Question (Part 1): In a case in Chezkas ha'Batim (Bava Basra, 31a & 31b) where two people bring witnesses to substantiate their claim that they had made a three-year Chazakah, but where one of the pairs of witnesses also substantiated one of the claims that the field had belonged to his father, Rav Nachman rules that the two conflicting Chazakos cancel each other, and that we place the land in the possession of the claimant who says that it belonged to his father. Rava however, maintains that since the two testimonies clash, they are both negated.

Question (Part 2): Seeing as here, Rava holds that witnesses only become Pasul with regard to future testimonies, what difference does contradiction make? There too, Rava ought to have said that the testimony is negated only as regards the actual Chazakah, but as far as the testimony regarding the father is concerned, which took place before the contradtion was declared, it ought to be accepted (like Rav Nachman rules).

Question (Part 3): Moreover, seeing now that Rava in our Sugya, regarding witnesses who become Huzam on their testimony on the Shechitah, but not on that of the actual theft, rules that whichever point the witnesses are Huzam, they are Huzam, and whichever point they are not, they are not, how much more ought he to say it there, with regard to Hakchashah?

Suggested Answer: Perhaps we can answer that the Gemara in Chezkas ha'Batim is speaking where the Hakchashah took place 'Toch K'dei Dibur of the first witnesses?

Refutation: It is clear however, from the Gemara in 'Merubeh', Bava Kama, 72b & 73a, regarding Tevichah and Mechirah, that as far as Rava is concerned, the witnesses are not disqualified even if it is 'Toch K'dei Dibir' of the first witnesses.

Answer: The reason that Rava is strict there is, because both sets of testimony concern the ownership of the land, rendering them one testimony (in the manner that the Gemara itself differentiates there); whereas here, even though the witnesses are established as liars regarding Shechitah, they were not established liars on the theft.

Clarification: The Chidush appears to be the fact that we invalidate the first witnesses.

Question: The Gemara there (in Bava Basra, 31b) asks that Rava perhaps holds like R. Chisda, who maintains that we cannot accept false witnesses, and that both pairs are therefore Pasul, even if they merely contradict each other. That being the case, what is the Chidush here, if by Hazamah, we disqualify even the first witnesses?

Answer #1: That when the Gemara there establishes Rava like Rav Chisda, that is only according to the opinion here that invalidates them only on account of the loss of the purchasers (see Tosfos ha'Rosh).

Answer #2: Others explain that the Chidush here is (not that the first witnesses are Pasul, but) that the second ones are Kasher, even though we ought to have declared them Pasul, like all cases of two pairs of contradictory witnesses; and since there is a Chidush here regarding their leniency, we cannot learn from them the stringency by the Pasul witnesses, to extend the P'sul retroactively.

Precedent: A similar format occurs in Perek Kol ha'Basar (Chulin, 99), where the Gemara declines to learn the Chumra of 'Ta'am ke'Ikar' (that 'taste renders Asur just like the actual Isur does') from 'Basar be'Chalav', because there is a Chidush in the aspect of its Heter (since soaking meat all day in milk does not render it Asur, whereas cooking them together even for a short time does.

Question #1: Rabeinu Tam asks that, firstly, what does the Gemara mean when it says that if two witnesses testified against one of the witnessses, and two witnesses testified against the other witnes, there is no Chidush? What about the principle that 'Two is like a hundred'?

Question #2: Secondly, what does it mean when, in the second answer, the Gemara says 'de'Paslinhu be'Gazlenusa'. That is not similar to the case in hand, which is speaking about Hazamah, and one can only draw a distinction in a way that is similar to the Machlokes?

Question #3: And thirdly, seeing as, having said 'Two against one, and two against one', they are clearly talking about two Eidim Zom'min, why did the Gemara introduce the case as 'Eid Zomem' and not 'Eidim Zom'min'.

Answer (Part 1): Rabeinu Tam therefore changes the text to 'that two Eidim testified against one', period; where only one of the witnesses became a Zomem, which explains why the Gemara begins with the Lashon 'Eid Zomem' (in the singular).

Answer (Part 2): It also explains why two Mazimin are better than one, and why it is no Chidush.

Answer (Part 3): And he also reads in the second answer 'and he disqualified him as being a Gazlan, meaning that one of the witnesses is disqualified by being declared a Gazlan, and the other one, by being Huzam - and this is slightly similar to their Machlokes.

Question: Why does Abaye not query Rava from the Mihnah in Perek Kol ha'Nishba'in (Shevu'os, Daf 44b), which states that if the defendant is suspect on swearing falsely, then the claimant swears and takes` - and the Gemara explains there that this speaks even if he is suspect on swearing a Shevu'as Shav. So we see that in order to become Pasul, one need not be a Rasha de'Chamas, but that if one is suspect on a Shevuas Shav (which makes him Ra la'Shamayim), that is sufficient to make him Pasul on a Shevu'as Mamon (Ra la'Beri'os)?

Answer (Part 1): The case there is not comparable to our Sugya; since there the Shevu'ah that he made renders him Ra la'Shamayim, and now that he has denied his friend Mamon, he becomes also a Ra la'Beri'os. Consequently, fear of making a false oath will not deter him from swearing.

