29b
Rashi d'h Hashta arusa
Says that maamar is a derabonon according to beis shammai.
But how on earth can we say that maamar is derabono according to the masking of any of the explanations of beis shammai. Both the original exp. of reb eliezer and reb ashi both of them agree that maamar will patter the tzoro/sister from chalitza, so therefore maamar must have an effect midoirasa!
I was thinking perhaps you can say an enormous chiddush.
Maybe beis shammai truly hold that maamar is only derabonon, and the only reason that the tzoro does not need chalitza min hatorah, is because the chachomim, using their koach, can be oker the kiddushin of the 1st brother, so that his wife is mutar to the shuk without chalitza. And that is hiw maamar works. Cos the chachomim said, we consider maamar like a real kiddushin and we will be matttir the tzoro to the shuk, using our own methods. However the chachomim do not hqve a koach to make a kiddushin doiraisa, where a kiddushin does not exist. Therefore the gemoro rightfully asks, even if maamar is good it is certainly not like erusin.
Avrumi Hersh, London england
Avrumi, I think you may have been mekaven to Tosfos Rabeinu Peretz 29a DH B"SH, who defends the shittah of Rashi from the question of Tosfos 29a DH B"SH and writes that this works according to the principle (Yevamos 90b) "Man deMekadesh Ada'ata deRabonon Mekadesh veAfka'inhu Rabonon leKidushin Minay"; anyone who marries does so according to the rules of the Chazal so they can uproot his kidushin.
KOL TUV
Dovid Bloom
Follow-up reply:-
1) After looking more closely at Tosfos Rabeinu Peretz he does not say that Chazal are oker the kidushin of the first brother, but what he seems to say is that Chazal were oker the possibility that the single brother, who did Maaamar in Mishnah 29a with the widow of the deceased brother, could ever marry the second sister. Even if he would try to marry this second sister, Chazal would uproot this marriage. Since he could never marry the 2nd sister, it follows that she does not require chalitzah, since Chazal have uprooted any connection between the single brother and the second sister. This is a somewhat smaller chidush than saying that the 1st brother was never married to his wife.
2) I saw a nice idea in Sefer Menuchas Aharon on Yevamos 18a #45. He also wants to say that Rashi learns according to Beis Shamai that "Kol Hamekadesh Ada'ata deRabonon Mekadesh" but the uprooting that Chazal did is again slightly different. Chazal said that when someoene gets married, he does so on the understanding that if he should die childless and his brother should do Maamar with the widow, he should do so in such a way that the other sisters should be totally exempt from any connection to the brother-in-law. The reason he can do this is based on Rashi Kidushin end 4b DH She-Kein who writes that the widow is zekukah to the brother-in-law because of the kidushin with the first husband. Menuchas Aharon writes that the Zikah of Yibum is a remnant of the 1st marriage. This is why Chazal can determine what connection there is between the brother-in-law and the sisters.
3) As you write, Kol Hamekadesh Ada'ta deRabonon Mekadesh can only mean that somebody was not married even though he thought he was. It cannot mean that he is married even though he did nothing for this.
Yasher Koach
Dovid Bloom
Rav Ashi says that, according to Rav Elazar, chalitzah is still required after Maamar:-
I should just point out that Rav Ashi stated on 29b that Rav Elazar said that one should not say that according to Beis Shamai one does not need chalitzah after Maamar. Maamar does not patter the tzora from chalitzah.
Dovid Bloom