QUESTION: The Gemara cites a dispute among Amora'im about the nature of the allowance for a married woman, an "Eshes Ish," to marry another man based on the testimony of a single witness that her first husband is dead. Ze'iri maintains that the Heter is not a Heter instituted by Beis Din on her behalf. Rather, it is the Torah's Heter which Beis Din merely applies when it believes that the husband indeed is dead. The husband's unforeseen return shows that Beis Din was mistaken.

Rav Nachman disagrees and says that Beis Din does institute its own Heter on behalf of the woman. It is the Rabanan (and not the Torah) who grant permission to the woman to remarry, and the husband's unforeseen return does not render their ruling an error. Rather, if the husband returns, the permission they granted to her to remarry is revoked.

Rava attempts to prove that Ze'iri's opinion -- that when the husband returns alive Beis Din is considered to have erred -- is correct. Rava asserts that if Beis Din would issue a ruling to permit a certain questionable food item, and then readdress the question and prohibit the food, and then permit it again, no one would rely on that Beis Din's ruling to eat the questionable item. The case of the Gemara here is the same type of case, and yet Beis Din's words are accepted: Beis Din permits the woman to remarry based on the testimony of a single witness, and when two witnesses come and testify that the husband is alive Beis Din prohibits her from remarrying, and when another single witness comes and says that her husband is dead Beis Din again permits her to remarry. Why does Beis Din revert to its initial ruling? If the Heter (to remarry based on the testimony of a single witness) originates not from the Torah but from the Rabanan, they would not retract their second ruling and permit her to remarry, lest people not take them seriously. It must be that the Heter is not an enactment of Beis Din, but rather a Torah law which Beis Din merely erred in applying.

Rava's proof for Ze'iri's opinion is unclear. When a second single witness testifies after the testimony of a pair of witnesses, the case should become one of "Trei u'Trei" -- two against two, in which case the woman is not permitted to marry anyone other than one of the two witnesses who testify that her husband is dead (88b). This, however, is unrelated to whether the Heter is a specific enactment of the Rabanan or whether the Rabanan permitted her to remarry based on a mistake. In either case, the laws of "Trei u'Trei" should apply here. What is Rava's proof for Ze'iri's opinion?

(a) RASHI (DH Ki Hadar, as explained at length by the Rishonim) writes that the second single witness did not corroborate and uphold the testimony of the first single witness, and thus it is not a case of "Trei u'Trei." Rather, the second single witness said an entirely different testimony. He said that now the husband is dead, and that he was not dead at the time the first witness testified that he was dead. The testimony of the second witness provides new grounds on which to permit the woman to remarry.

Accordingly, Rava's intention is as follows: If the woman's allowance to remarry is a specific Heter instituted by the Rabanan, this means that although there is no compelling evidence that her husband is dead the Rabanan nevertheless permit her to remarry (Mishum Iguna). The Rabanan permit her based on the fact that the husband's whereabouts are unknown combined with the fact that a single witness says that he is dead. If the Heter is a specific enactment of the Rabanan, when two witnesses testify that the husband is still alive (and thereby require the woman to leave her second husband and to suffer all of the penalties of the Mishnah (87b)), she certainly will not want to get married again based on the testimony of another single witness with the same weak Heter of the Rabanan. Consequently, there is no point in issuing a Heter for her a second time. (This is the meaning of "Lo Mashgechinan Lehu" -- the woman will not listen to the Heter of Beis Din since she has suffered from the Heter once before.)

In contrast, if the basis for her allowance to remarry is not a provision of Beis Din but because Beis Din feels that there is sufficient proof that her husband died, then even though Beis Din is found to be mistaken the first time (the single witness was lying and the woman did not investigate the matter before she remarried), nevertheless when another single witness comes to testify Beis Din has no reason to assume that he is a liar or that the woman did not investigate the matter this time. (The fact that Beis Din made a mistake once does not forfeit Beis Din's credence for all future rulings.) Therefore, Beis Din may permit her to remarry the second time a single witness testifies. (See Insights to Yevamos 88:1, where the reason why a single witness is trusted to permit a woman to remarry is discussed. Tosfos maintains that it is an enactment of the Rabanan and is not based on a law in the Torah. Other Rishonim maintain that the Torah permits the Rabanan to rely on circumstantial evidence in such a case. The Gemara here seems to discuss this very point. According to Ze'iri, it is not a Heter of the Rabanan, but rather the Rabanan's application of a Torah law. In contrast, Rav Nachman maintains that it is a Heter of the Rabanan -- even though mid'Oraisa there is not sufficient proof to permit her to remarry, the Rabanan nevertheless were lenient and allowed her to remarry.)

(b) The RASHBA cites RABEINU MOSHE BAR YOSEF who explains Rava's intention as follows. If the Rabanan's ruling to permit her to remarry is based on their own Heter, then in the event that they have contradictory evidence about her marital status they should rely on the Chazakah that the woman is an "Eshes Ish" and may not remarry. Since until now the woman was forbidden to remarry, she should remain forbidden. Nevertheless, when the second single witness comes and supports the testimony of the first single witness, they create a situation of "Trei u'Trei" and the Rabanan permit her to marry one of the witnesses.

Why, though, may she remarry if she has a Chezkas Isur? It must be that when the Rabanan permit her to remarry based on the testimony of one witness, they are not issuing a Heter, but rather the testimony of one witness is valid proof that the husband is dead. If two witnesses come and testify to the contrary, the Rabanan declare the testimony of the first witness -- and the ruling based on that testimony -- to have been a mistake.

The logic of Rabeinu Moshe bar Yosef may be understood as follows. If the allowance for the woman to remarry is a Heter of the Rabanan, this means that the Rabanan enacted that the first witness who comes is granted the trustworthiness of two witnesses to permit the woman to remarry. If, however, the single witness has the status of two witnesses, why does Beis Din not accept that witness' testimony when two other witnesses come and contradict him? If the case becomes one of "Trei u'Trei," Beis Din should at least permit the woman to marry the single witness, as Beis Din permits her to marry one of the witnesses when a second single witness later testifies that her husband died. (This may be the Gemara's intention when it cites an example from the case of a forbidden food. If the Rabanan prohibit a certain food which they once permitted, they cannot suddenly decide to embrace their original ruling and permit the food when no further proof has come to that effect.)

It must be that the first witness was not granted the trustworthiness of two witnesses. Rather, the Rabanan permitted her to remarry based on the testimony and trustworthiness of a single witness. That is, they did not raise the level of validity of a single witness' testimony (to consider it like the testimony of two witnesses); rather, they lowered the requirements for permitting a woman to remarry and accepted a single witness' testimony as sufficient proof. Consequently, when two witnesses testify, they override the testimony of the single witness. When another single witness then comes and corroborates the testimony of the first, he joins with the first to increase his degree of trustworthiness; their testimony together now counters the other set of two witnesses.

In summary, if the allowance for the woman to remarry is a Heter enacted by the Rabanan, this means that the Rabanan enacted that the testimony of a single witness is to be treated like that of two witnesses. If the allowance for the woman to remarry is not due to an enactment of the Rabanan but rather it is the Torah's Heter which the Rabanan merely decide where (and where not) to apply, then the Torah permits the Rabanan to accept the testimony of a single witness even though they might be mistaken. (M. Kornfeld)