Phil 105 Chapter 7

Don't criticize an Argument by denying its conclusion

Two Basic Ways an argument can go wrong: 1. Proposed reasons are not properly connected to the conclusion and the argument is ill-formed 2. Proposed reasons themselves are not worthy of our acceptance (if cogent argument, the argument is defeated by other evidence) - If argument is valid, the only criticism you can make of the argument is that it has at least one premise that is not reasonable to believe (false). You cannot criticize the argument by looking at the conclusion itself. - If argument is inductively cogent (argument is undefeated and premises are true), the only criticism you can make is the premise itself or show that the argument is defeated.

Semantic Ambiguity

When a sentence contains a word that is ambiguous and has different meanings depending on how that word is used.

Ambiguous

Where words have more than one meaning.

Syntactic Ambiguity

Words can be combined in different ways to form sentences with different meanings.

Vague

Words that have borderline cases of application.

Criticizing conditionals (If P then Q)

You must identify if the conditional has a sufficient condition or necessary condition.

Direct Criticisms at individual premises

- All criticisms of premises must apply to individual premises.

Dont Accept an argument simply because you believe the conclusion.

- If premises are unjustified or unreasonable to accept, then the argument is weak. - Judging the strength of the argument based on the truth of the conclusion itself is unreasonable.

Don't Object to Intermediate Conclusions of Compound Arguments

- In general, when dealing with compound arguments one can only justifiably criticize them as ill-formed or as having an implicit or explicit premise that is not worthy of acceptance. - It is never legitimate to criticize an intermediate conclusion directly. - To criticize an intermediate conclusion, there must be a flaw in the argument leading to it.

Criticizing disjunctions (P or Q)

- These arguments follow the pattern of "argument by elimination" - You can criticize this argument by looking for alternative options in a disjunction. If there are, you can reject the argument claiming that it is a weak argument because it contains an unjustified premise.

Make Your Criticisms of Premises Substantial

- To make criticisms substantial, just apply the principle of charity.

Incomplete Sentences: Missing Quantifiers

- When argument contain premises that are missing quantifiers, it is impossible to evaluate them. - To evaluate, supply a quantifier using the principle of charity.

Don't Accept Competing Arguments

- When one argument has a statement as its conclusion and another argument has the denial of that statement as its conclusion. - Both arguments cannot be rational for you believe. At least one of the argument has something wrong. If you cannot identify, it is best to suspend judgement. - A competing argument can both be weak however, and have ill-formed or have false or unjustified premises.

Criticizing conjunctions (P and Q)

- You can criticize the premise by criticizing P or Q individually.

Basic Rules of Argument Evaluation

1. Don't Criticize an Argument By denying its conclusion 2. Don't Accept an Argument Simply Because You Believe the Conclusion 3. Direct Criticisms at Individual Premises 4. Make Your Criticisms of Premises Substantial 5. Don't Accept Competing Arguments 6. Don't Object to Intermediate Conclusions of Compound Arguments

Insubstantial Criticism

A criticism that may appear to be significant but fails to identify a real flaw in the argument. (eg. Criticism that does not include reasons to think that the premise is false, or reasons to think that the suspension of judgment is the proper application towards a premise)

Counterexample

A criticism to an argument with generalization pointing out that there is not evidence supporting it. - Universal generalization are less effective to criticize

Incomplete Sentences: Implicitly relative

A sentence that make comparisons or describe relations between one thing and some unspecified comparison group or reference class. (eg. I am taller than average)

Argument Stoppers

A type of insubstantial criticism that cuts off rational discussion.

Equivocation

An argument that takes advantage of ambiguity.

Incomplete Sentences

An important element of the sentence goes unstated.

Type/token ambiguity

It is no clear whether the referent is a token (a specific instance of a thing) or a type (a kind of thing)

Grouping Ambiguity

It is not clear whether a group of things is to be taken individually or collectively

Necessary condition

One proposition, A, is a necessary condition for another, B, just in case if B is true, then A must be true as well.

Sufficient Condition

One proposition, A, is a sufficient condition for another, B, just in case if A is true, then B must be true as well. The truth of A is enough to ensure the truth of B.