Reasoning and Logic

how is deductive reasoning usually demonstrated?

in the form of a syllogism

ethical appeal

use value or moral standards that are widely accepted as a way to persuade an audience

Appeal to false authority

when someone has no expertise to speak on an issue is cited as an authority (think celebrity endorsements)

begging the question EXAMPLE

giving students easy access to a wealth of facts and resources online allows them to develop critical thinking skills. (this statement presupposes that students will in fact use the online resources and that by using them critical thinking skills will naturally develop)

false analogy example

government like a business should be focused on the bottom line

Pathos

(emotional appeal) emotional manipulation; appeals to the reader's needs, desires, and wishes

Logos

(emotional appeal) evidence taken from either statistics or expert testimony

Ethos

(writer credibility/authority) (ethical appeal) consists of the writer's competence, good will, and character

Requirements for inductive reasoning (3)

1. Generalization must be based on sufficient evidence 2. Evidence must be drawn from a random sampling 3. Generalization must explain all of the evidence

requirements for deductive reasoning (3)

1. both premises must be true 2. generalization must make universal statement 3. specific example must be subject of the first premise

False cause (post hoc ergo propter hoc) Origin

Latin for "after which therefore because of which"

Ad hominem

Latin for "against the man"; refers to the specific diversionary tactic of switching the argument from the issue at hand to the character of the other speaker

straw man example

Senator Jones says that we should not fund the attack submarine program. I disagree entirely. I can't understand why he wants to leave us defenseless like that.

Circular reasoning

a fallacy in which the writer repeats the claim as a way to provide evidence ("you cant give me a C; I'm an A student")

Hasty Generalization

a faulty conclusion is reached because of inadequate evidence

Deductive Reasoning

a logical process whereby one reaches a conclusion by starting with a general principle or universal truth (major premise) and applying it to specific case (minor premise)

Inductive Reasoning

a logical process whereby the writer reasons from particulars to universals, using specific cases in order to draw a conclusion, which is also called a generalization

Argument

a process of reasoned inquiry; a persuasive discourse resulting in a coherent and considered movement from a claim (thesis) to conclusion

claim of value

argues that something is good or bad, right or wrong

Syllogism

argument with a major and minor premise

Stereotype

asserts that all members of a particular group share certain characteristics (usually negative)

claim of fact

asserts that something is true or not

Begging the question

assumes as evidence that which you are trying to prove. it "begs a question whether the support itself is sound (the evidence or support is in doubt)

stereotype example

dumb jock/blonde, etc.

either/or example

either we agree to higher taxes, or our grandchildren will be mired in debt

parts of rhetoric (3)

ethos pathos logos

Origins of inductive reasoning

from the Latin inducere - "to lead into"

how does a claim differ from a topic or subject?

it has to be arguable

hasty generalization example

it is extremely dangerous to drive in New York; the one time I was there I got into an accident

False cause definition

it is incorrect to always claim that something is a cause just because it happened earlier; correlation does not imply causation (think superstitions)

persuasive techniques (3)

logical appeal emotional appeal ethical appeal

deductive reasoning example

major premise: exercise contributes to better health minor premise: jogging is a type of exercise conclusion: jogging contributes to better health

Ad populum (bandwagon appeal)

occurs when evidence boils down to "everybody's doing it, so it must be a good thing to do"

emotional appeal

presents ideas and images that elicit strong feelings

claim of policy

proposes a change

Inductive reasoning example

regular exercise promotes weight loss exercise lowers stress levels exercise improves mood and outlook generalization: exercise contributes to better health

logical appeal

rely on fact and logic to support a claim

Claim (aka assertion/proposition/thesis)

states the argument's main idea or position

False cause example

the one time I forgot to wear mu lucky socks we lost the game

Either/or (false dilemma/choice)

the speaker/writer presents two extreme options as the only possible choices, when in fact other choices are available (often appeals to fear)

Straw Man

when a speaker/writer chooses a deliberately poor or oversimplified example in order to ridicule and refute an idea

False analogy

when an analogy compares two things that are not comparable