Final Review

Argument – A set of claims put forward in an attempt to show that some further claim is rationally acceptable. Arguments are attempts to prove or justify a claim.

Conclusion – Claim or statement that is in dispute and that we are trying to support with reasons.

Premises – Claims that offer evidence or reasons intended to support the conclusion.

Extraction

1. Read the passage so that you understand it.

2. Make sure the passage contains an argument.

3. Locate the conclusion. If necessary, restate the conclusion in clear, simple language.

4. Locate the premises. If necessary, restate the premises in clear, simple language.

5. Re-read the passage to make sure that you have not misrepresented the author’s reasoning.

· Know the Standard Argument Form

Principle of Charity: When extracting an argument from a text try to do so charitably. Avoid attributing loose reasoning and implausible claims unless there is good evidence for doing so.

Other Parts of Arguments

· Conditional

· Subargument

· Lemma

· Hidden Premise

· Missing Conclusion

Issues of Scope

· All MSU students are smart and beautiful

· Most MSU students are smart and beautiful

· Many MSU students are smart and beautiful

· Some MSU students are smart and beautiful

Counterexample – A defeater. An exception to a proposed claim. The wider the scope, the easier it is to come up with a counterexample.

Ways That Premises Support Conclusions

By Linking – Linked premises can support the conclusion only when they are taken together.

By converging – Convergent premises are seen as each offering independent support for the conclusion

Two Ways to Evaluate an Argument

· Evaluate Premises

· Evaluate Reasoning from premises to conclusion

Cogent – An argument is cogent if i) the premises are rationally acceptable and ii) the premises provide rational support for the conclusion.

ARG Conditions

A – Acceptability of its premises. Premises are reasonable (may or may not be certain).

R – Relevance. Premises are relevant to the conclusion.

G – Grounds. Premises provide sufficient or good grounds for the conclusion.

Deductive Entailment – If a set of premises deductively entails a conclusion, then it is logically impossible for the premises to be true and the conclusion to be false.

Inductive Reasoning – We use inductive reasoning to make an inference from known cases to unknown cases. They predict the way the world will be (or sometimes retrodict the way it was).

Problems with Language

· Fallacy of Equivocation

· Vagueness

· Loaded Language

· Euphemism

Questions to Ask when Appealing Authority

· Is the authority a recognized expert in her field?

· Is the authority commenting on something in her area of expertise?

· Does what the authority says make sense?

· Do the authorities disagree?

When Are Premises Acceptable?

1. When they are supported by a cogent sub-argument

2. When they are supported elsewhere

3. When they are know a priori to be true

4. When they are matters of common argument

5. When they are supported by appropriate testimony

6. When they are supported by appropriate appeal to authority

7. When they are not known to be unacceptable (OK to accept them provisionally)

When Are Premises Unacceptable?

1. Statements that are couched in universal terms can be refuted by a counterexample

2. When they make claims that are known a priori to be false

3. When premises contradict each other

4. When the premises are vague

5. When the premises depend on a faulty assumption

6. When the premises are no more acceptable thathe conclusion

7. Fallacy of begging the question

When Are Premises Irrelevant?

Non-Sequitor – An argument in which the premises are irrelevant to the conclusion

Red Herring – A distracting remark that has no bearing on the discussion and tends to distract people from the main issue.

The Straw Man (Person) Fallacy – Criticize a weak position that your opponent does not really hold.

Ad Hominem Fallacy – Criticize a person’s background, personality, character or circumstances rather than the argument that the person has presented.

Guilt by Association – Criticize a person’s views on the basis of a supposed link between that person and a group or movement believed to be disreputable.

Fallacy of Appeals to Ignorance (Argumentum ad Ignoratium) – When the truth or falsity, probability or improbability of a statement S is inferred on the basis of ignorance, lack of confirmation or lack of proof of S.

Fallacious Appeals to Popularity (ad Populam Fallacy, Fallacy of Jumping on the Bandwagon) – When people seek to infer merit or truth from popularity.

Ad Misericordiam – Appeal to pity

Ad Baculum – Appeal to fear or force.

Necessary and Sufficient

If A, then B

A – Sufficient

B – Necessary

Example

If I am eating, then I am awake

· Knowing that I am eating is sufficient for knowing that I am awake

· Being awake is necessary for eating

Necessary but Not Sufficient for Being a Mammal

· Being warm blooded (birds are warm blooded)

· Having hair (spiders have hair)

· Breathing through lungs (reptiles do too)

· Possessing a heart

· Made of matter

Sufficient but not Necessary for Being a Mammal

· Having live births (platypuses don’t)

· Being a human

· Being a dog

Deductive Reasoning

Categorical Logic – A branch of formal logic in which the basic logical terms are all, some, no, are, and not.

Propositional Logic – Deals with the relationships that hold between simple propositions or statements and their compounds. The basic logical terms are not, or, and, and if then.

