Dear Rav Kornfeld,
In our shul's dafyomi shiur we covered the case of a betrothed woman, that the man to whom she is betrothed cannot be a witness for or against her even though they are not fully married.
I recall in Kidushin that a Yevamah, once she accepts the rabbinic enactment gift from one of the brothers, she is described as considered as if married to him from the perspective of all other brothers.
I am not sure if I am also remembering from there that her case is compared with the normal case of Kidushin, that from that point on she is not permitted to marry any other man, that it is as if they are married in that way - if so that is more directly on point with what I want to ask...
Why doesn't the Gemara say that he is considered too close to be a witness or a judge because she is as if she is married to him from the perspective of all other men?
Why does the Gemara only say that it is because they are close in their thoughts, or however it puts it, if it had this other analysis by which it could have said something?
You make a good point. I think the Gemara means as follows- Being a Karov makes you Pasul to be a witness. The Gemara says that maybe this is only after Nesu'in-like by mourning and inheritance. But then the Gemara explains that by these two we need She'er, which is Kiruv Basar -physical closeness (Baba Metzia 18a Rashi DH v'Hu Metamei). But here the Kiruv which effects testimony is Kiruv Da'as which exists even by Erusin. (It could be that her being forbidden to others contributes to this Kiruv Da'as- but to say that being forbidden to others makes her a Karov doesn't explain anything unless we define what Kiruv here is- Kiruv Da'as as opposed to She'er which is Kiruv Basar.
All the best,