1) A "SFEK SFEIKA" WITH "TUM'AH" IN "RESHUS HA'YACHID"
QUESTION: The Gemara says that in a house of Nochrim, there is a concern that the Nochri residents might have buried a stillborn under the floor of the house. As a result of this possibility, the house is Tamei out of doubt (mi'Safek). If, however, there are weasels in the vicinity, the house is not deemed Tamei, because it is possible that a weasel might have found the corpse and eaten it. The house is not Tamei because there is a Sfek Sfeika: perhaps no corpse was buried in the floor of the house, and even if one was, perhaps a weasel came and removed it.
The Gemara later relates an incident that involved a Kohen who leaned over a pit to peer into it, when there was a possibility that the corpse of a stillborn was in the pit. Since the pit is a place frequented by weasels, the Kohen does not become Tamei, because even if a corpse had been discarded there, it was likely eaten or dragged away by a weasel.
Why does the Gemara assume that the source of Tum'ah is gone merely because of a Sfek Sfeika? The Mishnah in Taharos (6:4) teaches the principle that in every case of doubt with regard to Tum'ah and Taharah in Reshus ha'Yachid, the object or person in question is deemed to be Tamei, even when there is only a small chance that the person or object is actually Tamei (for example, in the case of a Sfek Sfeika of a Sfek Sfeika). Why, in the cases of the Gemara here, were the Rabanan lenient with Tum'ah in Reshus ha'Yachid because of a Sfek Sfeika?
(a) TOSFOS (DH v'Im) answers that it is so common for a weasel to drag away a corpse that it is almost absolutely certain that the weasel took it away or ate it. The house of the Nochri, and the pit over which the Kohen leaned, are deemed Tahor because the Tum'ah is considered to have been certainly removed from the premises, and not merely because of a Sfek Sfeika.
(b) The MAHARAM CHALAVAH explains that in the cases of the Gemara here, the Sfek Sfeika is not the only reason to be lenient with regard to the Tum'ah. Rather, there is another factor involved -- the uncertainty whether there was any Tum'ah present in the first place. A normal Safek or Sfek Sfeika involves a situation in which there definitely was Tum'ah, and the only question is whether it was removed or not. The rule of the Mishnah in Taharos applies in such a case, and the object is deemed Tamei out of doubt. In contrast, in the case of the house of a Nochri, it is not known whether there was a stillborn buried there at all. Similarly, in the case of the Kohen who leans over a pit, it is not known whether there was a stillborn in the pit. In such a case, the general principle that Safek Tum'ah in Reshus ha'Yachid is Tamei does not apply. A Safek Tum'ah in Reshus ha'Yachid is deemed Tamei only when it was known that there was once Tum'ah there and now there is a Sfek Sfeika.
2) THE OBLIGATION TO PERFORM BEDIKAS CHAMETZ WHEN THERE IS A "SFEK SFEIKA"
QUESTION: The Gemara presents a number of Halachos with regard to cases in which a mouse runs off with Chametz and causes doubts to arise as to whether there is Chametz in one's house (and he must perform another Bedikas Chametz) or not.
Why does the Gemara not rule leniently and exempt the owner of the house from Bedikah on the grounds that there is a Sfek Sfeika that Chametz is present? One Safek is that it is not known whether the mouse brought Chametz into the house, and the other Safek is that even if the mouse did bring Chametz into the house, perhaps it ate the Chametz.
(a) TOSFOS (DH Hayinu) explains that in each of the cases of the Gemara, a rodent disappeared with a very large loaf of bread. It is too large for the rodent to finish eating before Pesach arrives. If it was indeed brought into the house, it certainly is still there (and the case is that of a single Safek, and not a Sfek Sfeika).
(b) The BA'AL HA'ME'OR suggests that the Gemara here follows the opinion of Rebbi Zeira (9a), who says that the only type of food that a rodent eats right away is meat. When it finds bread, it always leaves over some for later.
