Formal fallacies
“Formal” fallacies are errors in the
form
of a logical inference.
Other names
Non sequitur
(“it does not follow”)
In this section:
Propositional logic
Affirming a disjunct
Affirming the consequent
Denying a conjunct
Denying the antecedent
Syllogistic fallacies
Affirmative conclusion from a negative premise
Negative conclusion from affirmative premises
Fallacy of exclusive premises
Fallacies of distribution
Illicit process
(undistributed minor/major)
Undistributed middle
Four-term fallacy
Ambiguous middle (term)
Other formal fallacies
Circular reasoning
Existential fallacy