the fruits of the fruits). It is clear from the Mishnah that when the husband makes no statement to relinquish his rights to the Peiros, everyone agrees that he has the rights to the Peiri Peiros.
How is the Mishnah's statement to be reconciled with the Gemara earlier (79b) which says that the Rabanan instituted that the husband receives only the Peiros and not the Peiri Peiros?
ANSWERS:
(a) The RIF (79b) points out that the Gemara later (83b) gives an example of the Peiri Peiros to which the Mishnah refers. When the husband sold the produce of the wife's land in order to buy more land, and that second land produced Peiros, those Peiros are called Peiri Peiros. The Rif explains that it is only when the husband did not benefit from the original Peiros -- but rather he sold them and bought land for his wife -- that he receives the Peiri Peiros, because they take the place of the original Peiros from which he received no benefit.
The Gemara earlier (79b) refers to a case in which the wife's animal bore offspring, the offspring was stolen, and the thief was found and is now obligated to pay Kefel (double) to the owner of the offspring. Since the husband receives the offspring (Peiros), the Kefel (Peiri Peiros) goes to the wife. Presumably, the same applies to the offspring of the offspring; since the husband took the original offspring, the next generation belongs to the wife.
(b) However, the other Rishonim disagree with the Rif. They assert that it is not logical that the offspring of the wife's animal belongs to the husband, while the offspring of that offspring belongs to the wife! Rather, TOSFOS in the name of the RIVAN explains that the Gemara there (79b) does not intend to differentiate between Peiros and Peiri Peiros per se. Rather, it differentiates between what is derived directly from the Peiros and what is derived indirectly from the Peiros. If the husband takes fruit and plants it, all of the produce belongs to him since the produce was derived directly from the fruit. If one steals the produce and is caught and must pay Kefel, the Kefel goes to the wife because it comes only indirectly from the produce.
2) RELINQUISHING ONE'S RIGHT TO RECEIVE A BENEFIT
QUESTION: The Mishnah discusses a case of a man who forgoes his rights to the Peiros of his wife's property. The Gemara cites two other cases in which a person relinquishes the rights to something which he or she is legally entitled to receive. Rav Kahana says that a man may make a precondition that he will not inherit his wife's property if she dies, even though he is entitled to inherit it. Rava says that a woman may relinquish her right to receive "Mezonos" (sustenance) from her husband (and in return exempt herself from giving her earnings to her husband) by saying that she does not wish to receive spousal support from him.
The Gemara explains that a woman may forgo her rights to Mezonos because it was the Rabanan who instituted -- for her benefit -- that she receive the Mezonos in the first place. The Rabanan also instituted that if she prefers not to receive the benefits of the Takanah for her benefit, she may decline by saying "Iy Efshi b'Takanas Chachamim." This also seems to be the reason why the husband is able to forgo his rights to inherit his wife's property, and why he may forgo his rights to receive the Peiros of her property. Since the Takanah which grants him those rights was instituted only for his benefit, he may decline to receive them.
Why does the Gemara say that the only way in which one can forgo his or her rights is through the mechanism of "Iy Efshi b'Takanas Chachamim" -- by saying "since the Takanah was made for my benefit, I am entitled to relinquish that benefit"? The Mishnah states that one may be "Masneh Al Mah she'Kasuv ba'Torah" -- one may make a condition which counters what the Torah says (see 56a, and Rashi at the end of the Mishnah here), and that condition effectively alters the Torah's intended destination for the property. If a condition can affect a Torah law, obviously it does not work through the mechanism of "Iy Efshi b'Takanas Chachamim," because a Torah Law is not a Takanah of the Chachamim! "Masneh Al Mah she'Kasuv ba'Torah" works because a person has the right to alter what he otherwise would be entitled to receive, when it comes to monetary matters that affect only him. Accordingly, a person certainly should be able to use a condition (Tenai) to change what the Rabanan entitled him to receive! Why does the Gemara need to mention the separate logic of "Iy Efshi b'Takanas Chachamim," which applies only where the Chachamim made a Takanah for his benefit?
ANSWERS:
(a) TOSFOS (end of DH k'd'Rav Kahana) asks this question on the Mishnah. Why does the Mishnah not say that one may avoid receiving something by stating a Tenai? Tosfos answers that one could use a Tenai to avoid acquiring something, but the words of the Mishnah, "Din u'Devarim Ein Li...," do not connote a Tenai, but rather a removal of his rights, and a removal of rights can be accomplished only when those rights are granted to him by a Takanah d'Rabanan, but not when it is the Torah that gives him those rights. (When Raban Shimon ben Gamliel, in the end of the Mishnah, argues and says that one may not be "Masneh Al Mah she'Kasuv ba'Torah," he means that even if one specified a Tenai he cannot lose the rights to the Yerushah of his wife, and certainly he cannot remove himself from those rights if he says only "Din u'Devarim Ein Li....")
