103b (Mishnah - R. Chanina Segan ha'Kohanim): I never saw a skin taken to Beis ha'Sereifah (to be burned due to a Pesul).

R. Akiva: From R. Chanina we learn that (even) if a Bechor was found to be Treifah after flaying, Kohanim receive the skin.

Chachamim: Not seeing is not a proof! The Halachah is, it goes to Beis ha'Sereifah.

104a: The Halachah follows Chachamim.

Kesuvos 22b (Beraisa): If two witnesses say that a woman became Mekudeshes and two say that she did not; she may not marry (someone else). If she married, she may remain married;

If two say that she was divorced and two say that she was not, she may not remarry. If she remarried, she must leave him.

Question: Why is the law different in the two cases?

Answer #1 (Abaye): Really, only one witness testified about the Kidushin or divorce, and one contradicts him. In the Reisha, both testify that she was single. Only one says that she became Mekudeshes. One is not believed against two. In the Seifa, both testify that she was married. Only one says that she was divorced. One is not believed against two.

Answer #2 (Rav Ashi): Really, there are two witnesses on each side, but we must switch the laws of the two cases. If two say that she accepted Kidushin and two say that they did not see it, she may not marry. If she married, she must leave;

Interjection: This is obvious. Not seeing is not a proof!

Answer: The case is, they live in the same courtyard. One might have thought that since Kidushin is publicized, they certainly would have known (and we consider the testimonies to be contradictory). The Beraisa teaches that this is not so. Some people are Mekadesh covertly.

The Seifa says that if two say that she was divorced and two say that they did not see her divorced, she may not remarry. If she remarried, she may remain married.

Question: The Reisha already teaches that even if they live in the same courtyard, (b'Di'eved if she remarried) we are not concerned for the witnesses who did not see!

Answer: One might have thought that people are Mekadesh covertly, but divorce is publicized, so certainly they would have known. The Seifa teaches that also divorce can be done covertly.

Sotah 47a (Mishnah): If a murdered corpse was found, and one witness says that he saw the murderer, and one witness says 'you did not see', we bring Eglah Arufah (behead a calf for atonement).

Mordechai (Sanhedrin 725): If witnesses say that they were there and being meticulous, and they did not see Kidushin or divorce, it is not clear whether we say that not seeing is not a proof. Presumably, it is not a proof only when we can say that one saw and another did not, e.g. they live in one Chatzer. This is not a contradiction. However, when they were together, and one says that he did not see, it is as if he says 'you did not see.' This is a contradiction. If one witness says that he saw the murderer, and one says 'I did not see' (our text in Sotah is 'you did not see), this is called contradiction.

Beis Yosef (CM 29 DH v'Chasav): I say that this is (contradiction) when the witnesses say 'we did not leave him (even for a moment - Yevamos 88a).

Rebuttal (Darchei Moshe CM 30:7): As long as they were in one gathering, not seeing is a proof, like we say in EH 47 (brought below).

Maharik (171): When do we say that not seeing is not a proof and not hearing is not a proof? If two pairs of witnesses contradict each other, i.e. one pair says that they saw Kidushin, and the other says that they did not see. However, when there is no contradiction, e.g. if no one testifies that the custom was to be stringent about Sivlonos (prenuptial gifts, to consider that she is Safek Mekudeshes), surely we rely on those who testify and say that they never saw or heard anyone (be stringent).

Shulchan Aruch (EH 47:1): If two witnesses saw Leah accept Kidushin, and two say that they did not see, she is Mekudeshes, even if all of them live in the Chatzer. Not seeing is not a proof, for perhaps she accepted Kidushin covertly.

Beis Yosef (DH Shenayim): R. Yerucham (23:3 195b) says that if they were in one gathering, we could say that people are not Mekadesh so covertly, and this is contradiction.

Beis Shmuel (1): However, if they all were together in one assembly, it is a Safek (Sa'if 2).

Shulchan Aruch (2): If two witnesses saw that she became Mekudeshes, and two say that she did not, whether Kidushin was thrown and they argue about whether it landed closer to her or to him, or whether the latter say that there was never Safek Kidushin, she may not remarry. If she remarried, she need not leave.

Shulchan Aruch (CM 29:3): Even though not seeing is not a proof, when they were together, and one says 'I did not see', it is as if he says to the other 'you did not see', and this is contradiction.

SMA (12): Here, the Mechaber himself rules Stam (without mentioning another opinion) like the Darchei Moshe (brought above).

Gra (17): We learn from Zevachim that not seeing is not a proof.

Gra (19): We learn from Sotah that when they were together, it is as if he says 'you did not see.'

Teshuvas R. Betzalel Ashkenazi (9): We did not hear or see anyone conduct like people of Galil (who say that orphans can force the widow to accept her Kesuvah to exempt themselves of the obligation to feed her). All Rabanan say that when there is a custom, we follow it. Maharik says that not seeing is not a proof only when two pairs of witnesses contradict each other; one saw Kidushin, and the other did not. When there is no contradiction, e.g. no one testified that people used to be stringent about Sivlonos, surely we rely on those who testify that they did not see or hear.

Maharashdam (EH 90): A case occurred in which a Shechiv Mera (a sick person who fears lest he die) authorized to write and give a Get on the day he died, and it was given shortly before death. Two witnesses say that he was Mevatel it before he died, and two witnesses said that they did not leave him the entire day, and they saw that he was not Mevatel it. This requires great investigation of an expert Beis Din. It is very easy to be Mevatel a Get. Perhaps they did not hear! It is farfetched to say that they guarded (to hear everything that came out of) his mouth the entire day. If so, the latter testimony is invalid. We find in Kesuvos that since people often are Mekadesh covertly, not seeing is not a proof. This is even for Kidushin, even though usually there is a Kol (publicity) to Kidushin! All the more so it applies here, for perhaps most people are Mevatel Gitin covertly, for they do not want to publicize this, especially a Shechiv Mera who is weak. He was Mevatel quietly in front of two, and the others did not hear.

Maharshach (1:28): A witness testified that he went to a certain city during Chanukah of a certain year, and Leah was still not born. This is not testimony, for not seeing is not a proof, unless the witnesses say 'we did not leave her (mother).' Surely they were not with her the entire time! In Kesuvos, we say that some people have Kidushin covertly. Likewise, some people gave birth covertly!

Sha'ar Efrayim (112): In a situation where saying 'I did not see' is like saying '(also) you did not see', this is a contradiction. People do not err about whether an act was done. However, if one says that he heard something, and another says that he did not hear like this, this is not a contradiction, for people often err about what they heard. It is unlike seeing. However, Maharashdam, Maharshach and R. Betzalel Ashkenazi (7) equate hearing to seeing. Heaven forbid to go against great Poskim based on our own reasoning, even if it seems like a good distinction. However, the Ran (Teshuvah 34) says that Beis Din must try to explain the words of the witnesses so that there will be no contradiction, lest one of them be a Rasha. We learn from witnesses who differ about the day of the month. We say that one of them knew which day was Rosh Chodesh, and one erred. Likewise, if some witnesses heard Leah say that she did Mi'un (annulled her marriage mid'Rabanan), and some heard this only from Leah's mother, this is no contradiction. Perhaps Leah herself said so only after some of the witnesses had left.