Chapter 3

Chapter 3

1. 2 Forms of Arguments

   • Deductive arguments: logically conclusive support for its conclusion; conclusion is either true or false
     • Classifications
       • (1) Valid Argument: provides conclusive support for its conclusion. Can have true or false premise and true or false conclusions. *CANNOT have true premises and false conclusions.
         • Truth-preserving: guarantees truth of the conclusion if the premises are true.
         • (Sound: Has true premises. A good argument that gives you good reasons for accepting its conclusions.
       • (2) Invalid Argument: does not provide conclusive support for its conclusion.
     • Indicators: It necessarily follows that, It logically follows that, Absolutely, Necessarily, Certainly
     • If p, then q.p. Therefore, q.
   • Inductive; capable of providing only probable or non-probable support for its conclusion
     • Strong Argument: provides probable—but not conclusive--- support for its conclusion. (Cannot guarantee that the conclusion is true)
       • Cogent Argument: strong inductive argument with all true premises; AKA Good Inductive Argument
     • Weak Argument: doesn't provide strong support for its conclusion.
     • Indicators: Likely,Probably, Chances are, Odds are, It is plausible that

2. 4 TIPS TO EVALUATE AN ARGUMENT:

   • 1. Find Conclusion then Premises
     • "If the premises are true the conclusion must be true?”
       • Yes, then treat the argument as deductive. The argument then is deductively valid, and you should check if its sound. If no, proceed to the next step.
         • “Is it the case that if the premises are true its conclusion is probably true?” If yes, treat the argument as inductive. The argument then is inductively strong and you should check to see if its cogent. If the answer is no, proceed to the next step.
           • “Is the argument intended to offer conclusive or probable support for its conclusion but fails to do so?” (If you reach this step you will have either an invalid deductive argument or a weak inductive argument).