The logical fallacy of accident, also called destroying the exception or a dicto simpliciter ad dictum secundum quid, is a deductive fallacy occurring in statistical syllogisms (an argument based on a generalization) when an exception to the generalization is ignored.

For instance:

1. Cars should never exceed the speed limit
2. Police cars are cars
3. Therefore, police cars should never exceed the speed limit

As a matter of fact the rule, cars should never exceed the speed limit, is only a general rule and police cars may be a valid exception.

Additionally:

1. Cutting people with a knife is a crime.
2. Surgeons cut people with knives.
3. Surgeons are criminals.

It is easy to construct fallacious arguments by apply general statements to specific incidents that are obviously exceptions.

Generalizations that are weak generally have more exceptions (the number of exceptions to the generalization need not be a minority of cases) and vice versa.

This fallacy may occur when we confuse generalizations ("some") for categorical statements ("always and everywhere"). It may be encouraged when no qualifying words like "some", "many", "rarely" etc. are used to mark the generalization.

For example:

Jews killed Jesus

The premise above could be used in an argument concluding that all Jews or current Jews should be responsible for Jesus' death. Qualifying the first term:

Some Jews killed Jesus

This premise may make it more obvious it is making an (extremely weak) generalization and not a categorical rule. The term could be made even more specific, such as "50-60 Jews in Judea living around 30 AD" from which it might be more difficult to attempt to draw a more wide-ranging conclusion.

Related inductive fallacies include: overwhelming exception, hasty generalization. See faulty generalization.

The opposing kind of dicto simpliciter fallacy is the converse accident.

External links

• Bruce Thompon's fallacies: Accident
• Fallacy files: Accident
• Stephen's Guide: Accident