Kiddushin 7b: Chatzi Isha, Partial Betrothal, and the Concept of Reservation

The shiur opens by examining a difficult sugya in Kiddushin 7b concerning partial betrothal (chatzi isha). The Gemara (גמרא) asks whether a man who says "half of you is betrothed" on one day versus two days creates a difference in halachic status. The fundamental question is what the man is trying to accomplish with such strange language—what is going through his mind when he says he wants to betroth "half" a woman? Rabbi Zweig presents several major difficulties in the sugya. First, the Rambam (רמב"ם) switches the order of the cases from how they appear in the Gemara, bringing the case of chatzi pruta v'chatzi pruta (half a perutah now, half later) first, then the case of shnei chatzayim (two halves simultaneously). Second, the Raavad raises a kasha: if the first case (chatzi isha) doesn't work because of ein isha ruyah lishnayim (a woman cannot be married to two men), then shnei chatzayim b'vas achas (two halves given at once) should certainly work, since there's only one man involved. Third, the Beis Yosef asks: if the Rambam rules that shnei chatzayim is a safek mekudeshes (possibly betrothed), why doesn't it work automatically through hispashtus (extension)—since she agrees to the whole thing, and there's no daas acheres (competing intention) blocking it?