*   starting to discuss Chapter 3 - Basic Logical Concepts

*   in this chapter, we'll discuss 2 kinds of classical
    logical arguments:

    *   deductive arguments
        *   conclusion is PROVED by the premises

        *   rigorous and inescapable, narrows the scope

        *   impossible to both ASSERT the premises AND
            DENY the conclusion

    *   inductive arguments
        *   conclusion is PLAUSIBLE or LIKELY because of the
            premises

        *   can be flawed, but widens the scope

        *   possible to assert the premises and deny the
	    conclusion (you can choose not to believe it)

*   we'll be discussing both types;

    here's a STARTING few ways to distinguish them:

    *   terms often found in deductive arguments:
        *   "certainly"
	    "definitely"
	    "absolutely"
            ...and other words that try to convey logical 
	       certainty

    *   some other CLUEs to recognize deductive logic:

        *   the strict necessity test:
	    *   if the conclusion follows with strict logical
	        necessity from the premises, then it should
		always be treated as deductive

        *   the common pattern test:
            *   if the pattern of the argument matches a
                well-known deductive logic structure or pattern
		of reasoning, then the argument is deductive

*   continuing (for a while) to FOCUS on deductive arguments:

*   FIRST, a few examples:

    EX. 1
    *   We are in Arcata.
    *   Arcata is in California.
        *   Therefore, we are in California.

    EX. 2
    *   The winner of the race gets the blue ribbon.
    *   Tim got the blue ribbon.
        *   Therefore, Tim won the race.

    EX. 3
    *   Either I walked here OR I rode an ox to get here.
    *   I didn't ride an ox to get here.
        *   Therefore, I walked here.

*   Some CLASSIC COMMON PATTERNS of DEDUCTIVE logic
    
    *   reminder: a conditional statement has the form:

        if A, then B

        ...where A and B are statements.

        *   the COMBO "If A, then B" is a SINGLE statement

        *   a conditional statement by itself is not an
	    argument

            ...but it sure might be a PART of an argument,
	    one of an argument's components;

    *   If A, then B.

        the A part is called the ANTECEDENT
	the B part is called the CONSEQUENT

*   Modus Ponens ("mode of AFFIRMATION")
    *   PREMISES:
        *   If A, then B.
        *   A is true.
    *   CONCLUSION:
        *   Therefore, B is true.

    *   also called "affirming the antecedent"
        because A is the antecedent of a conditional 1st premise
	and the 2nd premise asserts that A is true

*   Modus Tollens ("mode of DENIAL")
    *   PREMISES:
        *   If A, then B.
        *   B is NOT true. (also: B is false)
    *   CONCLUSION:
        *   Therefore, A must NOT be true. (also: Therefore, A is false)

    *   Also called "Denying the Consequent" -- because B is the 
        consequent in the 1st premise, and the 2nd premise asserts
	that B is false

*   Chain Argument
    *   PREMISES:
        *   If A, then B.
        *   If B, then C.
    *   CONCLUSION:
        *   Therefore, if A, then C

    *   3 conditional statements here!

*   by the way:
    syllogism: a 3-statement argument, with 2 premises and a conclusion

    *   the 3 patterns above are called HYPOTHETICAL syllogisms
        because they involve if statements/conditional statements

*   be careful, there ARE some NOT valid
    patterns of this style;

    NOT VALID: denying the antecedent

    If A, then B.
    A is false.
        Therefore,...?

	...no valid conclusion can be made about the value of B

    NOT VALID: affirming the consequent

    If A, then B.
    B is true.
        Therefore,...?

        ...no valid conclusion can be made about the value of A

*   there are some other classic syllogism forms:

    *   categorical - all, none, or some statements
    *   argument by elimination rules out possibilities
    *   mathmetical arguments
    *   argument from definition

    *   MORE on these,and deductive reasoning, on Monday