why does the gemra say our mishna is not a good proof for Rabbi Chia; If in our mishna where their are "witnesses" also for the 2nd side(i.e. loveh) and he still must swear of course then for rabbi Chai's din where only witnesses come for Malveh?
Question, USA
Since it is not logically consistent to assert that a Shavu'ah is taken where two witnesses support both half of the Malveh's claim and half of the Loveh's (since we do not doubt the words of witnesses), the Shevu'ah of our Mishnah cannot be attributed to Rebbi Chiya's Halachah. There must be another reason for the Shevu'ah of our Mishnah -- such as "Such that every person shall not go and grab his friend's Talis (3a, 5b). That reason would not apply in a normal case of Rebbi Chiya's (since a loan is involved, and not a quarrel over an object that both are holding), therefore we cannot deduce from this Mishnah that a Shevu'ah is taken in Rebbi Chiya's case. (See Rashi 4a DH Anan Sahadei)
Chanukah Same'ach,
Mordecai Kornfeld