Other ways of authenticating the signatures on a document TB Ketubot 20

Up to now the Gemara has been focusing on one form of authenticating the witnesses’ signature. Sometimes the witnesses themselves will testify that this is their signature and sometimes other witnesses who recognize the first set of witnesses’ signature will testify to that fact. Today’s daf TB Ketubot 20 provides details about other means of validating a document.

“§ The Master said in the baraita cited previously: If there are other witnesses who testify that it is their handwriting, or if their handwriting emerges from another place, from a document that one challenged and that was deemed valid in court, these witnesses are not deemed credible. The Gemara infers: From a document that one challenged, yes, the signatures are authenticated and the testimony of the other witnesses is not accepted; however, if one did not challenge the document, no, the document cannot be used to authenticate their signatures. This supports the statement of Rabbi Asi, as Rabbi Asi said: One ratifies a document by authenticating the witnesses’ signatures only from a document that someone challenged and that was deemed valid in court.

“The Sages of Neharde’a say: One ratifies a document by authenticating the witnesses’ signatures only from two marriage contracts or from the bills of sale for two fields that those witnesses signed. And those bills of sale are effective only in a case where their owner ate their produce for three years, the requisite period to establish presumptive ownership of the field, and in peace, undisturbed by protest. In that case we can rely on the signatures, and the documents are considered valid.

“Rav Shimi bar Ashi said: Authentication of signatures by comparison to other documents can be accomplished specifically when the documents emerge from the possession of another. However, when the documents emerge from the possession of the litigant himself, no, they may not be used to authenticate the signatures. The Gemara asks: What is different in a case where the documents emerge from the possession of the litigant himself that they may not be used to authenticate the signatures? It is that perhaps while the documents were in his possession he learned how to copy the signatures and forged them. If so, also in a case where the documents emerge from the possession of another, perhaps he went and saw the signatures, and came back and forged them. The Gemara answers: In that case, he would not be able to accurately reproduce the signatures to that extent based on memory alone.” (Sefaria.org translation)

When comparing the signatures of two documents these qualifications must be met. First of all, the second documents signatures had to be challenged in court and verified to be accepted as authentic. Secondly, the two documents being compared must be the same as before the custom in Neharde’a. For example, the two documents must be two different ketubot or two different bills of sale. Last of all, the two documents cannot emerge from the litigant for fear of forgery. (Rambam, Mishneh Torah, Sefer Shoftim (Judges), the Laws of Testimony, chapter 6, Halakha 3; Shulkhan Arukh, Hoshen Mishpat, 46:7)