Affirming the consequent, sometimes called converse error, is a formal fallacy, committed by reasoning in the form:
An argument of this form is invalid, i.e., the conclusion can be false even when statements 1 and 2 are true. Since P was never asserted as the only sufficient condition for Q, other factors could account for Q (while P was false).
The name affirming the consequent derives from the premise Q, which affirms the "then" clause of the c...
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Affirming the consequent, sometimes called converse error, is a formal fallacy, committed by reasoning in the form:
An argument of this form is invalid, i.e., the conclusion can be false even when statements 1 and 2 are true. Since P was never asserted as the only sufficient condition for Q, other factors could account for Q (while P was false).
The name affirming the consequent derives from the premise Q, which affirms the "then" clause of the conditional premise.
One way to demonstrate the invalidity of this argument form is with a counterexample with true premises but an obviously false conclusion. For example:
Owning Fort Knox is not the only way to be rich. There are any number of other ways to be rich.
Arguments of the same form can sometimes seem superficially convincing, as in the following example:
But having the flu is not the only cause of a sore throat since many illnesses cause sore throat, such as the common cold or strep throat.
The following is a more subtle version of...
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