Correction: I would like to change the term from "either-or thinking" to "false dilemma" which is more commonly used.

False Dilemma

Definition and Description


False dilemma (also called false dichotomy, bifurcation, black-and-white fallacy, either-or thinking) is a type of informal fallacy.

A dilemma is typically defined as a situation in which a choice has to be made between two equally undesirable alternatives. [1] The fallacy of the false dilemma is an attempt to convince you that such a situation exists by surreptitiously eliminating alternative outcomes.

While the name implies that only two options are available, this fallacy can be generalized to any situation where alternatives are illegitimately removed from the dialogue. Often, the false dilemma takes the extreme ends of a range of options and juxtaposes them in a single set of alternatives. [2]

The fallacy can arise either from careless omission of other alternatives or from intentionally persuasion of making a choice in someone’s favor.

Related Topic: Agumentation




  • Definition and Description

  • Examples

  • Analysis

  • Ways to Avoid False Dilemma In Your Reasoning

  • Other Logical Fallacies

  • References

  • External Links

  • Further Reading


  1. “Either you are with us, or you are with the terrorists.” [3]

The argument appeared in former US president George W. Bush’s address to a joint session of Congress on September 20, 2001. This implies that anyone who chooses not to stand by US and declare war against terrorists will regard as enemies just like those destructive terrorists, thus eliminate the middle ground for other countries.

Another similar example would be:

Eldridge Cleaver used such a quotation during his 1968 presidential campaign: “You're either part of the solution or part of the problem.” [4]

  1. False dilemma can also be commonly detected in advertisements and business proposals.

See the following example:

"Caldwell Hall is in bad shape. Either we tear it down and put up a new building, or we continue to risk students' safety. Obviously we shouldn't risk anyone's safety, so we must tear the building down." [5]

This argument neglects to mention the possibility that we might repair the building or find some way to protect students from the risks in question—for example, if only a few rooms are in bad shape, perhaps we shouldn't hold classes in those rooms.

The designers of these advertisements and proposals are deliberately committing the fallacy of false dilemma in an attempt to eliminate the possible options for their potential customers and clients and indirectly force them choose what the designers themselves prefer in the first place.


Though false dilemma is somewhat omniscient, it is sometimes difficult to detect the exact error in its reasoning because of the carefully and deliberately eliminated other possibilities.

So let’s take a look at a simple argument and analyses the underlying pattern of "reasoning" :

“It is hot today or it is cold.

Today is not hot.

Therefore it is cold today.”

And its underlying reasoning pattern is as follows:

Either claim P is true or claim Q is true (when Pand Q could both be false).

Claim Q is false.

Therefore claim P is true.

[just as indicated by the picture below]


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.[6]

Moreover, if another claim Q is also true and no substantial support has been provided to eliminate the claim, we cannot draw the above conclusion as well.

A more complicated example:

Gerda Reith is convinced that superstition can be a positive force. "It gives you a sense of control by making you think you can work out what's going to happen next," she says. "And it also makes you feel lucky. And to take a risk or to enter into a chancy situation, you really have to believe in your own luck. In that sense, it's a very useful way of thinking, because the alternative is fatalism, which is to say, 'Oh, there's nothing I can do.' At least superstition makes people do things."[7]

Analysis of this example:

Fatalism is not the alternative to superstition; it is an alternative. Superstition involves acting in ways that are ineffective, whereas fatalism involves failing to act even in situations in which our efforts can be effective. Fortunately, there are other alternatives, such as recognizing that there are some things we can control and other things we cannot, and only acting in the first case. [8]

Ways to Avoid a False Dilemma in Your Reasoning

When you draft an argumentative essay and would like to offer some advice, bear in mind that that often there are many different possible ways to resolve a problem in regard to the different causes to a result.

If you want to narrow down the options to the ones that you intend to underscore, do name other possible alternatives and rule them out reasonably one by one.

Therefore, examine your own arguments through the following questions:

  1. If you're saying that we have to choose between just two options, is that really so?

  2. Or are there other alternatives you haven't mentioned?

  3. If there are other alternatives, don't just ignore them—explain why they, too, should be ruled out.

*Although there's no formal name for it, assuming that there are only three options, four options, etc. when really there are more is similar to false dichotomy and should also be avoided.[9]

Other Logical Fallacies

There are of course a myriad of other logical fallacies in writing and speaking. Notice that they can be generally categorized as formal fallacy and informal fallacy.

An informal fallacy is one that is not formal, that is, it is a type of fallacy in which the content of the argument is relevant to its fallaciousness, or which is fallacious for epistemological, dialectical, or pragmatic reasons. [10]

Common informal fallacies (besides false dilemma) are listed as follows:



Appeal to Ignorance

Begging the Question


Division •Gambler's Fallacy

Non Causa Pro Causa


Red Herring Fallacy

Special Pleading


Weak Analogy

This site will give you a comprehensive and detailed explanation of the informal fallacies above.


  1. Della Thompson, ed. (1996) The Oxford Modern English Dictionary, Second Edition.Oxford University Press, New York, New York, United States.

  2. Informal Fallacy Primer

  3. Address to a Joint Session of Congress and the American People

  4. Yale Book of Quotations p158Speech to San Francisco Barristers Club, Sept. 1968



  7. David Newnham, //"Hostages to Fortune"//




External Links

This site is specially designed to collect any information relevant to logical fallacies and is well organized. It offers you an alphabetical list of fallacies and elaborates on examples, analysis, exposition, exposure of any one type of fallacy in question.

This PDF is a brief introduction to some common logical fallacies and ways to avoid them in your argument.

Further Reading

S. Morris Engel, With Good Reason: An Introduction to Informal Fallacies (Fifth Edition) (St. Martin's, 1994).

This entry was first drafted on May 27 and several adjustments and sctions were made or added in the days after. Then it was posted on June 5 when I see it as somewhat organized.