However, this does not explain why Rav Kahana -- who says that a person may make a Tenai not to inherit his wife -- must rely on the mechanism of "Iy Efshi b'Takanas Chachamim." RASHI (DH mi'Makom Acher) and RABEINU CHANANEL (cited by the Tosfos Rid) write clearly that Rav Kahana indeed maintains that a Tenai would not work to remove one's rights to his wife's Yerushah if that Yerushah had been mid'Oraisa. He maintains that one may remove his rights to his wife's Yerushah only because that Yerushah is mid'Rabanan, and "Iy Efshi b'Takanas Chachamim" works for a Takanah d'Rabanan. Why, though, does Rav Kahana maintain that a Tenai does not work (as REBBI AKIVA EIGER asks on Rashi)?
The answer seems to be that both Rav Kahana and Rava are explaining how one can relinquish privileges after the Kinyan of Nisu'in has already been made. Since the Nisu'in has already taken effect, one cannot make a Tenai. A Tenai may be made to alter the way the Kinyan takes effect only prior to the time that the Kinyan takes effect. Once it has already taken effect and the man and woman already have certain privileges as a result of the Nisu'in, the only way to remove those privileges is by saying "Iy Efshi b'Takanas Chachamim."
The Gemara asks that a person should be able to remove himself from the right to receive the Peiros of his wife's property even after the Nisu'in takes effect, since "Iy Efshi" (or "Siluk" -- "removal") works even after the Kinyan takes effect. The Gemara answers that in the case of Peiros, "Iy Efshi" will not work because "his acquisition is like hers" ("Yado k'Yadah"). This means that the husband not only has the rights to receive the Peiros as they grow, but he is even considered a partner in the ownership of the land itself, for he co-owns the land with his wife (at least as far as benefiting from its Peiros are concerned). He owns the land with regard to what it produces. Since he is an owner, he cannot remove himself from the ownership of the property through "Siluk" (rather, he must give it away as a gift in order to relinquish his ownership of it).
In summary, both the concept of Tenai and "Iy Efshi" ("Siluk") may be used to relinquish one's rights before the Kinyan (which gives the person those rights to the item) takes effect. After the Kinyan takes effect, if the item has not yet entered the world and the person has only the rights to receive it but not full ownership of the item, he may remove himself from the rights to the item before they come ("Siluk"). If the Kinyan has taken effect, and he also already has full ownership of the item to which the Kinyan entitles him (i.e. it already exists), he may remove himself from its ownership only by giving it away as a gift.
According to Tosfos, the cases of relinquishing rights to the Peiros of the wife's property (in the Mishnah), of inheriting the wife's property (Rav Kahana), and of relinquishing rights to Mezonos (Rava) are all cases of "Siluk," or relinquishing one's rights to receive what he is entitled to, after the Kinyan has taken effect but before the item comes into the world.
(b) The RASHBA understands that the case in which a man forgoes his rights to his wife's Yerushah (the case of Rav Kahana) involves a Tenai and not just a "Siluk." The Rashba writes that one may remove himself from receiving the Yerushah only before the Nisu'in, but when he does so he may remove himself even from a Yerushah d'Oraisa since his removal works with the mechanism of a Tenai and not with the mechanism of "Iy Efshi b'Takanas Chachamim."
According to the Rashba, why does Rava mention that it is the mechanism of "Iy Efshi b'Takanas Chachamim" which allows the woman to relinquish her rights to receive Mezonos? She should be able to use a Tenai, just as the man may relinquish his rights to his wife's Yerushah with a Tenai! The answer is (as mentioned above in the name of Tosfos) that Rava is discussing how a woman may forgo her rights after the Nisu'in, at which point it is too late to do so with a Tenai.
The Rashba may agree with Tosfos that in the case of the Mishnah, the husband forgoes his rights to the Peiros through "Siluk" and not through a Tenai, since he does not use the proper wording for a Tenai.
