Dear Rabbi Kornfeld,
The Gemara on daf 15a near the bottom, "0mar Rav Huna", uses three different expressions for what seems to be the same thought: 1. Klapei Laia 2. Adraba and 3. Ipcha mistavra. Is there a reason for this?
Gershon
That's a very interesting observation you've made. After a quick look around the Shas with MTR (a free database program), I found the following:
(1) Klapei Laya: There are two ways the Gemara asks Klapei Laya - in the former, the Gemara is simply pointing out that there's an obvious mistake in the quote. No logical proofs are needed since the quote clearly ought to be the opposite of what it actually was. In such cases, the Gemara simply reverses the quote without further ado.
The other type of Klapei Laya is when the Gemara asks that if anything, the opposite should be true, and it backs itself up by suggesting a logical reason to reverse the quote. In such cases, the Gemara does not actually conclude that the quote must be reversed, but rather suggests another reading of the quote -- such as in our Sugya. Apparently the Gemara does not really mean that the quote must be reversed, but that its logical basis is weak. Therefore, the Gemara does not actually reverse the quote, since we cannot be certain that it ought to be reversed.
My quick review showed that the former type of Klapei Laya is unaccompanied by other terms of reversal, while the latter form, such as appears in our Sugya, is always accompanied by an "Ipcha Mistabra" (i.e., Klapei Laya just means, "it should be the opposite," while Ipcha Miztabra suggests why it should be reversed). As for "Aderaba":
(2) There are two types of Ipcha Mistabra. When the Gemara is simply explaining an opinion of an Amora etc., it simply says an unaccompanied "Ipcha Mistabra." However, when the Gemara says "Aderaba, Ipcha Mistabra" it means to state a Halachah . That is, we are not just asking a question, but we are stating that the opinion expressed earlier is wrong and the opposite is true.
If this is applied to our Sugya, it may suggest that although the Gemara does not actually reverse Rav Huna's statement due to the question of Klapei Laya, nevertheless, the reverse of Rav Huna's statement is indeed correct. This would be an interesting basis for the Rambam who quotes the Klapei Laya as Halachah (see Insights to Nidah 15).
Thanks!
-Mordecai
(P.S. - I later noticed that the Rishonim did not seem to have the word "Aderaba" in their texts, see Ritva.)