PHIL 210 Lecture Notes - Lecture 4: Modus Ponens, Persuasive Definition, Logical Form
23 May 2017
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Chapter 4 fallacies: when arguments turn bad. Three categories of fallacies: logical fallacies, evidential fallacies, procedural or pragmatic fallacies. Fallacy a way of arguing that is unreliable. Conditional fallacies two well known logical fallacies involving conditional arguments are: denying the antecedent. It is not the case that q: affirming the consequent. While denying the antecedent is easily confused with modus tollens. But that doesn"t mean the truth of the antecedent is necessary for the truth of the consequent. Scope fallacies quantifier scope fallacy this name for the fallacy indicates that it consists in a misordering of a universal quantifier (all, every, each) and an existential quantifier (some, a, the, one), resulting in an invalid inference. When an existential quantifier falls within the scope of a universal quantifier, we cannot validly rewrite this with the universal quantifier falling within the scope of the existential quantifier.