In summary, according to the Rashba, the husband relinquishes his rights to the Peiros, and the woman relinquishes her rights to Mezonos, through "Siluk," by saying "Iy Efshi b'Takanas Chachamim," as Tosfos explains. The case of Rav Kahana, however, in which the husband declines the rights to his wife's Yerushah, involves the implementation of a Tenai, which is effective even in avoiding a Yerushah d'Oraisa.
(c) RASHI (DH mi'Makom Acher), however, equates the case of Rav Kahana, in which the husband wants to avoid receiving his wife's Yerushah, with the case of Rava, in which the wife wants to avoid receiving Mezonos. Rashi understands that both cases work through the same mechanism. However, it does not seem that Rashi agrees with Tosfos that they work through "Siluk," because Rashi (56a, DH d'Rabanan, and 56b, DH Mai Kosev) writes that even in the case of the Mishnah the husband loses the rights to the Peiros through a Tenai and not just through saying "Iy Efshi" (or "Siluk").
It seems that Rashi maintains that there is no way to remove one's rights to an object through "Siluk" without using a Tenai; there is no independent mechanism of "Siluk." The only way to relinquish the rights to something which one is entitled to receive is by specifying a Tenai before he receives those rights.
Why, then, does Rava mention the logic of "Iy Efshi b'Takanas Chachamim"? A Tenai should work even to relinquish rights that the Torah entitles a person to receive! It seems that the Gemara is giving a reason why one's Tenai works to annul a Takanah d'Rabanan, even according to the opinion (of Raban Shimon ben Gamliel in the Mishnah) that a Tenai cannot annul the rights to receive something that one is entitled to receive mid'Oraisa. The reason is that since the Rabanan instituted this Takanah only for the person's own benefit, they did not apply the Takanah when he has no interest in receiving that benefit.
Why does Rav Kahana need to say that one may make a Tenai not to receive his wife's Yerushah only because of "Iy Efshi" (i.e. the Yerushah is mid'Rabanan), according to Rashi? Does Rav Kahana maintain that when one makes a Tenai that is "Masneh Al Mah she'Kasuv ba'Torah" the Tenai is null and void? The Halachah, however, is that the Tenai is valid! (This is the question of Rebbi Akiva Eiger, as cited in answer (a) above.)
The answer may be that if a man inherits his wife mid'Oraisa, her Yerushah is not a privilege that he receives directly because of the Kinyan of Nisu'in. Rather, when a man and woman marry, they became related to each other ("She'er," see Bamidbar 27:11). He receives her Yerushah as a relative. Accordingly, no Tenai that he makes in the Kinyan of Nisu'in can limit his rights to the Yerushah, because the rights to the Yerushah come not from the Kinyan of Nisu'in but from the change in their relationship as a result of the Nisu'in. Tena'im cannot be made in such things as a change in relationship, since that change is not something which the husband brings about directly. (This is essentially the reason why Tena'im cannot be made in the type of Kinyan which a person cannot accomplish through a Shali'ach; see Kesuvos 74a.)
In summary, Rashi maintains that all three cases work through the mechanism of Tenai and not "Siluk." (M. KORNFELD)
According to Rashi, however, how does "Iy Efshi b'Takanas Chachamim" work in the case of a woman who forgoes her rights to receive Mezonos? She is attempting to relinquish those rights after the Nisu'in has been performed, when those rights have already taken effect. Her Tenai must be made before the Kinyan that creates the husband's obligation takes effect!
The answer is that Rashi maintains that the Takanas Chachamim was that the woman receives Mezonos from her husband in return for giving her earnings to him. Therefore, each day of earnings which she produces and gives to her husband obligates him anew to give her Mezonos in return. Accordingly, before she works and produces earnings for a certain day, she may make a Tenai and say that she wants to keep her earnings for herself and not receive Mezonos in exchange. Since her Tenai is made before the husband's obligation to give her Mezonos takes effect, her Tenai is valid.
The Gemara considers the possibility that such a Tenai can also be made to remove the husband's rights to the Peiros, even when he makes the Tenai after the Nisu'in. Since the Peiros are given to him in return for the obligation to redeem her, one might think that he receives each day's Peiros in return for the obligation to redeem her if she is captured on that day. Therefore, before the Peiros of that day grow he may say that he wants to be obligated to redeem her even without receiving Peiros in return. His statement will be like a Tenai made before the rights to receive the Peiros were granted to him.
The Gemara rejects this possibility, saying that the obligation to redeem her and the rights to receive the Peiros in return for that obligation all take effect at the time of the Nisu'in, when he becomes a partner with her in the ownership of the field. Hence, he cannot relinquish the rights afterwards.
