Bava Batra 35aChapter 3 Chezkat HaBattim

דְּרַב אָמַר: יַחְלוֹקוּ, וּשְׁמוּאֵל אָמַר: שׁוּדָא דְּדַיָּינֵי? הָתָם, לֵיכָּא לְמֵיקַם עֲלַהּ דְּמִילְּתָא; הָכָא, אִיכָּא לְמֵיקַם עֲלַהּ דְּמִילְּתָא.

as Rav said: In that case, they should divide the property between them, and Shmuel said: It is decided based on the discretion [ shudda ] of the judges. Why in the seemingly equivalent case of a dispute where there is no evidence for either litigant did Rav Naḥman rule that whoever is stronger prevails? The Gemara answers: There, in the case of the two deeds, it will not be possible for the court to clarify the matter in the future, and therefore, the court issues a ruling according to the information they currently have. Here, in the case of Rav Naḥman, it may be possible for the court to clarify the matter in the future, if one of the litigants was to bring witnesses supporting his claim.

וּמַאי שְׁנָא מֵהָא דִּתְנַן: הַמַּחֲלִיף פָּרָה בַּחֲמוֹר, וְיָלְדָה; וְכֵן הַמּוֹכֵר שִׁפְחָתוֹ, וְיָלְדָה – זֶה אוֹמֵר: ״עַד שֶׁלֹּא מָכַרְתִּי יָלְדָה״, וְזֶה אוֹמֵר: ״מִשֶּׁלָּקַחְתִּי יָלְדָה״ – יַחְלוֹקוּ?

The Gemara asks: And in what way is this case different from that which we learned in a mishna ( Bava Metzia 100a): With regard to one who exchanges a cow for a donkey and the cow calved, and similarly one who sells his Canaanite maidservant and she gave birth, and this one, i.e., the seller, says: She gave birth before I sold either the cow or maidservant, and the offspring belongs to me; and that one, i.e., the buyer, says: She gave birth after I purchased her and the offspring belongs to me, the ruling is that they should divide the value of the newborn. In that case, the court is not able to clarify the matter, so they should rule that whoever is stronger prevails.

הָתָם, לְהַאי

The Gemara answers: There, in the case of the exchange, for this one, i.e., the buyer,