Answer (Part 2): ... whereas in our case (of Eidus), even though he is Ra la'Shamayim due to the Shevu'as Shav, we do not suspect him of testifying falsely to become Ra la'Beri'os - See further, Tosfos Shevu'os, 46b DH 'va'Afilu'.

Explanation #1: ' ... and their sons and their sons-in-law' refers to the relatives who are listed in the Mishnah specifically, such as 'the brother of his father and mother', but not to those relations that are learned from an inference, such as his own sons and sons-in-law, who are not Pasul from testifying for the others - unless they are also relatives of those that are listed.

Proof: And as proof of this, 'his son' is Kasher to testify for his 'father's brother', according to the Tana of the Mishnah, since he falls under the category of 'the third to the first', as the Gemara explains.

Question: Rashi asks why the Tana lists 'step-son', which we already know from 'mother's husband'?

Implied answer: Perhaps it is because of the word 'alone' (which precludes 'their sons and their sons-in-law).

Refutation: That too, is obvious, seeing as we have already learned that 'sons and sons-in-law' does not pertain to those relations that we learn from inferences (including 'son-in-law' according to the current Kashya).

Answer: The Tana is not troubled by the question, since there are anyway three relatives that we can learn by sway of inference, yet the Tana mentions them specifically (such as 'father's brother', which we already know from 'his brother and his son' [see next Tosfos]).

Question: Why does the Tana not also list 'his wife's brother's son', like it mentions the others?

Implied Question and Answer: The reason that the Mishnah does not mention 'son-in-law' is because we can learn it from a 'Kal ve'Chomer' from 'Chasneihem' (how much more so 'son-in-law' to his 'father-in-law').

Conclusion: But 'his wife's brother's son' remains a Kashya?

Explanation #2: It therefore seems that the Tana needs to mention all the cases, either intrinsically or because of 'their sons and sons-in-law'.

Question: In that case, the Kashya we asked earlier from 'stepson' returns?

Answer: The Tana does indeed mention it because of the word 'alone, and his son or his son-in-law' (as we suggested earlier).

Implied Question: Even though 'their sons and their sons-in-law' does not pertain to those cases that we learn from an inference (as we explained there) ...

Answer: ... nevertheless, by 'stepson' it is necessary. This is because we might otherwise have thought that since a stepson is like a son, and a son's son is Pasul, the son of a stepson is Pasul, too. So the Mishnah needs to teach us that he is not.

Implied Question: But what can we say according to Mar bar Rav Ashi who validates 'the father's father' - which is equivalent to 'the son's son'?

Answer (Part 1): Presumably, he learns it from here (from 'stepson').

Answer (Part 2): On the other hand, there is no need to mention the 'wife's brother's son', since we already know that from an inference (as we explained earlier).

Implied Question: And if it is to teach us that only he is Pasul, but not his 'son or his son-in-law' (like we learned by 'stepson') ...

Answer #1: That is obvious, for why would we have though otherwise?

Answer #2: And besides, there is no reason why a 'wife's brother's son' should be any different than 'a brother's son', whose 'son and son-in-law' is Kasher. This is because it says by all the cases 'and their sons', implying that the 'sons of their sons' are permitted.

Explanation #1: Meaning, but not his son and not his son-in-law.

Question: Rashi asks why the Tana needs to mention step-son at all, seeing as it is included in 'his mother's husband'?

Suggested Answer: And we cannot answer that it mentions it because of the clause 'only', implying us that his son is permitted.

Refutation: ... since that too, is obvious, seeing as we have already explained that 'their sons and sons-in-law' is confined to those relations that are written explicitly, but not to those that are derived from an inference. Because 'his son' is Kasher to testify for his father's brother, according to the Tana of the Mishnah, since he falls under the category of 'the third to the first', as the Gemara explains.

Answer: Rashi therefore explains that all the cases we can also learn from an inference - such as 'father's brother', which we can learn from 'his brother and his son ... ', yet the Tana inserts them, because it does not bother him to do so (with the exception of 'the son of his wife's brother', which we can learn from 'his father's sister's husband', and 'son-in-law', which we can learn from 'his father-in-law').

Refutation: This is not correct however, because if so, why did the Tana not repeat those cases that we can learn from 'father's sister's husband' and 'father-in-law'?

Explanation #2 (Part 1): We must therefore say that all the cases need to be mentioned - 'father's brother', which intrinsically we may well know from 'brother's son', but which nevertheless needs to be mentioned because of 'son and 'son-in-law' which we cannot learn from an inference. Likewise, 'mother's brother' and 'sister's husband', even though 'their son' we can learn from 'mother's brother' (see Maharsha), nevertheless, they themselves we do not know. And it is coming to teach us that 'a husband is like his wife' in these matters.

Explanation #2 (Part 2): And so it is with regard to all the cases; each one requires mentioning, either intrisically or because of 'their sons and their sons-in-law'.

Comment: This Dibur seems to be [largely] redundant.