(c) The RA'AVAD explains that at the exact moment that the rodent ran into the house with Chametz, it was known for certain that there was bread in the house. Since at the moment the rodent entered the house it is known for certain that there was Chametz in the house, the owner is obligated to perform Bedikah. Even though the rodent might have eaten it later, the obligation to search the house has already taken effect and is not removed by a doubt that arises later.
(d) The BA'AL HA'ME'OR cites in the name of "Yesh Mefarshim" that only a weasel eats whatever it finds. A mouse, in contrast, always leaves over some food.
3) REPEATING BEDIKAS CHAMETZ WHEN IN DOUBT
QUESTION: The Gemara presents a case in which a doubt arises whether or not there is Chametz in one's home and one must perform another Bedikah. There were nine piles of Matzah and one pile of Chametz. A mouse took one pile and brought it into the house, but it is not known which pile it took into the house. RASHI explains that if the piles were "Kavu'a," then the principle of "k'Mechtzah Al Mechtzah" applies and it is as if there were equal numbers of piles of Matzah and Chametz. The rule of "Safek Isur l'Chumra" requires that one be stringent and perform another Bedikah.
Why does the rule of Safek Isur l'Chumra apply in this case? Bedikas Chametz is only a Chiyuv d'Rabanan! Once a person has done Bitul Chametz and nullified whatever Chametz might be in his possession, the requirement to do Bedikah is only mid'Rabanan. In the case of a Safek d'Rabanan, one may conduct himself leniently, and thus he should not be required to perform another Bedikah.
(a) The BA'AL HA'ME'OR answers that, indeed, when the Gemara rules that this case is a Safek Isur and one must conduct himself stringently, it means that one must perform another Bitul. He does not need to perform another Bedikah. (When the piles are not "Kavu'a," and there is a majority of Matzah piles, one is not required to perform even Bitul again.)
(b) The RA'AVAD (on the Rif) answers that a Safek with regard to Bedikas Chametz differs from any other Safek d'Rabanan. Bedikas Chametz was enacted in order to account for any doubt as to whether or not there is Chametz in one's home. Since the very purpose of Bedikas Chametz is to account for a doubt, the requirement of Bedikah applies even in the case of the Gemara here, where one knows that the mouse took something into the house but he does not know whether the item is Chametz or Matzah. (This is also the explanation of the RAMBAN in Bava Basra 55b.)
Nevertheless, the Gemara gives a number of cases in which the principle of Safek d'Rabanan l'Kula does apply with regard to Bedikas Chametz (for example, the case of two piles, one of Chametz and one of Matzah, and two houses, where one pile was brought into each house; the case where one did a Bedikah but then found some Chametz and is unsure whether or not there is additional Chametz there (see Rashi DH Kol Davar); the case of a doubt whether the mouse went into the house with Chametz or not; in all of these cases, Rashi says that one does not need to perform another Bedikah because Safek d'Rabanan l'Kula). Why, in these cases, is one exempt from Bedikas Chametz, according to the Ra'avad?
The answer is that the requirement to perform Bedikah when there is a Safek applies only when one definitely brought Chametz into his house, or it is a place where Chametz is commonly brought, and now it is not known whether there is still Chametz there. Bedikah is required because we assume that Chametz is still there. Similarly, when it is known that something was brought into the house but there is a doubt whether it is Chametz or Matzah, one must perform Bedikah. In the cases above, the Halachah is Safek d'Rabanan l'Kula. The requirement to do Bedikah does not apply in those cases of Safek, because the Safek is not where the Chametz is or whether it was removed, but whether Chametz was ever brought into the house in the first place. In such a case, the normal principle of Safek d'Rabanan l'Kula applies. (In the case of two piles, one of Chametz and one of Matzah, and two houses into which the piles were brought, even though Chametz definitely went into one of the houses, we are still lenient because of the principle of "Talinan" -- we assume that the Chametz was brought into the non-checked house, which makes it certain that Chametz was not brought into the house that was already checked. Therefore, the Rabanan did not enact that Bedikah be done in such a case.)