PHIL 230 Introduction to Philosophical Methods Arguments PDF

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Intro to arguments in philosophy...

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PHIL 230 Introduction to Philosophical Methods: Arguments ARGUMENT - Main thing philosophers do - “Any academic argument” - Not a mere verbal fight or disagreement - Disagreement + reason to believe your claim - Conclusion + reason for argument = argument - Must have at least 1 premise to be an argument EXAMPLE 1 1. All apples are composed of organic molecules 2. Red Delicious Apples are apples C. Red Delicious Apples are composed of organic molecules

VALID

EXAMPLE 2 1. Only those who have matriculated at Cal Poly can register for Cal Poly courses 2. Todd Long has matriculated at Cal Poly C. Todd Long can register for Cal Poly courses

INVALID

INDICATORS Conclusion indicators: therefore, hence, thus, consequently, it follows that, ergo Premises indicators: because, since, given that, due to, for the reason that BE MINDFUL - Some people forget their premises or a stated conclusion - Neither premises or conclusions - Clearly state your premises and conclusions, make it easy to read VALIDITY TEST - “Valid” = true, agreed upon, sensible, logical, reasonable - An argument is valid if AND ONLY if, the truth of the premises show logical truth, then the conclusion is logically true - Premises can’t be valid, they can be T/F - Validity is a factor for arguments 1. Assume all premises are true 2. Holding fixed at assumption, ask: a. “Is it possible for the conclusion to be false?” i. If “yes”, then the argument fails the test (invalid argument) ii. If “no”, then the argument passes the test (valid argument) * You can test validity without understanding the premises 1. All trucks are cats 2. George Bush is a truck C. George bush is cats

Valid but not true

PHIL 230 Introduction to Philosophical Methods: Arguments CONCLUSIVE PREMISES TEST 1. Ask: Do I have a reason to believe each premise? a. If ‘yes’ = step 2 b. If ‘ no’ = argument fails the test 2. Ask: Do I have a reason to disbelieve any premise> a. If ‘yes’ = argument fails b. If ‘no’ = argument passes the test - Don’t believe anything until you have a reason to - Understand each premise exactly - A premise can pass the conclusion premises test and still be invalid - When we think the conclusion is false, we should not automatically assume that it’s false - Argument has to pass both tests to be valid - Valid ≄ conclusion is true - Premise true ≄ argument is valid VALIDITY TEST - Tests logical structure - If premises are true, is the conclusion true? - The truth of the premises = the truth of the conclusion - It’s impossible for the premises to be true and the conclusion false

CONCLUSIVE PREMISES TEST - Testing truth value of premises - Are the premises true?

PREDICATE LOGIC All As are Bs X is an A --X is a B *Both are valid

SENTENTIAL LOGIC If P, then Q P --Q

DEDUCTIVE ARGUMENTS - Deduction - Purports to demonstrate (to prove in the strongest sense) that its conclusion is true, and thus to make its conclusion reasonable to believe - Math and philosophy

INDUCTIVE ARGUMENTS - Induction - Purports to make probable its conclusion and thus to make its conclusion reasonable to believe - Science

DOXASTIC ATTITUDES - Belief - Disbelief - Suspension of judgement...