OPINIONS: The Mishnah teaches that Shamai and Hillel argue about the status of a woman who saw Dam Nidah. Shamai says that she is considered Tamei only from the actual moment at which she saw the blood, and we do not assume that the blood was present in the Bayis ha'Chitzon before she noticed it (see RASHI DH Shamai Omer). Consequently, all of the food that she previously prepared is still considered Tahor. Hillel argues and says that the woman is considered to be Tamei retroactively (with regard to Tum'ah and Taharah, but not with regard to being forbidden to her husband) from the last time she had a clean Bedikah.

What is the reasoning behind their argument? The Gemara first explains the opinion of Shamai. Shamai reasons that since the woman was Tahor until now, we assume that she is Tahor until the moment she saw Dam Nidah. The Chazakah that she was Tahor overrides the doubt that perhaps there was Dam before she noticed it.

There are different opinions regarding the text of the Gemara's explanation of Hillel's reasoning.

(a) The text of our Gemara is that of RASHI (DH Kegon, and 2b, DH Keivan). Rashi understands that Hillel objects to Shamai's logic, claiming that the logic of a Chazakah is appropriate only when we there is no good reason to assume that the person in question will become Tamei. In such a case we resolve the doubt based on the Chazakah -- a person or object which we know to be Tahor continues to be Tahor until proven otherwise. However, we cannot use this logic for a woman whose body functions in a manner such that she is sometimes Tamei and sometimes Tahor. Such a person does not have a Chazakah of being Tahor until proven otherwise.

(b) Rashi mentions that according to one Girsa in the Gemara, the Gemara adds that Hillel says that a person continues to be Tahor until proven otherwise only in a case of "Safek Naga" -- "there is a doubt whether or not the person touched" something Tamei. This text apparently refers to the Halachah that if a person has a doubt regarding Tum'ah in Reshus ha'Rabim -- "Safek Tum'ah b'Reshus ha'Rabim" -- the Halachah is that he is Tahor.

Rashi rejects this text as erroneous. Hillel is clearly saying that Nidah is not a case in which we apply the Halachic principle that one continues to be Tahor until proven otherwise. Therefore, it is incorrect to say that we do apply the Chazakah in a case of Safek Tum'ah b'Reshus ha'Rabim. The reason why a Safek Tum'ah b'Reshus ha'Rabim is Tahor is because it is learned from Sotah (see Chulin 9b), and it is not based on the logic of Chazakah. Therefore, Hillel certainly is not referring to the principle of Safek Tum'ah b'Reshus ha'Rabim.

TOSFOS (DH v'Hillel), however, apparently keeps this text. He explains that we learn from Sotah one aspect of Safek Tum'ah b'Reshus ha'Rabim. The case of whether or not a woman has committed adultery is similar to a case of a Safek Tum'ah in Reshus ha'Yachid (in a private domain), which we learn is Tamei, unlike the case of Safek Tum'ah b'Reshus ha'Rabim, which is unlike the case of Sotah and therefore Tahor. In the case of Sotah, we are unsure if the woman became Tamei (committed adultery) at all. This is comparable to having one object in question and being unsure whether it became Tamei at all. Tosfos admits that in such a case, we learn the law of Safek Tum'ah from Sotah, and not from the principle of a Chazakah (that one is considered Tahor until proven otherwise). However, what is the Halachah in a case in which there are two objects and one definitely became Tamei, but we are unsure which one became Tamei? If this Safek arises in Reshus ha'Rabim, can we say that both items are Tahor? Tosfos says that this is not the Halachah. Rather, this case is worse than the case of Safek Tum'ah that we learn from Sotah, because in this case there is definitely a Tamei object among the two objects. Hillel is saying that the principle that an item is Tahor until proven otherwise tells us that these objects are Tahor (when the question about each one is asked separately; see Pesachim 10a), because we are unsure which of the two items was touched by the Tamei object.

However, if this is true, then why do we need to learn the law of Safek Tum'ah b'Reshus ha'Rabim from Sotah? If -- when two objects are in question and one is definitely Tamei -- we apply the principle that something is Tahor in Reshus ha'Rabim until proven otherwise, then why do we not apply this principle when one object is in question and it did not necessarily become Tamei? What special law do we learn from Sotah?

Tosfos answers that from Sotah we learn a new law. Even if the item did not have a previously-known status of being Tahor, if the Safek regarding its status arose in Reshus ha'Rabim, then the item is still Tahor. This is also the opinion of Tosfos in Chulin (9b, DH Hasam).

(c) TOSFOS in Avodah Zarah (37b, DH Ha Hilchesa) and in Sotah (28b, DH mi'Kan) apparently keep this text of our Gemara, and learn that it is true in its straightforward understanding. The Halachah that Safek Tum'ah b'Reshus ha'Rabim is always Tahor is known from the principle of Chazakah, that something continues to be Tahor until proven otherwise.

How can Tosfos say this? The Gemara in Chulin (9b) clearly says that this is learned from Sotah, and not from the principle of Chazakah!

