rabbah says: the yetzer hara incites only about who he sees. however on top of nedarim 20b, (end of perek)it says about IMMA shalom's practices in order to aviod thinking about other women at night. however if rabbah is correct what is imma shalom's practices all about.
similairly a little further down on that same amud is rebbe's statemnt that one should drink form one cup and set his eye on another (based on lo taturu acharei aynachem). if rabbah is correct, how is rebbe/imma shlaom's concerns possible unless they are actaully seeing the other women. otherwise it's assumed, as artscroll translates, rebbe is refering to -thinking- and not seeing- another woman.
does rabbah disagree with rebbe?
ike sultan, west orange, NJ
This is a difficult question but I will try and answer it for the time being as far as I am able. I do not think there is a disagreement between Rabah and Rebbi. It seems to me that the Gemara Nedarim 20b is not referring to someone thinking about another woman whom he had seen naked. Imma Shalom was the wife of Rebbi Eliezer - see Mesores ha'Shas Nedarim 20a in the name of Bava Metzia 59b - and Rebbi Eliezer had certainly not seen naked women. However he had seen the faces of other women, and what he was worried about was that particularly at the time of Tashmish with his wife, he would think about another woman. (Possibly this does not even necessarily mean thinking about their looks, but even their voice or personality).
It may be that because someone is having Tashmish with his wife, he is therefore thinking about a woman and consequently there is more of a concern about his thinking of a different woman. The Rosh in Nedarim explains that since Rebbi Eliezer was not light-headed at all during Tashmish, this ensured that he did not think about anything else. There is a special reason not to think about another woman at this time - because otherwise the children are considered similar to Mamzerim, as if they had come from a different mother.
In contrast, Gemara Sotah 8a is discussing someone who saw a naked woman. Rabah says that this will not lead him to want to do an Aveirah with a different woman. So this is not similar to Nedarim 20b - the latter does not say he wants necessarily to do an Aveirah with the other woman, but rather that he thinks about her at the time of Tashmish.
In summary there are 2 differences between the 2 Gemaras: (1) Sotah 8a discusses a naked woman while Nedarim 20b refers to any woman (2) Nedarim 20b refers specifically to thinking of her during Tashmish with one's wife.
[See also Melo ha'Ro'im Sotah 8a and Teshuvos Chasam Sofer YD end #184.]
Chodesh Tov
Dovid Bloom