And Rav Dimi, son of Rav Naḥman, son of Rav Yosef, says: This is referring to a case where the litigant accepted one of these people upon himself as one of the judges, in addition to two fit judges. Since the dispute between Rabbi Meir and the Rabbis with regard to a litigant retracting his acceptance of someone who is generally disqualified from judging is stated in the next mishna, why is it stated in this mishna as well?

The Gemara answers: The statements in both mishnayot are necessary. As, had the Mishna taught this dispute only with regard to a litigant who said: My father is trusted to adjudicate for me, or: Your father is trusted to adjudicate for me, one might have reasoned that only in this case did the Rabbis say that he cannot retract his acceptance, because: My father, and: Your father, are fit to judge for the general public. But in a case where a litigant accepts one witness as equivalent to two witnesses, since one witness is someone who is not fit to testify by himself for the general public one might say that the Rabbis concede to Rabbi Meir that he can retract his acceptance. Therefore, it is necessary for the dispute to be stated with regard to the case in this mishna as well.

And conversely, if the Mishna would teach us their dispute only with regard to this case, where a litigant effectively accepted one witness as equivalent to two, one might have reasoned that specifically in this case Rabbi Meir says that he can retract his acceptance. But in that case, where he accepted his father or the father of the other litigant as a judge, one might say that Rabbi Meir concedes to the Rabbis that he cannot retract his acceptance. It is therefore necessary for the mishna to state both disputes.

The Gemara asks: But from the fact that in the former clause the mishna teaches that one litigant can disqualify the judge, in singular, chosen by the other litigant, and in the latter clause the wording is his witnesses, in plural, evidently the mishna teaches this specifically with regard to a case of two witnesses. It is incorrect to emend the text to read witness instead of witnesses.

Rabbi Elazar said: The mishna is referring to a case where the litigant and another person come to disqualify the witnesses, testifying that they are disqualified from bearing witness.

The Gemara asks: Is it in his power to testify that the witnesses of the other litigant are disqualified from bearing witness? His testimony is tainted by a conflict of interest; how can the court accept it?

Rav Aḥa, son of Rav Ika, said: The mishna is referring to a case where he raised a challenge against the witness’s fitness to testify, which cannot be disregarded due to his conflict of interest.

The Gemara asks: A challenge over which matter? If we say that he raises a challenge by testifying that the witness is guilty of theft or some other transgression, is it in his power to testify to that effect? His testimony is tainted by a conflict of interest.

Rather, it is a challenge over a family flaw. The litigant testifies that the witness’s lineage prevents him from testifying, as he is from a family of Canaanite slaves. Rabbi Meir holds that the litigant’s testimony is accepted, as these witnesses, the litigant and the witness who testifies with him, are testifying about the family of the witness, and the witness is disqualified indirectly. The litigant is therefore not disqualified from giving this testimony due to his conflict of interest. And the Rabbis hold that since his testimony is ultimately tainted by a conflict of interest, it is not accepted.

When Rav Dimi came from Eretz Yisrael, he said that Rabbi Yoḥanan says: The dispute is with regard to a case in which one of the litigants claims that there are two sets of witnesses who can testify on his behalf, and the other litigant responds that one of the sets of witnesses is disqualified. In this case, the second litigant’s claim is not tainted by a conflict of interest, as there is another set of witnesses who can testify against him in any event.

Rabbi Meir maintains that the litigant cannot give this testimony, as Rabbi Meir holds that a litigant who claims in court to have a certain number of witnesses ready to testify on his behalf is required to substantiate that they exist. Therefore, there is no concern that the other set of witnesses will not be brought to court, causing that litigant to lose the case due to the disqualification of the first set. And the Rabbis hold that one is not required to substantiate the existence of witnesses he claims to have. As the disqualification of the first set of witnesses can cause the first litigant to lose the case, the second litigant is consequently unable to disqualify that first set, due to his conflict of interest. But in a case of one set of witnesses, everyone agrees that a litigant cannot disqualify them, due to his conflict of interest.