Modus Ponens

If A, then B

A

Therefore, B

Modus Tollens

If A, then B

Not B

Therefore, not A

One Person’s Modus Ponens is Another Person’s Modus Tollens. Example: If there is a God, then, given his benevolence, this is the best of all possible worlds

Logical Connections for Propositional Logic

Not – Negation

P or ~P is a tautology

And - Conjunction

If P & Q, then P, and Q. Both P and Q must be true for P & Q to be true. P & Q needn’t be related to each other

Or - Disjunction

Inclusive Disjunction: True either when one disjunct is true or when both disjuncts are true.

Exclusive Disjunction: True when only one disjunct is true; false when both disjuncts are true.

Conditionals

Antecedent – The hypothesized statement

Consequent – What is supposed to follow from the antecedent

A conditional is false only when the antecedent is true and the consequent is false

Valid Argument Forms

Modus Ponens

If P, then Q P ---- Q

P If P, then Q ----- Q

Modus Tollens

If P, then Q ~Q ----- ~P

If ~P, then ~Q Q ----- P

Hypothetical Syllogism

If P, then Q

If Q, then R

-----

If P, then R

Disjunctive Syllogism

P or Q ~Q ----- P

P or Q ~P ----- Q

Invalid Argument Forms

Denying the Antecedent If P, then Q ~P ----- ~Q

Affirming the Consequent If P, then Q Q ----- P

Counterfactuals
E.g., If I had gone to the party I would have had a good time. Not well represented by the material conditional.

Inductive Reasoning

Use inductive reasoning to make an inference from known cases to unknown cases. Sometimes in order to predict the way the world will be, sometimes to retrodict the way it was.

Three Types of Inductive Arguments

· Inductive Generalizations

· Causal Inductive Arguments

· Inductive Analogies.

Problem of Induction (David Hume)

P1) Every day that I can remember the sun has risen.

C) Therefore the sun will rise tomorrow.

The argument can only be made valid if you include a premise asserting that the future will resemble the past (but this premise is justified on inductive grounds).

Samples

Random Samples - A sample is random if every member of the population has an equal change of being chosen for it.

Stratified Sample – In a stratified sample the population is divided into large subgroups, then every effort is made to ensure that the sample has the same proportion of representation of each subgroup as the population as a whole.

Variability - The smaller the variability the smaller you need your sample size to be.

Biased Samples – A sample is biased if it does not adequately represent the population.

Causal Inductive Arguments

We say that A causes B when:

i) A is a necessary cause of B (dry forest conditions are necessary for forest fires)

ii) A is a sufficient cause of B (the lightning that struck the tree was sufficient, given the background conditions, to start the fire)

iii) A is both a necessary and a sufficient condition for B (entire causal history is given)

iv) A is a contributing factor of B (forest fired caused by a failure to apply forest management techniques).

Correlation is not the same thing as causation.

· Correlation has to be significant

· Can have correlation without causation

Argument for Causation

P1) C and E are regularly associated events

P2) C regularly occurs before E

P3) The claim that C is a cause of E is consistent with background knowledge about C and E

C) Therefore, probably C is a cause of E

Fallacies of Inductive Reasoning

Hasty Generalization – Making an inference from a hopelessly inadequate sample. For example, generalizing from anecdotal evidence.

Post Hot Fallacy (Post hoc ergo propter hoc, after this, therefore because of this) – Inferring that A caused B because A came before B.

Fallacies of Composition and Division – Attributing to the whole what is true of the part, or to the part what is true of the whole.

Objectionable Cause – Arguing for a causal interpretation on the basis of limited evidence, with no attempt to rule out alternative explanations.

Causal Slippery Slope Arguments – A proposed action is wrong because it would set off a series of side effects, ending ultimately in general calamity.

Analogy

An analogy is when you draw a conclusion about one thing on the basis of a comparison of that thing and another.

· Primary subject – Subject you want to draw a conclusion about

· Analogue – Analogous case

A priori Analogies – Used to support a decision to treat relevantly similar cases the same way (morally, legally, logically, or administratively). The analogous case needn’t be real.

Inductive Analogies – Used as a basis for prediction. The analogous cases must be real.

To Evaluate Analogies

1. Are the similarities significant?

2. In inductive analogies, are the facts genuine and the similarities numerous?

3. To refute an analogy find differences that are negatively relevant to the conclusion. Use background knowledge

Writing A Persuasive Essay

· State a main point or claim.

· Present arguments for your claim.

· If relevant, state any objections to your claim (and defeat the objections).

· Signpost: Tell the reader how you are arguing (or how you have argued), and what you’ve left out. If an argument structure is complicated, go over the steps.

· Avoid “naked this” – Using a “this” with an uncertain referent, as in “this shows that my opponent’s argument is entirely wrong.”

Counterconsiderations/Objections – An issue in the case of converging arguments. Points that are negatively relevant to the thesis. Introduced by words like although, even though, despite the fact that, and notwithstanding the fact that.