concerning a conspiring witness: Abaye says: He is disqualified retroactively, from when he provided his testimony. Any testimony he may have provided after that point in time is retroactively nullified. And Rava says: He is disqualified only from that point forward, i.e., from when he was established to be a conspiring witness, but not retroactively from when he provided his testimony.

The Gemara explains the reasons for the two opinions: Abaye says he is disqualified retroactively because it is from that time when he testified that he is considered a wicked man. And the Torah stated: ''Do not put your hand with the wicked to be an unrighteous witness'' (Exodus 23:1), which is interpreted to mean: Do not allow a wicked man to serve as a witness.

Rava says that he is disqualified only from that point forward because the disqualification of a conspiring witness is a novelty, i.e., it is not based on logic. The reason is that this is a case of two witnesses against two other witnesses, in which case the testimony of neither should be accepted. What did you see that causes you to rely on the second set of witnesses, who testify that the first set were not at the scene of the purported event? You could instead rely upon the first set of witnesses, who testify to the event, and consequently disbelieve the second set. Yet the Torah teaches that the second set of witnesses is always deemed credible and the first set is subjected to punishment as conspiring witnesses. Therefore, as the disqualification of a conspiring witness is an anomaly, you have the right to disqualify him only from the time of its novelty and onward; this counterintuitive disqualification is not applied retroactively.

There are those who say that Rava also holds like Abaye, who says that by rights a conspiring witness should be disqualified retroactively from when he provided his testimony. And what is the reason Rava says that the witness is disqualified only from that point forward? It is due to the potential monetary loss for purchasers, whose acquisitions had been validated by these witnesses between the time of the witnesses’ first testimony and when they were rendered conspiring witnesses. If the disqualification of the witnesses were applied retroactively, as by right it should, all these transactions would be nullified, which would cause a loss to these purchasers.

The Gemara asks: What is the practical difference between these two explanations of Rava’s opinion? After all, according to both explanations Rava did not apply the disqualification of conspiring witnesses retroactively. The Gemara explains that there is a difference between them in a case where two witnesses testify about one of the witnesses that he was not at the scene of the supposed event, and two other witnesses testify about the other witness in a similar manner. Alternatively, there is a practical difference between the two explanations in a case where two witnesses disqualified the first set of witnesses by testifying that the first set had once committed robbery and are therefore unfit to give testimony. If the reason Rava does not disqualify conspiring witnesses retroactively is that it is a novel ruling, it is limited to that case. But if it is to protect purchasers, that would apply to the disqualifications of all witnesses, not only conspiring witnesses.

And Rav Yirmeya of Difti related: Rav Pappi once performed an action, i.e., issued a practical ruling, in accordance with the opinion of Rava. Mar bar Rav Ashi says: The halakha is in accordance with the opinion of Abaye.

The Gemara comments: And in disputes between Abaye and Rava the halakha is in accordance with the opinion of Rava, except for six cases in which the halakha is in accordance with the opinion of Abaye. They are: In the cases represented by the mnemonic yod, ayin, lamed, kuf, gimmel, mem: Unknown despair [ye’ush]; conspiring witnesses [eidim] who are disqualified retroactively; a side post [leḥi] standing alone; betrothal [kiddushin] that is not given to consummation; revealing intent with a bill of divorce [get]; and an apostate [mumar] who sins rebelliously.

§ The Gemara cites another dispute between Abaye and Rava with regard to disqualification of a witness. Concerning a transgressor who eats carcasses, i.e., non-kosher meat, due to appetite, i.e., because he desires this type of meat, or because it is less expensive or otherwise more accessible, everyone agrees that he is disqualified from bearing witness; it is suspected that just as he transgresses the halakhot of the Torah to satisfy his appetite, so too, he is willing to testify falsely for personal benefit.

With regard to one who eats non-kosher meat to express insolence, Abaye says that he is disqualified from bearing witness and Rava says that he is fit.

Abaye says he is disqualified because he is wicked, and the Merciful One states: Do not put the wicked in a position to serve as a witness. And Rava says that he is fit because for one to be disqualified from bearing witness we require him to be a wicked person guilty of specifically a monetary transgression [deḥamas], e.g., robbery. This is because the verse: ''Do not put your hand with the wicked to be an unrighteous [ḥamas] witness'' (Exodus 23:1) alludes to such a transgression.

The Gemara raises an objection to Rava’s opinion from a baraita: The verse: ''Do not put your hand with the wicked to be an unrighteous [ḥamas] witness,'' is interpreted in the following manner: Do not put the wicked in a position to serve as a witness; do not put one who is guilty of a monetary transgression in a position to serve as a witness. These are robbers and those who betray oaths, who are disqualified from bearing witness. The Gemara explains the objection: What, doesn’t the category of those who betray oaths refer to both one who takes an oath in vain, without any monetary application, and one who falsely takes an oath concerning monetary matters? Apparently, any transgressor is disqualified, even if he did so to express insolence and not for monetary gain.

