Critical Thinking and Reasoning

Critical Thinking and Reasoning Dr. Philipp Dorstewitz (AURAK)

Introduction: critical reasoning

Week 1 Meeting 1…

“

• Nearly all those surveyed (93%) agree, “a candidate’s demonstrated capacity to think critically, communicate clearly, and solve complex problems is more Important than their undergraduate major.” • More than nine in ten of those surveyed say it is important that those they hire demonstrate ethical judgment and integrity; intercultural skills; and the capacity for continued new learning. • More than three in four employers say they want colleges to place more emphasis on helping students develop five key learning outcomes, including: critical thinking, complex problem-solving, written and oral communication, and applied knowledge in realworld settings.”

”

From: It take more than a major - Employer Priorities for College Learning and Student Success An Online Survey Among Employers Conducted On Behalf Of: The Association Of American Colleges And Universities By Hart Research Associates (2013), Hart Research Associates

• • • • • • • • • •

What is reasoning? Is it the same for every body/culture/historical period? Are you sufficiently reasonable? And, Is there a simple yes or no answer on “are you reasonable”? Where and when do you use reasoning? What is being critical?

Questions week 1 meeting 1

“

Good sense is, of all things among men, the most equally distributed; for every one thinks himself so abundantly provided with it, that those even who are the most difficult to satisfy in everything else, do not usually desire a larger measure of this quality than they already possess. And in this it is not likely that all are mistaken the conviction is rather to be held as testifying that the power of judging aright and of distinguishing truth from error, which is properly what is called good sense or reason, is by nature equal in all men;

Rene Descartes

”

• • • • • • • • • • • • • • • •

SLO 1 Understand the major concepts of reasoning, the features of an argument and the ability to represent them. SLO 2 Critically examine and analyze written and spoken arguments. SLO 3 Distinguish between good and bad reasoning, credibility of sources, plausibility of claims and to identify fallacies in reasoning. SLO 4 Compare, assess and use inductive and deductive reasoning. SLO5 Prepare and present arguments supporting or against propositions.

Student Learning Outcomes

• • • • • • • • • •

Week 1 Introduction: reason and argument Week 2 Arguments Week 3 Obstacles to critical thinking/the environment of critical thinking Week 4 Intercultural dialogue Making sense of arguments

Course Plan (1)

• • • • • • • • •

Week 5 Diagramming arguments Reasons for belief and doubt Week 6 Faulty reasoning Week 7 Deductive reasoning: propositional logic Week 8 Review and midterm exam

Course Plan (2)

• • • • • • • •

Week 9 Appeal to Experts and Epistemic Justice Week 10 Inductive Reasoning Week 11 Inference to the Best Explanation Week 12 Judging Scientific Theories

Course Plan (3)

• • • • • • • • • • •

Week 13 Judging Moral Arguments and Theories Week 14 TBA Week 15 Course Review Week 16 Final Exam

Course Plan (4)

GradingPlan: Methods

Week

Weights

Class Participation & Quizquestions

20%

Assignments

30%

Mid-TermExam

8

20%

Final Exam

16

30%

Argument: why does critical reasoning matter

Week 1 Meeting 2

• • • • •

Why does critical thinking matter? How does critical thinking relate to logic? Where is critical thinking needed? Can we be too critical? And what does this mean? What is a statement? What is an argument?

Questions week 1 meeting 2

• Beliefs are not really yours if you just receive them. • Often reasons presented to you represent someone else’s interest (you want to look through the game) • Without CR your opinions are like leaves in the storm. You can easily be manipulated • Examine beliefs means to examine your life! (Socrates: “an unexamined life is not worth living”)

Importance of critical thinking

• Logic is constitutive of critical reasoning • Violations of logical rules mark the breakdown of critical reasoning • But critical reasoning is not merely the application of logical rules. It is a creative process • There can be critical reasoning about the rules of logic (philosophy of logic)

CR and Logic

• It is cold, calculating and emotionally aloof!? • It stifles spontaneity!? • It undermines creativity!? • It suppresses intuition and gutfeelings!?

Critique against critical reasoning

 Perhaps critical reasoning can be seen as complementary to these capacities and support rather than undermine all dimensions of human intelligence!? Discuss!

