Rashi explains on the first mishna's second case that half of the tallis is not in dispute and needs no judgement.
Yet the oath given to the person on three fourths of the tallis includes his taking an oath upon the part of the tallis which was not in dispute.
This oath seems to share some aspects of a devolved oath, but it is not known to be a devolved oath.
Tosfos Yomtif apparently asks why the half not in dispute is included in the oath but from a different perspective.
And it is not clear from the description of the devolved oath in Kiddushin, (regarding a time before she was married) as referenced by the Artscroll comments in Bava Metzia whether a devolved oath can be either or both adding terms to a single oath or requiring multiple oaths, but also there it is applying the oath to something upon which she would not have otherwise had to take an oath, such as here on something not in dispute, not needing judgement.
If this were a devolved oath here in Bava Metzia would have to be first an oath upon the half that is not in dispute and then a second oath on the 3rd quarter?
Is there any way to re-vowelize "shaloshah" in the mishna to mean "third" rather than "three" so that specifically excludes the two not in dispute?
Is there any way to rephrase the whole oath so that there is still no room for trickery by establishing the context of the oath as a 3rd quarter beyond the two quarters not in dispute such that he is surely not being asked to take an oath on the first two quarters?
For example: In addition to the half of the tallis being awarded to me by Beis Din as not in dispute, there is in it not less than a 3rd quarter which is mine?
Chaim Chesler
Dear Chaim,
This is definitely not Gilgul Shevu'ah. Gilgul adds to an oath other points which even though they are not themselves deserving of any oath - because of a Halachic technicality or are not actively being claimed now against him/her, but if true will incriminate him. Here though even the other side agrees to him. There is no point to determine further.
The Nimukei Yosef (brought by the Tosfos Yom Tov) and also the Rosh (in the last lines of the Mishnah) explain that we are interested in making the clearest, simplest oath that will leave no doubt to it's meaning. Using complex phrases can cause a feeling to the oath-taker that he can manipulate (illegally) a foreign intention into the oath. But in this manner the black and white oath acts to stop him from lying.
There is no problem here of extra swearing. He is required to make one oath which will hopefully stop all bad intentions.
All the best,
Reuven Weiner