[Avodah] nature of torah sheb`al peh

[Zev Sero via Avodah]

I just came across someone who has somehow gained the impression that 
mishnah is torah sheb`al peh, but gemara is not, and we may disagree 
with it.  "Mishnah is of course Torah sh'b'al peh; no one argues 
otherwise.  But while Gemara is encompassed within the rubric of the 
oral law, it is fundamentally different from Mishnah.  It is comprised 
of debate and dispute and assertions made without backup and incorrect 
statements and statements that seem problematic to our minds."

Any suggestions for how to counter this view most effectively, assuming 
he doesn't accept my mere assertion that this is not so?   Recommended 
reading?   I gather this person, who identifies as Orthodox, studies daf 
yomi in English but isn't very fluent in Hebrew.

-- 
Zev Sero                May 2017, with its *nine* days of Chanukah,
zev at sero.name           be a brilliant year for us all