• • • • •

Appeal to tradition (prioritising the past over the future) Authority (often force or threat implied) Following role model (e.g. celebrities) Adapting to common views (following the crowd) Giving way to reflexes and unqualified emotions (e.g. greed, panic etc.) • …

Some alternatives to critical thinking

• When a point is clarified or proof is given sufficiently (mathematical proof) • When parties have hammered out an agreement (business or diplomatic negotiations) • When time is up or third party intervenes (election campaigns, court cases, ultimatum situations) • When context changes (debate on whether US should enter 2 nd word war after pearl harbour) • Some go on forever (e.g. philosophical debates: do we have a free will or are all our actions determined by causes – has occupied minds for over 3000 years)

When does an argument come to an end?

What is an argument

Week 2 Meeting 1

• What is the standard form of an argument? • What are the elements of an argument? What are their relations? • How do arguments get undermined? • How do we recognise an argument?

Questions: week 2 meeting 1

• Statement: declarative sentence that can be true or false (proposition)

Statement

• Common use: verbal dispute, conflict, bickering • Our sense: a connected set of sentences proposed with the intention of supporting a claim as a conclusion

2 senses of “argument”

• Claim! • Premises (propositions), • Warrants (“inference tickts” – often counted among premises)

Elements of an argument

• Premise(s) • Warrant(s) • Conclusion

Standard form of an argument

Arguments in reasoned dialogue

Week 2 Meeting 2

• What types of dialogue can you distinguish? • Which typical fallacies occur in dialogues? • What are the regular components of argumentative dialogue? • How can we persuade through critical discussion? • What rules do we have to follow in dialogue?


• Procedural rules (more or less codified rules) • Locution rules (what diction, utterances and propositions are deemed apposite) • Commitment rules (which arguments do have to be taken serious? Self-contradictions cannot stand)

Rules of argumentation

• Opening stage rule: how to define a topic and how to set an agenda • Argumentation stage: e.g. relevance, informativeness • Closing stage: .e.g. who gets the last word; what can be left for future debate

Rules pertaining to stages of argumentation

• • • • •

It is is about content and structure Rhetoric Psychology (feelings, prejudices, trust, authority) It addresses background assumptions It is pitched at an audience and its level of education and expectation • It takes a position respective the larger context of a controversy

Good argumentation is more than mechanically following a scheme…

Obstacles to critical thinking/ The environment of critical reasoning

Week 3

The perils of mind and group think

Week 3 Meeting 1

• • • •

What limits or impedes critical thinking? Name a few common fallacies? How do we detect errors in our thinking? What tricks does our mind play on us when it comes to critical and rational thinking? • How can group thinking and group pressure (peer pressure) distort our judgment?


• Pejorative (negatively valued) term • Refers suboptimal deliberation and decisionmaking by groups • Groupthink decision-making can be inefficient, ill-informed, irrational – even disastrous • Group-think can lead to worse decision-making than what might be expected of any groupmember individually

Groupthink

• • • • •

Overestimation of the group’s rationality and wisdom Illusory believe in the group’s power and efficacy Blind trust in the group’s moral righteousness Narrow-mindedness and prejudice Conformity, censorship and mind control

Types of Groupthink

• • • • •

The bay of pigs invasion Pearl Harbor Suisse Air British Airways Marks & Spencer

Famous examples of groupthink desasters

• • • • •

Steep hierarchies Communication barriers between hierarchy levels Stereotyping and exclusion Self-censorship Mind-police (self-appointed guards of the right group ideology

Indicators of groupthink

• Insulation of the group • Deindividuation (prioritization of group cohesiveness over individual freedom and expression) • Homogeneity of group-members • Steep hierarchies • Stress, panic, time-pressure • Moral dilemma

Contributing factors

• • • •

Ad bacculum (appeal to force) Ad populum (appeal to public opinion Ad misericordiam (appeal to pity) Ignoratio elenchi (irrelevant conclusion)

A Few Fallacies

Worldviews and language

Week 3 meeting 2

• Can you critically reason about your own worldview? • Are there subjective truths (name and explain some candidates)? • Why does Vaughn believe all forms of relativism are selfdefeating? • What is the difference between “being beyond possible doubt” and “being beyond reasonable doubt”? • How can we do things with words, and what can we do with words? • Does reality depend on language?


• Declares every person his or her own authority on matters such as morality, knowledge or reality • Truths (moral and epistemic) depend solely on the judgments of the subject.

Subjective Relativism (candidates of subjective truths)

• Moral relativism: the authority of moral norms depends on cultural practices and the believes of a moral community. They may have no authority beyond the boundaries of a cultural community that embraces them • Epistemic relativism: beliefs about the world depend on cultural patterns of judgment and recognition. Even perception is conditioned by culture • Metaphysical relativism: reality itself depends on (arbitrary) cultural constructions

Cultural relativism

• • • • • • • •

Internal sensations (toothache, pleasure, thirst, nausea) Feelings/emotions (love, excitement, resentment) Tastes (preferences) Perceptions/experiences (the stick is bent in the water) Values (the importance of being faithful) Beliefs (existence of guardian angels) Reality (are there nine planets?) Definitions (is a dolphin a fish? Was the attack on the world trade Center one or two events?)

