The false dichotomy plagues conversations in every sphere, not least in scholarship, theology, and politics! Not a day goes by where I do not encounter it even in prominent peer-reviewed publications. I suspect I am guilty of it more often than I realize, but I am watching out for it as much as possible in my own work and thinking.
A false dichotomy is the presentation (or implication) of two options or conclusions, either this or that, when in reality many other conclusions may be reached based on available evidence. A few examples from politics and biblical studies:
EITHER you enable laziness and remove incentives for work OR you stop food stamp programs for low-income families.
EITHER you support the Affordable Care Act OR you want to deny millions affordable health care.
EITHER “Christ” in Pauline lit. is a title OR “Christ” is a proper name. (Cf. Novenson, Christ among the Messiahs, who argues it is rather an honorific).
EITHER an NT book is pseudonymous OR it is penned by the putative author.
False dichotomies are often implicit in an argument and in our own thinking and difficult to detect. What is worse, sometimes the rejected option itself is a kind of straw-man and does not truly represent any person or argument.
Related to this error, we sometimes limit options to only a few (though more than two). For example, most discussions of the synoptic problem do not consider Matthean Posteriority but only Farrer, Farmer, and Two-Source. This, like other issues, is partly due to scholarly consensus(es) that can have a blinding effect.