The answer is that the Gemara is discussing two cases: one of Safek Tum'ah b'Reshus ha'Rabim, and one of Safek Tum'ah b'Reshus ha'Yachid. The Gemara explains the difference between the two by saying that we learn that a Safek Tum'ah in Reshus ha'Yachid is Tamei from Sotah. Rashi and Tosfos here in Nidah understand that this implies that a Safek Tum'ah in Reshus ha'Rabim, which is unlike Sotah, is Tahor. Tosfos in Avodah Zarah says that this inference is not correct. Rather, the Gemara was unsure about why a Safek in Reshus ha'Yachid should be Tamei, but it understood, based on the principle of Chazakah, why Safek Tum'ah in Reshus ha'Rabim is Tahor. (See KEHILOS YAKOV #61 regarding how these opinions understand cases of Safek Tum'ah in Reshus ha'Rabim when the object has no Chazakah of having been Tahor until now.) (Y. MONTROSE)

QUESTION: The Gemara discusses two cases in which it is not clear when a specific change occurred. The first case is that of a Mikvah that originally contained forty Se'ah of water and was found to be lacking after a person immersed in it. The second case is that of a barrel that originally contained wine and was found to be vinegar after it was declared as Terumah for other wine of Tevel. In the case of the Mikvah, the person who immersed there remains Tamei. In the case of the barrel, the wine of Tevel is considered to be Safek Tevel, because of the doubt that perhaps the wine in the barrel became vinegar before it was declared as Terumah.

The Gemara discusses why, in the case of the Mikvah, the person is certainly Tamei, while in the case of the barrel there is a doubt whether the Terumah takes effect. The Gemara explains that the two statements were made by different Tana'im. The ruling regarding the Mikvah was said by the Rabanan, who maintain that the person who immersed in the Mikvah is unquestionably Tamei, because they maintain that the Chezkas Tum'ah of the person, combined with the fact that the Mikvah is now lacking, tells us that he is still certainly Tamei. The ruling regarding the barrel of wine, in contrast, was said by Rebbi Shimon, who maintains that in the case of the Mikvah the person is only Safek Tamei. Similarly, in the case of the barrel of wine that became vinegar, the barrel of Tevel is Safek Tevel.

The RAMBAM (Hilchos Terumos 5:24) rules like Rebbi Shimon and says that the wine in the barrel is Safek Tevel. However, in the case of the Mikvah, the Rambam (Hilchos Mikva'os 10:6) rules like the Rabanan and says that the person who immersed is certainly Tamei! How can the Rambam rule like both Rebbi Shimon and the Rabanan, when the Gemara here considers their opinions to be mutually exclusive? (KESEF MISHNEH)

ANSWER: The PRI CHADASH (Mayim Chayim, Gitin 31b, as cited by the CHOCHMAS BETZALEL) explains that the Mishnah that discusses the barrel of wine that became vinegar adds a qualification regarding the status of the wine: "For three days, there is no doubt as to the status of the wine." As RASHI (DH Kol) explains, the Amora'im (in Bava Basra 96a) argue what this means. Rebbi Yochanan understands that it means that for the first three days after the barrel was last checked and found to contain wine, we assume that the wine did not yet spoil. The question regarding its status begins only after those three days have passed. Rebbi Yehoshua ben Levi explains that for the last three days before the barrel was found to contain vinegar, we assume that the barrel certainly contained vinegar. The doubt regarding its status applies to the days prior to the three days before it was found to be vinegar.

The Pri Chadash explains that when the Gemara here asks that the ruling in the case of the Mikvah contradicts the ruling in the case of the barrel, and it answers that the Beraisa that discusses the case of the barrel follows the view of Rebbi Shimon, the Gemara understands the ruling of the Beraisa in the way that Rebbi Yehoshua ben Levi understands it. That is, when the Beraisa says that "for three days, there is no doubt" about the status of the contents of the barrel, it means that for the last three days (before the contents were checked and found to contain vinegar), the contents are considered to have been vinegar beyond a doubt. The doubt about the contents of the barrel applies only to the contents before the last three days (even during the first three days after it was last checked and found to be wine). Such a case is exactly the same as the case of the lacking Mikvah. Therefore, the Gemara answers that the case of the barrel must be following the view of Rebbi Shimon.

However, we rule like Rebbi Yochanan, who says that the first three days after the wine was last checked and found to be wine, there is no doubt about the contents of the barrel. The doubt applies only after three days have passed since the last time the wine was checked. According to Rebbi Yochanan, there is no contradiction between the case of the Mikvah and the case of the barrel. Since, in the case of the barrel, there is no doubt for the first three days after it was last found to be wine, even though it is now vinegar, the evidence is not strong enough to assume that the wine, at any point before it was found to be vinegar, was definitely vinegar (as is the case with regard to the Mikvah, where we say that it definitely was lacking when the person immersed in it). Rather, the barrel's status at that time (before it was found to be vinegar) remains a doubt, even according to the Rabanan.

Accordingly, the Rambam, who rules like Rebbi Yochanan's understanding of the Beraisa, says that in the case of the Mikvah, the person is definitely Tamei, while in the case of the barrel, the wine in the other barrel is Safek Tevel.