Formal fallacies “Formal” fallacies are errors in the form of a logical inference. Other names Non sequitur (“it does not follow”) In this section: General fallacies Circular reasoning Existential fallacy 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)
