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Questionable Cause

cum hoc ergo propter hoc

(also known as: butterfly logic, ignoring a common cause, neglecting a common cause, confusing correlation and causation, confusing cause and effect, false cause, third cause, third-cause fallacy, juxtaposition [form of], reversing causality/wrong direction [form of])

Description: Concluding that one thing caused another, simply because they are regularly associated.

Logical Form:

A is regularly associated with B; therefore, A causes B.

Example #1:

Every time I go to sleep, the sun goes down.  Therefore, my going to sleep causes the sun to set.

Explanation: I hope the fallacious reasoning here is very clear and needs no explanation. 

Example #2:

Many homosexuals have AIDS. Therefore, homosexuality causes AIDS.

Explanation: While AIDS is found in a much larger percentage of the homosexual population than in the heterosexual population, we cannot conclude that homosexuality is the cause of AIDS, any more than we can conclude that heterosexuality is the cause of pregnancy.

Exception: When strong evidence is provided for causation, it is not a fallacy.

Variation: The juxtaposition fallacy is putting two items/ideas together, implying a causal connection, but never actually stating that one exists.

It’s funny how whenever you are around, the room smells bad.

Reversing causality or wrong direction is just what is sounds like -- it is still a false cause, but the specific case where one claims something like the sun sets because night time is coming.


Johnson, R. H., & Blair, J. A. (2006). Logical Self-defense. IDEA.

Registered User Comments

Thursday, December 20, 2018 - 09:44:06 AM
Explanation:" I hope the fallacious reasoning here is very clear and needs no explanation."
Sir when I saw your explanation of the 1st example,I sensed a fallacy in it.
You claimed that the example is very clear simply because many people may see it as clear as it appeared forgetting the very few people that may not understand the logic.

Can one say that you committed Argumentum ad populum?
Enlighten me please, am just a learner and I want to be a logical fallacy master like you, thanks.

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Bo Bennett, PhD
Thursday, December 20, 2018 - 09:57:57 AM
One could say anyone committed a fallacy, but that doesn't make it so.

To assume that most people realize that their going to sleep does not cause the sun to set is a reasonable assumption rather than an error in reasoning (if it is not, perhaps I have way too much faith in humanity), it is not an argument, and it doesn't fool the average adult (three criteria).

The problem illustrated in that example is based on the form of the fallacy "A is regularly associated with B; therefore, A causes B." Sleep (A) is regularly associated with the sun going down (B), therefore, sleep (A) cases the sun to go down (B). Which is fallacious reasoning.

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