False Dilemma

Also Known as: Black & White Thinking.

A False Dilemma is a fallacy in which a person uses the following pattern of "reasoning":

  1. Either claim X is true or claim Y is true (when X and Y could both be false).
  2. Claim Y is false.
  3. Therefore claim X is true.

This line of "reasoning" is fallacious because if both claims could be false, then it cannot be inferred that one is true because the other is false. That this is the case is made clear by the following example:

  1. Either 1+1=4 or 1+1=12.
  2. It is not the case that 1+1=4.
  3. Therefore 1+1=12.

In cases in which the two options are, in fact, the only two options, this line of reasoning is not fallacious. For example:

  1. Bill is dead or he is alive.
  2. Bill is not dead.
  3. Therefore Bill is alive.


Examples of False Dilemma

  1. Senator Jill: "We'll have to cut education funding this year."
    Senator Bill: "Why?"
    Senator Jill: "Well, either we cut the social programs or we live with a huge deficit and we can't live with the deficit."
  2. Bill: "Jill and I both support having prayer in public schools."
    Jill: "Hey, I never said that!"
    Bill: "You're not an atheist are you Jill?"
  3. "Look, you are going to have to make up your mind. Either you decide that you can afford this stereo, or you decide you are going to do without music for a while."