PHIL 110: Argument Forms

Hypothetical Syllogism Mixed-up

Invalid Argument A → B A → C ∴ B → C If A, B If A, C Therefore, B equals C

Affirming the Consequent

Invalid Argument A → B B ∴ A If A, B B Therefore, A

Denying the Antecedent

Invalid Argument A → B ￢A ∴ ￢B If A, B Not A Therefore, not B

Disjunctive Syllogism Mixed-up

Invalid Argument A ∨ B B ∴ ￢A A or B B Therefore, Not A

Modus Ponens

Valid Argument A → B A ∴ B If A, B A Therefore, B

Hypothetical Syllogism

Valid Argument A → B B → C ∴ A → C If A, B If B, C Therefore A equals C

Modus Tollens

Valid Argument A → B ￢B ∴ ￢ A If A, B Not B Therefore, not A

Disjunctive Syllogism

Valid Argument A ∨ B ￢ B ∴ A A or B Not B Therefore, A