formal fallacy
Quick Summary
A formal fallacy is a flaw in the structure or form of an argument, making it invalid. This means that even if the premises are true, the conclusion does not logically follow. Formal fallacies are distinct from material fallacies (errors in the content or facts) and verbal fallacies (errors due to ambiguous wording).1
Examples of formal fallacies include:
* Denial of the antecedent: Arguing that if P then Q, and not P, therefore not Q.
* Affirmation of the consequent: Arguing that if P then Q, and Q, therefore P.
* Illicit major/minor: Violations of the rules of distribution in syllogisms.1
Formal logic, the study of these structures, abstracts away from the specific content of arguments to focus on their underlying forms.2
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