False Analogy (Fallacy)

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The fallacy of false analogy is an argument based on misleading, superficial, or implausible comparisons. Also known as faulty analogy, weak analogy, wrongful comparisonmetaphor as argument, and analogical fallacy.

"The analogical fallacy," says Madsen Pirie, "consists of supposing that things which are similar in one respect must be similar in others. It draws a comparison on the basis of what is known, and proceeds to assume that the unknown parts must also be similar" (How to Win Every Argument, 2015).


Analogies are commonly used for illustrative purposes to make a complex process or idea easier to understand. Analogies become false or faulty when they are overextended or presented as conclusive proof.

Etymology: From the Greek, "proportionate."


  • "There are seven windows given to animals in the domicile of the head: two nostrils, two eyes, two ears, and a mouth...From this and many other similarities in Nature, too tedious to enumerate, we gather that the number of planets must necessarily be seven." (Francesco Sizzi, 17th-century Italian astronomer)
  • "[F]alse analogy is central to jokes whose humour derives from ill-judged comparisons, as in the old joke where a mad scientist builds a rocket to the sun but plans to embark at night to avoid being cremated. Here a false analogy is created between the sun and a light bulb, suggesting that when the sun is not shining it is not 'turned on,' and hence, not hot." (Tony Veale, "Computability as a Test on Linguistic Theories." Cognitive Linguistics: Current Applications and Future Perspectives, ed. by Gitte Kristiansen et al. Mouton de Gruyter, 2006)
  • "When you find yourself reasoning by analogy, ask yourself two questions: (1) are the basic similarities greater and more significant than the obvious differences? and (2) am I over-relying on surface similarities and ignoring more essential differences?" (David Rosenwasser and Jill Stephen, Writing Analytically, 6th ed. Wadsworth, 2012)

    The Age of False Analogies

    "We are living in the age of the false, and often shameless, analogy. A slick advertising campaign compares the politicians working to dismantle Social Security to Franklin D. Roosevelt. In a new documentary, Enron: The Smartest Guys in the Room, Kenneth Lay compares attacks on his company to the terrorist attacks on the United States.

    "Intentionally misleading comparisons are becoming the dominant mode of public discourse...

    "The power of an analogy is that it can persuade people to transfer the feeling of certainty they have about one subject to another subject about which they may not have formed an opinion. But analogies are often undependable. Their weakness is that they rely on the dubious principle that, as one logic textbook puts it, 'because two things are similar in some respects they are similar in some other respects.' An error-producing 'fallacy of weak analogy' results when relevant differences outweigh relevant similarities."

    (Adam Cohen, "An SAT Without Analogies Is Like: (A) A Confused Citizenry..." The New York Times, March 13, 2005)

    The Mind-As-Computer Metaphor

    "The mind-as-computer metaphor helped [psychologists] to focus attention on questions of how the mind accomplishes various perceptual and cognitive tasks.

    The field of cognitive science grew up around such questions.

    "However, the mind-as-computer metaphor drew attention away from questions of evolution . . . creativity, social interaction, sexuality, family life, culture, status, money, power... As long as you ignore most of human life, the computer metaphor is terrific. Computers are human artifacts designed to fulfill human needs, such as increasing the value of Microsoft stock. They are not autonomous entities that evolved to survive and reproduce. This makes the computer metaphor very poor at helping psychologists to identify mental adaptations that evolved through natural and sexual selection."

    (Geoffrey Miller, 2000; quoted by Margaret Ann Boden in Mind as Machine: A History of Cognitive Science. Oxford University Press, 2006)

    The Darker Side of False Analogies

    "A false analogy occurs when the two things compared are not similar enough to warrant the comparison.

    Particularly common are inappropriate World War II analogies to Hitler's Nazi regime. For example, the Internet has more than 800,000 hits for the analogy 'animal Auschwitz,' which compares the treatment of animals to the treatment of Jews, gays and other groups during the Nazi era. Arguably, the treatment of animals is terrible in some cases, but it is arguably different in degree and kind from what happened in Nazi Germany."

    (Clella Jaffe, Public Speaking: Concepts and Skills for a Diverse Society, 6th ed. Wadsworth, 2010)

    The Lighter Side of False Analogies

    "'Next,' I said, in a carefully controlled tone, 'we will discuss False Analogy. Here is an example: Students should be allowed to look at their textbooks during examinations. After all, surgeons have X-rays to guide them during an operation, lawyers have briefs to guide them during a trial, carpenters have blueprints to guide them when they are building a house. Why, then, shouldn’t students be allowed to look at their textbooks during an examination?'

    "'There now,' [Polly] said enthusiastically, 'is the most marvy idea I’ve heard in years.'

    "'Polly,' I said testily, 'the argument is all wrong. Doctors, lawyers, and carpenters aren’t taking a test to see how much they have learned, but students are. The situations are altogether different, and you can’t make an analogy between them.'

    "'I still think it’s a good idea,' said Polly.

    "'Nuts,' I muttered."

    (Max Shulman, The Many Loves of Dobie Gillis. Doubleday, 1951)

    Further Reading