Many of the early sugyot in Ketubot ask how we can trust a person’s word. In these cases, as we will soon see, the presence of corroborating witnesses can either help or, counter intuitively, complicate the matter. For example, consider this mishnah:
A woman who was widowed or divorced says: You married me as a virgin.
He says: No, I married you as a widow.
If there are witnesses that she went out on a hinuma (a couch on which virgin brides were carried out of their fathers’ houses) or her hair uncovered, her marriage contract is 200 dinars. Rabbi Yochanan ben Beroka says: Even the distribution of roasted grain is proof.
Rabbi Yehoshua concedes that a person is believed in a case where one says to one’s friend, “This field was your father’s, and I purchased it from him,” for the mouth that prohibits is the mouth that permits. However, if there were witnesses that it was his father’s and he says, “I purchased it from him,” he is not believed.
There are two scenarios here. In the first, a woman’s marriage ends and she claims the payment of a virgin (200 dinars), though her husband contests she was a widow when they married (so he owes her only 100). In this case, the sages look for witnesses to their wedding who can attest that she was celebrated as a virgin bride and thereby corroborate the woman’s claim.
Incorporating the evidence of witnesses is much trickier in the second scenario, in which Reuven disputes Shimon’s ownership of a field that once belonged to Reuven’s father (and, according to Reuven, still does). Shimon concedes that the field was once in the possession of Reuven’s father, but claims he subsequently purchased it from him.
Rabbi Yehoshua agrees with Rabban Gamliel (with whom he had several disputes in the previous chapter about who is to be believed) that Shimon is believed when he says he purchased the field. He is believed because of a concept the Gemara calls miggo. If he wanted an airtight claim without dispute, the rabbis reason, it would have been much simpler for him to claim that he owned the field all along.
Because, however, he admits that Reuven’s father did at one time own the field, an admission that could make his claim to now own the field less believable, we trust that he is telling the truth about everything — including his purchase of the field. In other words, if he were lying, he would likely have come up with a better lie so, the argument goes, we should believe him.
The catch is that this reasoning only works if there are no witnesses. If there are witnesses that Reuven’s father once owned the field, then Shimon would be foolish to lie about that fact. So we might suppose in that case that his claim to have purchased the field is untrue. In this case, witnesses that corroborate his story actually weaken our trust in him.
This concept is teased out in the sugya that follows the mishnah, where the Gemara examines the difference between this case and those where Rabbi Yehoshua disagrees. For example, an earlier mishnah states:
A man who marries a woman and finds that her hymen was ripped:
She says: I was raped after we were engaged, and your field was flooded.
He says: No, it was before we were engaged.
Rabban Gamliel and Rabbi Eliezer say she is believed, while Rabbi Yehoshua says: We don’t live by what comes from her mouth.
The question in this case is whether the woman had intercourse and then got engaged under a false pretense of virginity, or if the intercourse happened forcibly after the engagement, in which case the loss in her value is something that the groom, and not she, should absorb (hence the metaphor about his field being flooded).
In this case, we also have a miggo: She could have argued that her hymen was damaged for some other reason, such as an injury. This admission would have been far less uncomfortable to make. But she admits that she has in fact been forced and therefore she can be believed, according to Rabban Gamliel and Rabbi Eliezer.
So why does Rabbi Eliezer seem to accept the concept of miggo in some cases but not in others? The Gemara explains that in the second case she only offers her excuse once there is an indisputable fact that must be explained (her loss of the signs of virginity). In the first case, the actual field, there is no indisputable fact to be explained away, since the one admitting vulnerability is already in possession of the field. He wouldn’t have to admit this vulnerability to substantiate his claim, yet he did.
The Gemara gives us one strategy, miggo, for dealing with that uncertainty: We look to see if people’s claims do not serve them perfectly well, and view this as a sign of authenticity. But it’s only one of many strategies we will encounter in this tractate.
Read all of Ketubot 15 on Sefaria.