Candidates for subjective, objective or intersubjective categories

• It leaves no possibility of being wrong in inter-subjective or intercultural comparison • Subjective relativism leaves no room for the difference between moral norms and tastes • Cultural relativism leaves no room for distinction between cultural and moral norms (e.g. between rules of politeness and human rights) • Relativism can be self-defeating (if relativism is presented as a universally valid theory)

Problems with relativism

• Locution (expressing sense, meaning) • Perlocution (exerting a causal power) • Illocution (changing a status of someone/something by means of an utterance)

Speech acts (John AUSTIN)

The logic of intercultural dialogue

WEEK 4 Meeting 1

• How does Parekh define “operative public values” in a society (give examples)? • Which stages do intercultural conflicts normally go through according to Parekh? • What can a dominant local culture expect from cultural minorities? • Can value conflicts be beneficial for any culture? • How should we conduct dialogue with members of different cultures?


• Reference to universal values (human rights, liberal principles, equality) • Shared values (values that are historically acquired and embedded in practices) • No harm-principle (interference is allowed if and only if someone gets harmed) • Open-minded intercultural dialogue (involving representatives and spokespeople)

4 ways of addressing value-conflicts

• Constitutionally enshrined values • Laws • Civic values and customs

Operative public values (Parekh)

1. defense appeals to cultural authority 2. defense appeals to deep meaning and connection with practice 3. Step beyond confines of culture: appeal to wider social values

Which stages do intercultural conflicts normally go through according to Parekh?

• Not to undo the fabric of the majority culture • Although majority has an obligation to accommodate minorities, this does not hold at any cost • Minority culture that is unfamiliar with local customs must gracefully submit to the majority

What can a dominant local culture expect from cultural minorities?

• Challenge views (to overcome or to invigorate them) • Inspire and enrich an existing culture • Trigger implicit internal processes of reorienation

Potential benefits of cultural conflicts

“Tradition is passing on the flame, not worshipping the ashes”

Gustav Mahler

Making Sense of Complex Arguments

Week 4 Meeting 2

• What is a valid argument? • What is a sound argument? • Can a valid argument have true premises and a false conclusion? • Can it have false premises and a true conclusion? • What is a cogent argument? (Give an example) • What is a strong argument?


• True or • False

Statements can be

• Valid or invalid • Sound or unsound • Cogent or not cogent

Arguments can be

• Refers to the relation between the premises and the conclusion of an argument • It points at how well the premises support the conclusion • Validity is only concerned with the structure of the argument (not with the content or the truth or falsity of any sentence)

Validity

• Establishes ONLY one thing: if the premises are true then the conclusion is true, and nothing else…

Validity

• True premises and true conclusions • False premises and false conclusions • False premises and true conclusions

Valid arguments can have…

• True premises and false conclusions

But never….

• People with red hair and light skin burn easily in the sun. • Philipp has red hair and light skin • Therefore Philipp burns easily in the sun

True premises and true conclusion

• Dolphins are fish • All fish have tailfins • Therefore Dolphins have tailfins

False Premise true conclusion

Passing this course takes 10 minutes of preparation; I have studied for 10 minutes while driving to class Therefore I will pass the course!

False Premise false conclusion

• If A then B • A is indeed the case! • Therefore B

Modus Ponens

• If A then B • A is not the case! • B is not the case

Fallacy (of denying the antecedent)

• If you get an A in all subjects you will be set for a rocketing career • You have only achieved B’s and C’s • Therefore you will not have a rocketing career!?

Example

• If A then B • B is the case! • Therefore A is true….

Fallacy (of affirming the consequent)

• If it rains the street gets wet • The street is wet • Therefore it must have rained

Example

• If A then B • B is not the case! • Therefore A is not the case!

Modus Tolens

• If you study, you pass the course • You did not pass • Therefore in can be concluded that you did not pass!

