SSH 105 Lecture Notes - Lecture 6: Deductive Reasoning, Logical Reasoning, Fallibilism

• School: Ryerson University
• Department: Social Sciences and Humanities
• Course: SSH 105
• Professor: Klaas Kraay

Document Summary

Valid or ii) invalid i) cogent or ii) non-cogent. Arguments that are invalid or not cogent are called ill-formed, since the premises do not guarantee that the conclusion is true or even probable. An invalid or non-cogent argument is automatically weak. Some common patterns of cogent arguments: most as are bs. Most professors have phds: x is an a 2. Therefore, probably, therefore, probably: x is a b 3. Kraay has a phd: x is an a 1. Kraay is right-handed: x is a b 2. Kraay is a professor: most abs are cs. Therefore, probably, therefore, probably: x is a c 4. Therefore, probably: president obama has ten legs. (from 1,2) This argument has two false premises and a false conclusion but, nevertheless, it"s what we call cogent. Because if the premises were true, the conclusion would be likely. One or more false premises, true conclusion.