>>3. All who hold Isur Mosif hold of Isur Kolel.
a) True.
b) False.
(c) Safek.
d) Machlokes A&B.
e) Machlokes A&C.<<
I think answer is false and not Safek.
Yossi, at first I thought I found a Tosfos who is on your side. This is Tosfos to Kerisus 23a, DH u'Mi, who writes that we find that Rebbi Yosi (Kerisus 14b) does not hold of Isur Mosif but he does hold of Isur Kolel.
However, after looking into it more, I see that Tosfos there says it the opposite way around -- that Rebbi Yosi does does not hold of Isur Kolel but he does hold of Isur Mosif.
And I did not have to go as far as Tosfos in Kerisus for this, because it is stated by Rashi on our Daf, 24b, DH Midi, who cites Yevamos 32b that even though Rebbi Yosi holds that we do not say Isur Chal Al Isur for Isur Kolel he agrees that for Isur Mosif we do say Isur Chal Al Isur.
Tosfos (24b, DH u'Man) also writes that according to the other Tana'im apart from Rebbi Shimon, even though they do not hold of Isur Kolel, they do hold of Isur Mosif, such as Rebbi Yosi.
However, I am now going to try to defend what we wrote that there is a Safek and it may be that all who hold Isur Mosif hold of Isur Kolel.
This is based on the Gemara in Yevamos 32b, that Rashi cites here, "Rebbi Yosi agrees with Isur Mosif." Tosfos (DH Isur) cites the Gemara there about a Kohen with a blemish (which is one Lav) who did Avodah when he was Tamei (which is another Lav). Rebbi Chiya jumped up and swore that he had heard from Rebbi that he is liable twice. Tosfos writes that Rebbi Chiya held that according to Rebbi Yosi he is liable twice in Isur Kolel.
This means that there is an opinion that just as one is liable twice for Isur Mosif so one is liable twice for Isur Kolel. This justifies what we wrote that it may be that all who hold Isur Mosif hold of Isur Kolel.
Dovid Bloom
I'm not sure what you're saying. The statement was "All who hold Isur Mosif hold of Isur Kolel.".
Rav Shimon holds Isur Mosif but does not Isur Kolel which means that not everyone who holds Isur Mosif holds Isur Kolel so the statement is false.
1) Tosfos here (24b, DH u'Man) writes explicilty that Rebbi Shimon does not hold of Isur Mosif.
2) I did find that the Yefeh Einayim to Pesachim 36b (DH ha'Ochel) writes that Rebbi Shimon does not hold of Isur Kolel but he does hold of Isur Mosif, which is what you argue, Yossi, but I cannot understand this because it is against our Tosfos on 24b who proves from Yevamos 32a that Rebbi Shimon does not hold of Isur Mosif. Tosfos in Kidushin 77b (DH Prat) also proves from Yevamos 32a that Rebbi Shimon does not even hold of Isur Mosif (in the question of Tosfos, he asked that for Isur Mosif Rebbi Shimon would say Isur Chal Al Isur, which is your Sevara, Yossi, but in his answer he rejects that). Tosfos in Kerisus 23a (DH u'Mi) also asks why do we not say that Rebbi Shimon agrees that for an Isur Mosif we say Isur Chal Al Isur, but Tosfos answers that the Shas knew that Rebbi Shimon does not even hold this for Isur Mosif, and then Tosfos cites the same proof from Yevamos 32a.
So I do not understand the Yefeh Einayim.
However, I now noticed that the Yefeh Einayim is asking a question, "Why do we not say Isur Mosif according to Rebbi Shimon?" but at the very end he answers, "According to Tosfos Kerisus 23a, this question is answered." So according to the Yefeh Einayim, also the conclusion is that Rebbi Shimon does not hold of Isur Mosif.
Dovid Bloom
I'm still not convinced. Rav Shimon is not a counter-example because he holds of neither so he's "not in the Parsha" for this question. However...
In the Gemara on top of 24B, Rava asks "what is the reason of the Tana who holds Isur Mosif but doesn't hold Isur Kolel?" The Gemara responds that he holds Isur chal al Isur by one Chaticha - i.e. Isur Mosif - but not by 2 Chatichos - i.e. Isur Kolel. This implies that there is at least one shita that holds Isur Mosif but doesn't hold Isur Kolel so the statement in the question is false.
Yossi
Yossi, thanks for your great feedback!
I do agree that Rava says in Shevuos 24b that there is a Tana who holds of Isur Mosif but does not hold of Isur Kollel. So, if one only learns Shevuos 24 and answers a Quiz Question on Shevuos 24, I concede that one would rightly say that "All who hold Isur Mosif hold of Isur Kollel" is false.
However, what I am arguing is that if one learns other Sugyos in Shas one sees that the statement "All who hold Isur Mosif hold of Isur Kollel" might be true. We see this in Yevamos 33a where Rebbi Chiya says that Rebbi Yosi holds that one is Chayev twice for Isur Kollel. Rashi in Kerisus 14b (DH Modeh) writes that this means that Rebbi Yosi holds both of Isur Mosif and Isur Kollel. So we see that Rebbi Chiya disagrees with Rava who says that Rebbi Yosi does not hold of Isur Kollel.
Now, the main dispute about Isur Mosif and Isur Kollel is a dispute among the Tana'im -- Rebbi Yosi, Rebbi Shimon, Rebbi Meir (who, in Yevamos 34a, holds both of Isur Kollel and Isur Mosif), and others.
The opinion of Rava is not an independent opinion; he is merely explaining the opinion of one of the Tana'im, Rebbi Yosi, as Rashi in Shevuos 24b (DH Midi) writes.
So when one writes "All who hold Isur Mosif hold of Isur Kollel" one really means "all the Tana'im who hold of Isur Mosif hold of Isur Kollel."
Therefore, this is a Safek, because Rava disagrees with this statement, but Rebbi Chiya agrees.
I concede that the answer to the Quiz Question is surprising if you take into account that it is a Quiz only on Shevuos 24, not on all of Shas. But I do not think that I will suggest that the answer be changed on our site because, with your help Yossi, I have learned so much from this which I would not otherwise have learned!
Yeyasher Kochacha!
Dovid Bloom