A false dilemma (also called black-and/or-white thinking, bifurcation, denying a conjunct, the either-or fallacy, false
dichotomy, fallacy of exhaustive hypotheses, the fallacy of false choice, the fallacy of the false alternative, or the fallacy of the excluded middle) is a type of
informal fallacy that involves a situation in which limited alternatives are considered, when in fact there is at least one additional option. The opposite of this fallacy is
argument to moderation.
The options may be a position that is between two extremes (such as when there are shades of grey) or may be completely different alternatives. Phrasing that implies two options (dilemma, dichotomy,
black-and-white) may be replaced with other number-based nouns, such as a "false
trilemma" if something is reduced to only three options, instead of two.
False
dilemma can arise intentionally, when fallacy is used in an attempt to force a choice (such as, in some contexts, the assertion that "
if you are not with us, you are against us"). But the fallacy can also arise simply by accidental omission of additional options rather than by deliberate deception.