Review of Monday - Tonight's shiur back on Webyeshiva site

Tonight, due to log in problems for some students, we will be back on Webex, ie Webyeshiva.org's website

On Monday night, we delved more into the mishna cited by Rava as the basis for the machloket between Rav and R. Chiya.

To review: 
In the case of 3 לוגין of water into which a קורטוב of wine dropped,
Rav Yehuda/Rav paskens that the mikvah is kosher - reasoning? It has a status of "diluted wine"
R. Chiya, however, cites a baraita that says - in the same fact situation -  הורידו את המקוה - which Rashi explains to mean: "Invalidate the mikva"

Rava explains that Rav is not contradicting R. Chiyah's baraita.  Rather, Rav has taken one side of a known Tannaitic debate, in a mishna in Masechet Mikva'aot.

The דתנן at the bottom of the page is the presentation of the issue as a machloket Tannaim.
The case - as we explained yesterday - is slightly different than ours - but we can infer from it halachic positions that match the views of Rav and the baraita of R. Chiya, respectively

The mishna deals with a case of 3 לוגין of drawn water MINUS a קורטוב, and the wine fills in the last קורטוב of the 3 לוגין - or a similar case in which milk dropped in.  In both cases, the mikva is kosher. 

Rashi helps us understand that the Tanna Kamma would invalidate the mikva were it to have had the full 3 לוגין of water before the wine dropped in.  Were it to have had the full amount, it would already have had the status of a "3 לוגין of מים שאובין" and could not have been transformed.  Tanna Kamma therefore lines up with R. Chiya's baraita.
However, R. Yochanan ben Nuri, who says הכל הולך אחר המראה - everything goes after the appearance, rules that even if 3 לוגין were present before the wine dropped in, such a mixture would not invalidate the mikvah.  This lines up with Rav!