Affirming The Consequent

Affirming the consequent, sometimes called converse error, is a formal fallacy, committed by reasoning in the form:

  1. If P, then Q.
  2. Q.
  3. Therefore, P.

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.

Read more about Affirming The Consequent:  Examples

Famous quotes containing the words affirming the, affirming and/or consequent:

    A large part of the popularity and persuasiveness of psychology comes from its being a sublimated spiritualism: a secular, ostensibly scientific way of affirming the primacy of “spirit” over matter.
    Susan Sontag (b. 1933)

    Most governments have been based, practically, on the denial of equal rights of men ... ours began, by affirming those rights. They said, some men are too ignorant, and vicious, to share in government. Possibly so, said we; and, by your system, you would always keep them ignorant, and vicious. We proposed to give all a chance; and we expected the weak to grow stronger, the ignorant wiser; and all better, and happier together.
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    Without this, as well as with it, we could have declared our independence of Great Britain; but without it, we could not, I think, have secured our free government, and consequent prosperity. No oppressed, people will fight, and endure, as our fathers did, without the promise of something better, than a mere change of masters.
    Abraham Lincoln (1809–1865)