Tosfos and the other Rishonim -- who understand that "Iy Efshi" is a removal of oneself from an entitlement ("Siluk") and not a Tenai -- may have learned that the obligation of Mezonos, too, comes at the time of the Nisu'in, and afterwards she cannot remove herself from those rights through a Tenai but only through "Siluk." (See Tosfos 47b, DH Zimnin, who discusses exactly when the Chiyuv of Mezonos takes effect.)
3) JOINT OWNERSHIP
OPINIONS: The Gemara asks whether the wording of "Din u'Devarim Ein Li..." which a person says in order to remove himself from receiving property is effective when it is accompanied by a Kinyan (that is, a Kinyan Chalifin). Do we assume that the person is strengthening his statement by making the Kinyan on the words that he stated when he said that he has no claim to the property (and since the statement is meaningless when he already owns the property, the Kinyan is also meaningless), or do we assume that the Kinyan was made not on his statement, but in order to effect a direct transfer of ownership through a Kinyan?
What case of "Din u'Devarim" is the Gemara discussing?
(a) RASHI explains that when the Gemara asks on what the person made the Kinyan, the Gemara is referring to the case discussed in the Beraisa -- a field owned by two partners, and one said to the other "Din u'Devarim Ein Li b'Sadeh Zu" ("I want nothing to do with this field").
(b) TOSFOS rejects Rashi's explanation. Tosfos asserts that when one partner says to the other, "Din u'Devarim Ein Li...," he is not expressing any intent to give the field to his partner, but rather the intent to make it Hefker, ownerless. Since his intention is to make it ownerless, how could the Kinyan that he made be construed as being an act of transferring ownership of the field to his partner? The words that he said carry no implication of a transfer of ownership!
Instead, Tosfos explains that the Gemara refers to a case in which a husband says to his wife after the Nisu'in that he does not want to inherit her property -- "Din u'Devarim Ein Li..." (unlike the Mishnah, which is discussing a case in which he said it before Nisu'in). In such a case, since the woman owns the actual body of the field ("Guf"), when the husband says "I am removing my rights to receive the field" he implies that since he is removing his rights to the field's Peiros her ownership of the field will extend to the Peiros as well. Thus, if a Kinyan is made, the Kinyan can work to transfer to her the rights to the Peiros.
It is clear why Rashi does not explain like Tosfos. The Gemara says that the Kinyan that the person makes might take effect on the "body of the field." This implies that the person who says "Din u'Devarim Ein Li..." already has ownership in the body of the field and not just the Peiros. Accordingly, the Gemara must be referring to a case of a normal partnership in which two people own a field, and not to a case of a husband and a wife in which the wife owns the body of the field and the husband has the rights to the Peiros.
How, though, does Rashi answer the question of Tosfos? In the case of two partners who own a field together and one says "Din u'Devarim Ein Li...," where is there an implied transfer of ownership? His statement seems to be nothing more than an attempt to remove himself from his share in the field!
It seems that there is a fundamental dispute between Rashi and Tosfos about the essential nature of a partnership ("Shutfus"). Tosfos maintains that in a partnership, each person owns only half of the property. If one person makes his half Hefker, ownerless, anyone may come and make a Kinyan on it and acquire that half. There is no reason for it to belong to the other partner more than to anyone else.
Rashi, however, apparently maintains that when a field is owned by a partnership, each of the partners actually has rights to the full ownership of the entire field. The only thing which prevents each partner's ownership from taking over the entire field is the ownership which the other partner has in the field, as the RAN explains in Nedarim (45b). Therefore, if one partner makes his share in the field Hefker, the ownership of the other partner automatically extends to the other half of the field as well, and no one else can take it. Accordingly, when one partner says "Din u'Devarim Ein Li...," he indeed implies that he wants the other partner to acquire the entire field.
This dispute might be the root of another Machlokes between Rashi and Tosfos. In Gitin (47b), Rashi (DH Tevel) writes that when a field is jointly owned by partners, each and every grain that is produced is owned equally by each partner. Tosfos, on the other hand, writes that somewhere in the field each partner has his own portion, which is fifty percent of the grain; any specific grain, however, may belong entirely to one of the partners.
Rashi maintains that each person has the rights to the full ownership of the entire field, and therefore they have equal rights to everything which grows anywhere in the field. Tosfos, who says that each partner owns only half of the land somewhere in the field, maintains that since it is not known where each person's portion is located, it is also not known which grain belongs to which partner.

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