False dilemma
|
|
The logical fallacy of false dilemma, also known as fallacy of the excluded middle, false dichotomy, either/or dilemma or bifurcation, is to set up two alternative points of view as if they were the only options, when they are not.
Examples:
- Either creationism must be true or Darwin's theory of evolution must be true. Therefore, if it is shown that Darwin's theory is false, then creationism must be true.
This argument is fallacious because its premise fails to recognize that there are many other possibilities than just Darwin's views and creationism. (If it were somehow proven that there were no other possibilities, then the logic would be sound. Until then, the argument is fallacious. In many cases, it can easily been shown that the assumed dilemma doesn't exist by coming up with a counter-example.)
False dilemmas are also common in politics. They are often hidden in (rhetorical) questions, and then become akin to the fallacy of many questions, as in:
- Will you re-elect Lyndon Johnson, or face nuclear holocaust?
- Are you with us, or with the terrorists?
A common use of the false dilemma is by parents trying to control the life-choices of teenagers:
- Either you go to college, or you will wind up flipping hamburgers for a living.
The false dilemma fallacy refers to misuse of the or operator. For another misuse of "or", see the false choice fallacy. For misuse of the and operator, see package deal fallacy.
A false dilemma may involve three possibilities (in which case it is known as a trifurcation) or more presented as if they are the only options.