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