Bava Metzia

OR DURING THE HOUR FOR WHICH IT WAS BORROWED; AND THE OTHER REPLIES, 'I DO NOT KNOW', HE MUST PAY. IF THE HIRER ASSERTS: THE HIRED ONE DIED, [OR], IT DIED ON THE DAY WHEN IT WAS HIRED, OR IT DIED DURING THE HOUR FOR WHICH IT WAS HIRED, AND THE OTHER REPLIES, 'I DO NOT KNOW,' HE IS NOT LIABLE. BUT IF ONE ASSERTS THAT IT WAS THE BORROWED ONE AND THE OTHER THAT IT WAS THE HIRED ONE, THE HIRER MUST SWEAR THAT THE HIRED ONE DIED [WHICH FREES HIM FROM LIABILITY]. IF THE ONE SAYS, 'I DO NOT KNOW,' AND THE OTHER SAYS, 'I DO NOT KNOW,' THEY MUST DIVIDE. GEMARA. Hence it follows, [that if A says to B,] 'You owe me a maneh,' and B pleads, 'I do not know,' he is bound to pay. Shall we say that this refutes R. Nahman? For it has been taught: [If A says to B,] 'You owe me a maneh,' and B pleads, 'I do not know,' R. Huna and Rab Judah rule that he must pay; R. Nahman and R. Johanan say: He is not liable! — It is as R. Nahman answered [elsewhere], e.g., there is a dispute between them involving an oath; so here too, it means that there is a dispute between them involving an oath.  What is meant by a dispute involving an oath? — As Raba's [dictum].