Study Sanhedrin folio 31B with parallel Hebrew-English text, traditional commentary, and modern study tools. Free access to Babylonian Talmud online.
she could have burned it. Why did you not accept her testimony?
Rav Naḥman answered him: Since the promissory note was ratified in court, we do not say that she is deemed credible to nullify its validity because if she had wanted to, she could have burned it. The validity of a ratified document is not nullified without evidence.
Rava raised an objection to the ruling of Rav Naḥman from a baraita: A receipt [simfon] of repayment of a debt upon which witnesses are signed is ratified by means of its signatories. The witnesses testify that these are their signatures, and it is thereby ratified. If there are no witnesses signed
The Talmud concludes: The refutation of the opinion of Rav Naḥman is indeed a conclusive refutation.
§ When Rav Dimi came from Eretz Yisrael to Babylonia, he said that R' Yoḥanan said: One can always bring a proof for his claim and overturn the previous verdict, until his claims are stopped up, i.e., until he has no more claims, and he says: Come, so-and-so and so-and-so, and testify on my behalf