PHL 214 Lecture Notes - Lecture 6: Modus Ponens, Logical Reasoning, Modus Tollens

• School: Ryerson University
• Department: Philosophy
• Course: PHL 214
• Professor: Thomas Land

Document Summary

Deductively valid if and only if it is not possible for the premises to be true and the conclusion false. Sound if premises are true and argument is deductively valid. Inductive is not as conclusive- strong if and only if given premises are true, conclusion is likely to be true. Cogent if inductively strong and premises are true. Valid conditional argument: affirming the antecedent (modus ponens, denying the consequent (modus tollens, hypothetical syllogism. Invalid conditional argument: denying the antecedent, affirming the consequent. If tuition fees continue to rise, i won"t be able to afford school. I"m telling you: school will soon be affordable. If atheism is true, there would be no such thing as objective right and wrong. I was in jail when he was killed! . To find implicit premises: search for a credible premise that would make the argument deductively valid.