False Dichotomy
From SkepticWiki
Contents |
[edit] Definition
The False Dichotomy fallacy, also called the Bifurcation or "black and white" fallacy, is an informal logical fallacy where an individual presents an argument having only few competing alternatives, but in reality there are many more. The fallacy in its general form looks like this:
- P or Q
- Not P
- Therefore Q
False dichotomy is not a valid form of induction.
[edit] Examples
The false dichotomy fallacy comes in several forms:
Example 1:
- Antagonist: "Either man was created just as the Bible tells us, or the man evolved from inanimate chemicals and random chance. The latter is so incredibly unlikely..."
Example 2:
- Antagonist: "You're either with us or against us."
In many cases, this fallacy will presented in a way where one horn of the dichotomy is clearly unacceptable, which forces an opponent to concede to the other "realistic" alternative:
- Antagonist: "Either the boy stabbed his father, or the knife just grew a pair of wings and began stabbing all by itself..."
- Antagonist: "If you don't support the PATRIOT Act, you support the terrorists."
In certain cases, an individual may present a false dichotomy, procede to weed out the unacceptable alternatives, leaving the alternative the individual prefers as the only "viable" alternative.
- Antagonist: "If the dog didn't steal my pizza, it must have been a ghost? Yeah right..."
- Antagonist: "Either Jesus Christ was a liar, a lunatic, or the Lord. No liar would want to die, and Jesus' profound moral conclusions certainly couldn't have come from a lunatic, therefore we conclude he was the Lord" - there are obviously more alternatives than just these three (for instance, we could question whether the Gospel's are historically accurate, whether the words attributed to Christ were really his own, whether Jesus Christ even existed at all).
[edit] Exceptions to the Rule
Not all examples of "either this alternative or that alternative" are constitutive of the false dichotomy fallacy. In some cases, there really are two alternatives, such as "either the man is guilty of the crime, or he is not guilty of the crime".
As another awkward exception, not all alternatives need to be considered, such as hypothesizing unfalsifiable claims (e.g. it would do no good to say to someone "you have not eliminated the possibility of creatures from a parallel dimension stealing your wallet"). Such multiplication of hypotheses is disallowed by use of Occam's Razor.
