PHIL 1290 Lecture Notes - Lecture 6: Deductive Reasoning, Logical Reasoning, Logical Biconditional

• School: University of Manitoba
• Department: Philosophy
• Course: PHIL 1290
• Professor: Mark Rosner

Document Summary

If daisy is a dog, then daisy is nice. Either mark won the big game or joe won. Categorical arguments have to do entailment between classes or categories. Entailment turns on relations within propositions (terms that are expressed in statements) Example: 1) all mammals have lungs; 2) all whales are mammals; 3) all mammals have lungs. Propositional arguments have to do with relations between propositions ("eitheror"; "ifthen") that are truth preserving. So if an argument is valud, should we accept its conclusion. Our mistake: socrates never existed (plato made him up), so (2) is false. Argument is still valid, but one of the premises is false. Again, validity is not the same thing as truth. A good deductive argument is valid with true premises. When we have this we say the argument is sound. If lack either of these qualities, then argument is unsound.