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Fallacy of accident

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Part of the series on
Logic and rhetoric
Icon logic.svg
Key articles
General logic
Bad logic
Not to be confused with overgeneralization or fallacy of accent.
No rule is so general, which admits not some exception.
—Robert Burton, The Anatomy of Melancholy

Fallacy of accident is a logical fallacy that occurs when a general rule (a rule of thumb or a "soft" generalization) is taken to be universal (an unconditionally true statement).

The fallacy is an imprecision fallacy and an informal fallacy.

Alternate names[edit]

  • a dicto simpliciter ad dictum secundum quid
  • sweeping generalization
  • misuse of a principle
  • ignoring qualifications

Form[edit]

P1: Bs are normally Cs.
P2: A (an abnormal example) is a B.
C1: A is C.

Examples[edit]

Water boils at a temperature of 212° Fahrenheit; therefore boiling water will be hot enough to cook an egg hard in five minutes: but if we argue thus at an altitude of 5,000 feet, we shall be disappointed; for the height, through the difference in the pressure of the air, qualifies the truth of our general principle.
—H. W. B. Joseph
  • "Birds can [normally] fly" is a general rule, and doesn't imply that all birds (such as emus or penguins) can fly. To take this general rule and apply it to all birds would be committing a sweeping generalization.

Subfallacies[edit]

External links[edit]