1) "DINA D'MALCHUSA DINA" IN THE CASE OF AN INDIVIDUAL KING'S PERSONAL LAW
QUESTION: Rav Huna brei D'Rav Yehoshua says that it is the law of the land ("Dina d'Malchusa") that all property, even "barley [that has been harvested and placed] in the barrel," is considered Meshubad to the taxes of the king, both the land tax and the head tax. Consequently, if a person pays the tax of another person to the king, he is entitled to take even the "barley in the barrel."
Why should Rav Huna brei d'Rav Yehoshua say that such a specific item is Meshubad to the king's taxes? He should say instead that we inquire about this particular king's policies and determine what is Meshubad to his taxes based on his particular policies!
ANSWER: The RAMBAN, RASHBA, and RAN answer that Rav Huna brei d'Rav Yehoshua means that such an object is Meshubad to the taxes in all kingdoms, and therefore it falls within the category of "Dina d'Malchusa Dina." A policy that is unique to only this specific king does not fall under the category of "Dina d'Malchusa Dina" (for the rule is not "Dina d'Melech Dina," but rather "Dina d'Malchusa Dina").
(The RAMBAM (Hilchos Gezeilah 5:13-14), however, rules that any law that the king establishes for all of the constituents of his kingdom is considered "Dina d'Malchusa" and is binding. Only when the king takes property with no legal grounds (even under a law that he makes himself) is it not considered "Dina d'Malchusa.")
2) THE PRE-TAX "SHIBUD" OF A KING ON A PERSON'S PROPERTY
QUESTION: The Gemara asks that if, in a certain country, the law is that a person's property is Meshubad to the king until the tax is paid, then the Torah's law that the Bechor receives a double portion of his father's inheritance will never apply, because a Bechor receives a double portion only of property which is actually in his father's possession ("Muchzak") and not of property that will eventually come into his father's possession ("Ra'uy"). The Gemara answers that the law of a Bechor's inheritance will apply when the father paid the tax before he died, and thus the property entered his possession completely.
Why does the Gemara assume that the Shibud of a king on the property of the father makes the property "Ra'uy" and not "Muchzak" with regard to the Bechor's right to inherit it? In all other cases of property that is Meshubad to someone else, the Shibud does not make the property "Ra'uy" and not "Muchzak." For example, in a case where the father's property is Meshubad to the Kesuvah of his wife, or his property is Meshubad to a lender, that property still is considered "Muchzak" and the Bechor receives a double portion of it (see Bava Basra 124a). Why, then, is the Gemara bothered by the Shibud that a king has on a person's property?
ANSWER: TOSFOS (DH Im Ken) answers that the Shibud of a king is much stronger than the Shibud of a wife's Kesuvah or of a lender. In the case of a Kesuvah or a lender, the property still is in the complete possession of the man and is considered "Muchzak"; if the man's creditors, or former wife, wants to collect that property, then they must initiate a prolonged judicial process (see Background to the Daf to Bava Metzia 35:22) in order to obtain the property. In contrast, a king by law may simply evict the person from his property with no further ado. Therefore, property that is Meshubad to a king is not considered fully in the possession of the owner (and it is "Ra'uy"), whereas property that is Meshubad to a Kesuvah or to a creditor is considered fully in the possession of the owner ("Muchzak"). This also seems to be the explanation of the RASHBAM (DH Im Ken).
The ALIYOS D'RABEINU YONAH adds that the Shibud of a king to a person's property is actually more than just a Shibud. As long as the taxes have not yet been paid, the king actually owns the property (and he may sell it to whomever he wishes). In contrast, the Shibud of a creditor to the borrower's property is merely a lien; the borrower still fully owns his property. The RAMBAN explains further that the Shibud of a creditor merely obligates the borrower, or his heirs, to pay back the loan or to give the property to the creditor as repayment. The Shibud of a king actually places the property into the king's possession until the taxes are paid. Proof for this difference, the Ramban points out, is that the creditor is not entitled to sell the property of the borrower that is Meshubad to him, while the king is entitled to sell the property that is Meshubad to him.
3) A VALLEY WITH MULTIPLE FIELDS AND "TUM'AH" IN ONE OF THEM
OPINIONS: Rav Asi says in the name of Rebbi Yochanan (55a) that a boundary fence or a Chatzav tree divides a field of Hefker with regard to a Chazakah (such that one who does an act of Chazakah on one side does not acquire the other side), but not with regard to Pe'ah or Tum'ah. Ravin in the name of Rebbi Yochanan argues and says that they serve as divisions even with regard to Pe'ah and Tum'ah.
The Gemara here explains what relevance a division in a field has to the laws of Tum'ah by quoting the Mishnah in Taharos (6:5). The Mishnah there discusses a case in which a person entered a valley in the wintertime (when people normally do not walk in a valley, and thus the valley is considered a Reshus ha'Yachid), and there was Tum'ah (such as a grave) in one field in the valley, and the person does not know whether he entered that field or not. Rebbi Elazar says that if the doubt is whether he even entered the field that contained the Tum'ah, then he is Tahor, but if he certainly entered the field with the Tum'ah but the doubt is whether he touched the Tum'ah, then he is Tamei. Hence, according to Rebbi Elazar, if something divided the land in the valley into at least two fields, then the person is Tahor. The Chachamim argue and say that the person is Tamei regardless of how many fields there are in the valley, because the rule is that a Safek Tum'ah in a Reshus ha'Yachid is Tamei.
