A false dilemma (also called false dichotomy, black-and/or-white thinking, the either-or fallacy, the fallacy of false choice, the fallacy of exhaustive hypotheses, 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 2 options (dilemma, dichotomy, black-and-white) may be substituted with other number-based nouns, such as a “false trilemma” if something is reduced to only 3 options, instead of 2.
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.
In the community of philosophers and scholars, many believe that “unless a distinction can be made rigorous and precise it isn’t really a distinction.” An exception is analytic philosopher John Searle, who called it an incorrect assumption which produces false dichotomies. Searle insists that “it is a condition of the adequacy of a precise theory of an indeterminate phenomenon that it should precisely characterize that phenomenon as indeterminate; and a distinction is no less a distinction for allowing for a family of related, marginal, diverging cases.” Similarly, when two options are presented, they are often, though not always, two extreme points on some spectrum of possibilities; this can lend credence to the larger argument by giving the impression that the options are mutually exclusive, even though they need not be. Furthermore, the options in false dichotomies are typically presented as being collectively exhaustive, in which case the fallacy can be overcome, or at least weakened, by considering other possibilities, or perhaps by considering a whole spectrum of possibilities, as in fuzzy logic.