Wednesday, March 03, 2010

rov and the source for "kol kavua"

I like the way Rav Amiel sets up this question in his Midos l'Cheiker Halacha: The famous sugya of tukfo kohen (B"M 6) speaks about an animal counted for ma'aser beheima which then jumps back into the pen of uncounted animals. This ruins the entire rest of the count, because from that point onward every 10 animals counted might have in the mix the one animal which jumped back in.

Tosfos and other Rishonim ask why this should be -- why not say that the one animal already counted is bateil to the rest of the herd which still needs to be counted?

The Rishonim answer that this is a special din based on a gezeiras hakasuv of "asiri" - vaday v'lo safeik. The designation of the 10th animal as ma'aser must be done with certainty; since any 10 animals taken at random from the herd might contain the one animal that shouldn't be there, there is no longer any certainty to the count. This is one of the popular sources that indicate that rov does not resolve uncertainty / safeik -- it merely allows us (in usual circumstances) to act or draw conclusions despite the latent uncertainty which remains. IOW, in yeshiva jarogon, rov is just a hanhaga, but not a birur.

Now for the fun. The gemara (Kesubos 15) presents the din of kol kavu'a k'machtza al machtza using the following case: let's say you have nine frogs and one sheretz in a mix and you stick your hand in and grab one. Even though the odds are that you touched a frog, the Torah has a chiddush that where you jump into the ta'aroves mixture (as opposed to, for example, one of the creatures jumping out at you) we treat the safeik as a 50/50 chance. The special din of kol kavua essentially eliminates the din of rov and levels the playing field of probability.

Here's the catch: the laws of how to treat safeik tumah differ from other areas of halacha. So long as the safeik arises in a private domain, no matter how many sefeikos are involved, the halacha is that safeik tumah b'reshus hayachid is tamei. So why do we need this special din of kol kavua? Since rov does not eliminate doubt --the safeik still remains, just the odds are tilted to one side over the other -- every case of safeik tumah b'reshus hayachid should be de facto tamei even without the rule of kol kavua! The very case of the mixture of frogs with a sheretz which is the paradigm of kol kavua seems to be a case where the chiddush is unnecessary to arrive at the conclusion.

Rov, kol kavua, tukfo kohen -- it doesn't get better than this : ) I won't spoil it by posting an answer just yet.


  1. Anonymous12:27 PM

    i dont understand. whether rov is a hanhaga or birur doesn't make a difference. rov takes away safek. its "manhig" to one side of the safek, if you will. before the lumdus, i thought this point is clear in different sugyos, none of which i can name, that rov takes away the safek.

  2. All I can say is that you see (lichorah) from the sugya of tukfo kohen that rov does not take away the safeik.

  3. rabbi akiva eiger has a teshuva about this, i think it's tinnyana siman 108. he says that the dinim of safeik tumah b'reshus hayachid and safeik tumah b'reshus harabim weren't said in a case where there is a rov because then its not similar to sotah which is the source of these dinim. Also, he answers that a rov which is used to answer a different safeq can be used to be מכריע the safeq at hand completely. I said over an entire chaburah on this inyan... :)

  4. >>>I said over an entire chaburah on this inyan... :)

    So why not write it up and share so the rest of us can enjoy?

  5. I have it written on paper and its eight pages in loshon hakodesh, it would take too long for me to translate it into English and there isn't such an english-speaking crowd that would appreciate it. Also, I'm busy revising some of my older writings.

    ...but other mareh mekomos on this sugya include reb aharon in the first siman in gittin, ע"ש.

  6. Anonymous10:58 AM

    From Tosfos Nidah 18a as explained in Shev shmatsa 4:2 we see that all the cases listed are  cases of rov vs chazakah. This would include the case of sheretz. Therefore we could say that although with sota  when there is a safek tumah in reshus hayachid we treat it as tameah rather than following the  regular rules of rov (where it would  remain a safek  and only the hanhaga of rov dictates how we treat it) here since there was a  preexisting cahzakah against the rov and there are no raglayim l’davar it remains a  safek and the rules of rov as a hanhagah rather than the rules of safek tumah apply as in  the case of  bechor
    In other words, sheretz is the exception (to the  din of safek tumah) because  there is a chazakah in addition to the rov. Therefore sheretz is just like  bechor and rov is only a hanhagah. Still even though the safek remains and rov is just a hanhagah, there would be no question from the klall of safek tumah

  7. I'm waiting to hear what Rav Chaim B. has to say about Anonymous'es Shev Shmaitsa. Nu?

  8. The Gemara of Kesuvos, 15a, is looking to prove that KaVuAh works LeKula, and therefore finally describes a case of 9 Sheratzim and one frog. In a public place, we Pasken the Safek TumAh is Tahor, but to have a Safek you must argue KaVuAh, because if not for KaVuAh we would follow the Rov and we would Pasken he is Tamei. See Rashi who writes quite clearly that Tov makes a certainty of the TumAh. Note, Rashi does not say the touchy is certainly Tamei but that there is certain TumAh here due to the Rov, which sounds pretty like it is a Birrur and not aHanHaGa.