What is the basis of the dispute between Rebbi Elazar and the Chachamim?
(a) The RASHBAM explains that Rebbi Elazar says that the person is Tahor because of a Sfek Sfeika. The first Safek is that perhaps the person did not enter the field that contains the Tum'ah. The second Safek is that even if he did enter the field that contains the Tum'ah, perhaps he did not touch it. The Chachamim, on the other hand, maintain that there is only one Safek: perhaps the person walked until and reached the Tum'ah and stood over it, and perhaps he did not reach it. Since it is a single Safek, the rule is that Safek Tum'ah in Reshus ha'Yachid is Tamei.
(The Acharonim question the Rashbam's explanation (that according to Rebbi Elazar this is a Sfek Sfeika) from certain rules that govern the application of the principle of Sfek Sfeika. See BINAS ADAM (Sfek Sfeika #53), BEIS ME'IR (YD 110:14), SHACH (YD 110:15), as cited by OHEL TORAH.)
(b) TOSFOS cites RASHI in Avodah Zarah (70a) who explains that the Mishnah in Taharos discusses a case of a field full of Tum'ah. The Machlokes between Rebbi Elazar and the Chachamim is as follows. Rebbi Elazar maintains that even though there is only a single Safek, since the Safek is not whether the person touched the Tum'ah but rather whether he entered that field or not, Rebbi Elazar rules that Safek Bi'ah is Tahor. He rules this way because the principle of "Safek Tum'ah in Reshus ha'Yachid is Tamei" is learned from the laws of Sotah. A woman who was warned by her husband not to seclude herself with another man and nevertheless secluded herself is Asurah ("Teme'ah") to her husband even though there is only a doubt whether she sinned or not with the other man. The Torah teaches that a Safek Tum'ah of Sotah in Reshus ha'Yachid is considered Vadai Tamei and thus she is Asurah to her husband. There, in the case of Sotah, the Safek is a Safek Maga -- the Safek is whether the woman "touched" the man or not. The Safek is not a Safek Bi'ah -- a Safek of whether she entered the place or not. Therefore, Rebbi Elazar rules that in a case of a Safek Bi'ah, a Safek of whether or not the person entered a certain place (such as a field containing Tum'ah), the Safek is Tahor even in Reshus ha'Yachid. According to Rashi, Rebbi Elazar says that the person is Tahor not because it is a case of a Sfek Sfeika, but because the type of Safek is not the type to which the rule of Safek Tum'ah in Reshus ha'Yachid applies.
The Chachamim disagree and maintain that since there is only one Safek in this case, even though it is a Safek Bi'ah, the rule of Safek Tum'ah in Reshus ha'Yachid applies and the person is Tamei.
(c) TOSFOS cites RABEINU TAM who questions the explanations of Rashi and the Rashbam. According to both Rashi and the Rashbam, Rebbi Elazar and the Chachamim agree that a Sfek Sfeika in Reshus ha'Yachid is Tahor (the Machlokes is only whether this case is considered one Safek or two Sfeikos (Rashbam), or whether this case is the type of Safek to which the rule of Safek Tum'ah in Reshus ha'Yachid applies (Rashi)). Rabeinu Tam asks that the Mishnah in Taharos seems to contradict this. The Mishnah there (6:4) states that regardless of how many Sfeikos there are in Reshus ha'Yachid, a Safek Tum'ah is still Tamei.
Rabeinu Tam therefore explains that the Machlokes between Rebbi Elazar and the Chachamim is whether a Sfek Sfeika in Reshus ha'Yachid is Tamei or not. The Chachamim maintain that a Sfek Sfeika in Reshus ha'Yachid is Tamei, even when there are multiple Sfeikos. Their reasoning is that, m'Ikar ha'Din, even a single Safek in Reshus ha'Yachid should be Tahor because the person has a Chezkas Tahor: since he was Tahor until now, once the Safek arises his status now is considered the same as his status before the Safek arose (as in all other cases of Safek), and he should be Tahor. However, the laws of Sotah teach that a Chezkas Tahor does not apply in the case of a Safek Tum'ah in Reshus ha'Yachid, but rather the person is deemed Vadai Tamei. Accordingly, it makes no difference whether there is one Safek or multiple Sfeikos -- the law of Sotah that Safek Tum'ah in Reshus ha'Yachid is Tamei overrides the rule of Chezkas Tahor.
Rebbi Elazar maintains that this Chidush (that Safek Tum'ah in Reshus ha'Yachid is Tamei) applies only to the extent that the Torah applies it with regard to Sotah. In the case of Sotah, there is only one Safek, and the Torah teaches that the Safek Tum'ah of a Sotah (in Reshus ha'Yachid) is Vadai Tamei. This is a Chidush, since one would have otherwise determined the status of the woman based on the Chazakah that the Sotah is permitted to her husband. Therefore, this Chidush applies only to a case similar to the case of Sotah -- where there is only a single Safek. Where there is a Sfek Sfeika, though, the normal rule of Chazakah applies, and thus the person is Tahor.