Rav Dimi continued: Rav Ami and Rav Asi said before Rabbi Yoḥanan: If there is only one set of witnesses there, what is the halakha?

The Gemara interrupts: If there is only one set of witnesses there, what is the dilemma? But didn’t you already say: But in a case of one set of witnesses, everyone agrees that a litigant cannot disqualify them? Rather, the question should be understood as follows: According to Rabbi Meir, who holds that a litigant can disqualify one of the other litigant’s two sets of witnesses, if the second set is ultimately found to be related to one of the litigants or to each other, or is disqualified from bearing witness for other reasons, what is the halakha? Can the litigant whose witnesses were disqualified then claim that the other litigant was not capable of disqualifying the first set, as it turned out that they were the only witnesses who would be testifying against him?

Rabbi Yoḥanan said to them: The first pair of witnesses, i.e., the second litigant, who disqualified the other litigant’s first set of witnesses, already testified. Since his testimony was valid at the time it cannot be disqualified afterward. Some say this statement in the name of a different amora: Rav Ashi says: The first pair of witnesses already testified.

The Gemara asks: Shall we say that Rabbi Meir and the Rabbis disagree with regard to the issue that is the subject of the dispute between Rabbi Yehuda HaNasi and Rabban Shimon ben Gamliel?

As it is taught in a baraita: With regard to one who comes to court to be judged concerning a claim against land that is in his possession, if in order to support his claim of ownership he comes to court both with a deed of purchase proving that the land is his and with a claim of presumptive ownership of the land stating that it had been in his possession for the past three years, which would render the deed superfluous, in this case his claim is judged on the basis of the deed. The court examines whether or not the deed is valid. This is the statement of Rabbi Yehuda HaNasi. Rabban Shimon ben Gamliel says: His claim is judged on the basis of his presumptive ownership.

And we discussed this dispute, asking: Can Rabban Shimon ben Gamliel possibly mean that the defendant’s claim is judged on the basis of only his presumptive ownership and not on the basis of his deed, i.e., is his deed of purchase ignored? Clearly, there is no reason to ignore the deed of purchase. Rather, say that Rabban Shimon ben Gamliel means that the defendant’s claim is judged not only on the basis of the deed of purchase, but even on the basis of his presumptive ownership. In other words, either claim suffices.

And we maintain that they disagree with regard to whether or not a litigant who claims to have more than one type of evidence is required to substantiate the existence of all his types of evidence. Rabbi Yehuda HaNasi holds that one who claims to have a deed of purchase is required to bring it to court and cannot rely on his presumptive ownership, whereas according to Rabban Shimon ben Gamliel he can rely on his presumptive ownership. Apparently, this dispute is parallel to the dispute between Rabbi Meir and the Rabbis in the mishna.

The Gemara rejects this: No. According to the opinion of Rabban Shimon ben Gamliel, everyone agrees that there is no need to substantiate the existence of all the types of evidence. When Rabbi Meir and the Rabbis disagree in the mishna it is according to the opinion of Rabbi Yehuda HaNasi, as Rabbi Meir holds that one is required to substantiate the existence of all of his types of evidence, in accordance with the opinion of Rabbi Yehuda HaNasi.

And the Rabbis could have said to you that Rabbi Yehuda HaNasi says there that one is required to substantiate the existence of his types of evidence only vis-à-vis a claim of presumptive ownership of the land. If one claims that he possesses the deed of sale for his land he cannot rely on his presumptive ownership, as the power of his presumptive ownership comes from the power of the deed; mere possession without an accompanying claim of how one became the owner is disregarded (see Bava Batra 41a). But here, in the case of two sets of witnesses, since the power of these witnesses does not come from the power of the other witnesses, even Rabbi Yehuda HaNasi concedes that one is not required to substantiate the existence of the other set of witnesses.

When Ravin came from Eretz Yisrael, he said that Rabbi Yoḥanan says a different interpretation of the dispute: The former clause, where Rabbi Meir rules that a litigant can disqualify a judge,