More Discussions for this daf
1. The Shevu'ah of Shenayim Ochzin 2. Picking up a Metzi'ah 3. Owning all of it
4. Sumchus or the Rabanan 5. Tosfos DH Yachloku 6. Questions in Rashi
7. Case of Mekach U'Memkar 8. Rashi According to Maskanas ha'Gemara 9. Shenayim Ochzin b'Talis
10. "It is all mine" 11. Arguing over a lost object that was found 12. Causing a Shevu'as Shav in our Mishnah
13. Teaching that Re'iyah is not Koneh 14. Two versions 15. Comparing 3/4 Talis oath with devolved oath
16. Acquiring through seeing 17. Terms of Chazakah and ownership 18. בבא מציעא ב. תד"ה בראיה - הבטה בהפקר
DAF DISCUSSIONS - BAVA METZIA 2

Yaakov Richter asked:

What is the hava amina of the gemarah that one can be koneh (or zocheh) an object through ri'iah?

Yaakov Richter, New York, United States

The Kollel replies:

Rav Pinchas Teitz zt'l once offered to me an explanation as follows (as I recall). A lost object with a Siman must be returned to its owner, as per the Mitzvah of Hashev Teshivem. A person becomes obligated in that Mitzvah the moment that he sees the object (Bava Metzia 26b). Perhaps, since a person becomes obligated in the Mitzvah by seeing, he can also acquire the object by seeing if it doesn't have a Siman.

(Otherwise, Tosfos references Bava Metzia 118a, where the Gemara discusses whether "Habatah" is Koneh. Rashi there does not seem to require building a fence etc. as Tosfos here mentions; just putting effort into watching the object.)

M. Kornfeld