The Gemara answers: No, both this and that oath included in the phrase in the baraita: Those who betray oaths, are oaths concerning monetary matters. And accordingly, what is the reason the baraita uses the word oaths, in the plural? The baraita is referring to oaths in general, not to multiple categories of oaths.

The Gemara raises an objection to Abaye’s opinion from a baraita: Do not put the wicked in a position to serve as a witness; do not put one who is guilty of a monetary transgression in a position to serve as a witness. These are robbers and those who lend money with interest. The fact that only monetary transgressions are mentioned does not accord with the opinion of Abaye. The Gemara concludes: The refutation of the opinion of Abaye is indeed a conclusive refutation.

The Gemara suggests: Let us say that this dispute is parallel to a dispute between tanna’im: A conspiring witness is disqualified from bearing witness about any matter in the entire Torah. This is the statement of Rabbi Meir. Rabbi Yosei says: In what situation is this statement said? Where he was rendered a conspiring witness with regard to a case of capital law; since he is assumed to have testified falsely with regard to a matter of life and death, he would certainly treat less serious testimonies lightly. Therefore, he is disqualified from bearing witness about any matter. But if he was rendered a conspiring witness with regard to a case of monetary law, he is fit to testify about cases of capital law, as there is no indication that he treats this matter lightly.

The Gemara concludes its suggestion: Let us say that the opinion of Abaye is in accordance with the opinion of Rabbi Meir, and the opinion of Rava is in accordance with the opinion of Rabbi Yosei. The Gemara clarifies: The opinion of Abaye is in accordance with the opinion of Rabbi Meir, who says that we say that from being rendered a conspiring witness with regard to a minor issue one is disqualified from bearing witness even with regard to a major issue. And the opinion of Rava is in accordance with the opinion of Rabbi Yosei, who says that we say that from being rendered a conspiring witness with regard to a relatively major issue one is disqualified with regard to a relatively minor issue; but we do not say that from being rendered a conspiring witness with regard to a relatively minor issue one is disqualified even with regard to a relatively major issue.

The Gemara rejects this suggestion: No. Everyone agrees that according to the opinion of Rabbi Yosei one who is rendered a conspiring witness with regard to a minor issue is not suspected of lying about a major issue. When Abaye and Rava disagree, it is according to the opinion of Rabbi Meir, i.e., they disagree concerning what Rabbi Meir holds.

Abaye holds in accordance with the opinion of Rabbi Meir, and derives from his opinion that one who eats non-kosher meat to express insolence is disqualified from bearing witness. And Rava holds that only there, with regard to a conspiring witness in a monetary case, does Rabbi Meir state his ruling that one who is rendered a conspiring witness about a minor issue is suspected of lying with regard to major issues as well. Rabbi Meir is of the opinion that he is both bad toward Heaven, having transgressed the prohibition against bearing false witness, and bad toward people, having caused another to lose money unrightfully. He is therefore suspected of testifying falsely with regard to any matter. But here, with regard to one who eats non-kosher meat to express insolence, a person who is bad toward Heaven but is not proven to be bad toward people, he is not disqualified.

The Gemara concludes: And the halakha is in accordance with the opinion of Abaye. The Gemara asks: But wasn’t his opinion conclusively refuted? The Gemara answers: That baraita from which Abaye’s opinion was refuted is in accordance with the opinion of Rabbi Yosei, and Abaye does not accept his opinion.

The Gemara asks: And let it even be in accordance with the opinion of Rabbi Yosei. According to the principles of halakhic ruling, in a dispute between Rabbi Meir and Rabbi Yosei, the halakha is in accordance with the opinion of Rabbi Yosei. How can his opinion be rejected?

The Gemara answers: There it is different, as the tanna taught us an unattributed mishna in accordance with the opinion of Rabbi Meir, and it is a general principle that the halakha is in accordance with rulings found in unattributed mishnayot. The Gemara asks: And where did the tanna teach us such an unattributed mishna?

The Gemara answers that this was established through a certain incident, as that incident occurred in which a man named bar Ḥama killed a person. The Exilarch said to Rav Abba bar Ya’akov: Go investigate this case, and if he certainly killed him, let them put his eyes out. Subsequently two witnesses came and testified that he certainly killed him. Bar Ḥama then went and brought two other witnesses, who testified about one of those first witnesses. One said: He stole, in my presence, a kav of barley; and one said: He stole, in my presence,