ARE WE CONCERNED LEST A WEASEL DRAGGED CHAMETZ?
(Mishnah): We are not concerned lest a weasel dragged Chametz from one house or place [that was not checked] to another house or place [that was checked], for if we would be concerned, we should also be concerned [for dragging] from [a house in] one courtyardto another courtyard, orfrom one city to another city!
(Gemara) Inference: We are not concerned because we did not see it - but if we saw a weasel drag Chametz to another house, we would be concerned and require checking it again.
Question: We should assume that the weasel ate it!
(Mishnah): Dwellings of Nochrim are Temei'im [unless they are checked - Nochrim often bury miscarriages inside];
A Nochri must dwell there for 40 days to require Bedikah (a miscarriage before this is not considered a fetus, it isTahor; we are not so stringent to be concerned that she was pregnant beforehand);
We are concerned even for a Nochri without a wife [lest he had extramarital relations].
One need not check any place a weasel can get to.
Answer #1 (R. Zeira): A weasel does not leave over meat, but it leaves over bread.
Answer #2 (Rava): The cases are totally dissimilar!
Regarding Tum'ah, we do not know if there was Tum'ah there; even if there was, perhaps the weasel ate it;
Here, if we know that it took Chametz, would we say that it [surely] ate it?! There was Vadai (definitely) Chametz, there is a Safek if it was removed - a Safek does not overturn [a Chazakah based on] Vadai!
CAN A SAFEK OVERTURN VADAI?
Question: A Safek can overturn Vadai!
(Beraisa): If a Chaver died leaving a bin full of produce, even if Miru'ach (final processing) was done that day, we assume that he tithed it.
The produce definitely was Tevel (untithed), there is a Safek whether or not it was tithed, nevertheless it is permitted!
Answer #1: No, it definitely was tithed:
(Rav Chanina Chuza'ah): There is a Chazakah that a Chaver does not allow Tevel to leave his jurisdiction [lest he transgress "V'Lifnei Iver Lo Siten Michshol," causing others to sin].
Answer #2: It was not definitely Tevel - perhaps the Chaver did like R. Oshaya:
(R. Oshaya): A person may scheme, and bring produce into his house with the chaff, and his animal [or himself, if he eats casually] may eat without tithing.
Question: A Safek can overturn Vadai!
(Beraisa - R. Yehudah): A case occurred, a slave dropped a Nefel (miscarriage) into a pit. A Kohen stood over it to see its gender [which determines the Tum'ah of the mother - he was unable to see what was there.] Chachamim ruled that he is Tahor, because weasels are often in pits, perhaps they dragged the Nefel away [to a hole from which the Tum'ah will not leave; or, perhaps they ate it] and he was not over it.
There definitely was a Nefel in the pit, and we are unsure if it was dragged away, and we assume that it was!
Answer #1: She dropped something resembling a Nefel into a pit (perhaps it was not Tamei).
Objection: It says that a Kohen looked to see if it was a male or female!
Answer: It means, he looked to see if it was a real Nefel or Ru'ach (a sac of skin full of air); and if it was a Nefel, whether it was male or female.
Answer #2: Since weasels are [normally] found in pits, certainly they dragged it away;
Granted, [if we saw them take Chametz we are concerned lest] they leave over - but surely, they already dragged the Nefel away by the time [the Kohen looked].
WHEN IS A SECOND BEDIKAH REQUIRED?
Question: We are concerned lest weasels drag away remaining Chametz!
(Mishnah): Chametz that one leaves over [after the Bedikah, to eat before the time of Bi'ur] must be put in a covert place, so one will not need to check again [lest weasels dragged it elsewhere].
Answer #1 (Abaye): If one checks on the 13th, we are not concerned - there is much bread around, the weasel does not bother to leave over for another time;
On the 14th, we are concerned [lest the weasel leave over, since bread is scarce].
Objection (Rava): How does the weasel know that today is the 14th, and that no more bread will be baked until evening] - is it a prophet?!
Answer #2 (Rava): Rather, one leaves remaining Chametz in a covert place, lest he see a weasel take it, and he will be obligated to check again.
Support (for Rava - Beraisa): If one wants to eat Chametz after checking, he should leave it in a covert place, lest he will see a weasel take it, and be obligated to check again.
(Rav Mari): This is a decree lest one leave 10 pieces of Chametz and later find only nine (Shulchan Aruch - if it was left where weasels cannot get to it, he need not check again, for surely a person took it).
If there were nine piles of Matzah and one of Chametz, and a weasel took a piece from a pile, and we do not know from which it took, this is like the case of nine stores; if a piece separated from one of the piles and a weasel took it, this is like the Seifa [of the Beraisa]:
(Beraisa): If nine stores in the city sell slaughtered meat and one sells Neveilah, and a man is not sure from which he bought, the meat is forbidden (it is considered an even doubt - see note 10 in Appendix. Rashi - regarding Chametz, another Bedikah is required. Tosfos - surely, also Chametz involoves a Safek mid'Oraisa, i.e. is the piece itself permitted, or must one repeat Bedikah if Bitul was not done. Chidushei. ha'Ran - first, we rule that the piece is forbidden [as if it was Vadai Chametz] - therefore, another Bedikah is required .
If meat is found, we go after the majority (and correspondingly, we assume that it took Matzah).
If there was a pile of Matzah and a pile of Chametz, and a weasel took a piece of Matzah and another weasel took a piece of Chametz, and one entered a house that was checked for Chametz and the other entered an unchecked house, and we do not know which entered which, this is like the case of two boxes:
(Beraisa): If there are two boxes, one of Terumah and one of Chulin, and two Sa'im (measures of grain), one of Terumah and one of Chulin, and one Se'ah fell into each box, both boxes are permitted, because we [are lenient to] say that the Terumah fell into the Terumah and the Chulin into the Chulin.
Question: We cannot learn from Terumah, which is [nowadays] mid'Rabanan, to Chametz, which is mid'Oraisa!
Answer: Also Bedikah is only mid'Rabanan [for one who was Mevatel] - mid'Oraisa, Bitul is sufficient (Tosfos - the Chametz become Hefker; Rashi - Bitul fulfils Tashbisu).