Argument forms: Deductive Arguments

What is the logical form of the following argument? If the Khmer Rouge are not led by Pol Pot, then the Khmer Rouge are led by Son Sen. The Khmer Rouge are not led by Pol Pot. So, the Khmer Rouge are led by Son Sen.

Modus Penons

Modus tellens

Valid Form; Denies part of the conditional L ⊃ T ~T ~ L conclusion denies conditional (usually)

What is the logical form of the argument below? We must vote our current representatives out of office if we disagree with their voting records. We disagree with our current representatives' voting records. So, we must vote them out of office.

affirming the consequent

Affirming the Consequent

affirms the consequent of conditional in another premise; invalid form A ⊃ B B // A conditional is conclusion

Is the argument below valid or invalid? If Jian isn't sick, then she doesn't need medication. If Jian doesn't need medication, she doesn't need to go to CVS. So, If Jian doesn't need to go to CVS, Jian isn't sick.

invalid

Affirming a Disjunct

invalid form; D ∧ S D ~ S

Denying the Antecedent

invalid form; similar to modus tellons; Antecedent is denied D ⊃ E ~D ~ E

Modus Ponens

valid argument; antecedent of the conditional is confirmed P ⊃ Q P // Q conclusion is antecedent

Disjunctive Syllogism

valid form; P ∧ Q ~ P //Q

Hypothetical Syllogism

valid form; hypotheticals "if"; The "middle man" can be removed p ⊃ Q Q ⊃R // P ⊃ R