Example

• • • •

Valid  Sound Strong Cogent

Arguments

• It is valid and • All its premises are true

An argument is sound if and only if …

• Deductive – arguments give conclusive support to a claim, i.e. conclusion follows with necessity, given the premises • Inductive – arguments gives support to a conclusion only with a degree of probability

Deductive vs. inductive arguments

The premises support the conclusion (analogue to valid)

An (inductive) argument is strong if and only if

• If it is strong and • If it has true premises

An (inductive) argument is cogent if and only if…

Understanding and diagramming complex arguments

Week 5 meeting 1

• • • • • • • •

Examples Images Ideas Descriptions Background information Illustrations Irrelevancies Etc. etc….

What does (persuasive) text contain besides arguments

1. 2. 3. 4. 5. 6. 7. 8.

Make sure you understand the argument Identify conclusion (claim) Identify premises Fill in gaps and delete irrelevant parts Determine if it is deductive or inductive Evaluate it’s validity (or strength) Evaluate it’s soundness (or cogency) Draw a diagram or the argument’s structure

Steps in analyzing arguments

“If you don’t get out of the house now you won’t catch the 9:23 bus. You will be late, and this will be probably the last time you get away with it. You boss is definitely going to raise the issue of your work attitude again and you can forget about your promotion. …o.k., it is 9:40 now, so forget about a career in your current job.”

Analyze the structure…

Sequential structure (dependent)

“AURAK is developing into full-grown university of international standing at a remarkable speed. Student numbers have more than doubled in two years; as of this year AURAK offers 14 new degree programs; more than 20 international academics have recently joined; MBA programs have been approved, and our library resources have considerably augmented; the PhD program is outstanding…”

Argument

Argument

Argument

Argument

Resolution / Main claim

Convergent structure (cumulative/semi-dependent)

“He ruled the Congo Free State … as a personal domain. His men tortured, maimed, and slaughtered millions of Congolese. Congolese were killed if they did not bring enough rubber. Hundreds of thousands of people had their hands, legs, feet, arms, heads, ears, and noses cut off. Many villages were burned... Leopold’s men raped [and] flogged natives. They slaughtered hundreds … of children.”

Leopold II of Belgium was an evil King (from http://25mostevil.wordpress.com/)

Argument

Argument

Argument

Argument

Resolution / Main claim

Parallel structure (independent arguments)

“This ring is made of gold. Since gold conducts electricity, this ring will too”

Please draw a diagram

This ring is made of gold

Since gold conducts electricity, this ring conducts electricity too

Like so???

?

This ring is made of gold

Gold conducts electricity

This ring will conduct electricity

Better

Premise: This ring is made of gold

Warrant: Gold conducts electricity

Conclusion: This ring will conduct electricity

Best (Toulmin model)

Reasons for Belief and Doubt: personal experience and fooling ourselves

Week 5 Meeting 2

1. 2. 3. 4. 5. 6. 7. 8.

Make sure you understand the argument Identify conclusion (claim) Identify premises Fill in gaps and delete irrelevant parts Determine if it is deductive or inductive Evaluate it’s validity (or strength) Evaluate it’s soundness (or cogency) Draw a diagram or the argument’s structure

Steps in analyzing arguments (reminder)

“The use of a growing array of derivatives and the related application of moresophisticated approaches to measuring and managing risk are key factors underpinning the greater resilience of our largest financial institutions ... Derivatives have permitted the unbundling of financial risks.”

Alan Greenspan (2005)


Steps 1 & 2


Step 3


Step 4

Premise: Financial institutions use a growing array of derivatives Warrant: derivatives help unbundling financial risks, and thereby help resilience

Banks today are more resilient

Step 5 (Diagramming)

Financial institutions use a growing array of derivatives Explicit: Derivatives help unbundling financial risks

Financial institutions have unbundled their risk Implicit: Unbundling financial risks increases resilience Banks today are more resilient

Alternative

More sophisticated methods of measuring risks

Financial institutions use a growing array of derivatives Derivatives help unbundling financial risks

Better risk management Financial institutions have unbundled their risk

Unbundling financial risks increases resilience Banks today are more resilient

Complete…

• • • •

Direct method 1: attack the premise Direct method 2: attack the reasoning Indirect method 1: attack conclusion Indirect method 2: use analogous argument to show that original argument is poor

Four ways to attack an argument (LAU)

• We have seen an increase of derivatives • Derivatives help unbundling risks (and thereby increase the resilience of financial institutions) • Derivatives helped increasing the financial resilience of big financial institutions.




Week 5 meeting 2

• • • •

What are the sources of personal knowledge? How reliable are they? Is our memory true to the facts? What is the problem with confirmation bias and how can we help resisting it? • Can we guard ourselves against manipulation (e.g. by the media)? If so how?


• Perception: acquaintance of the world through senses • Memory: records of experienced events and encoded knowledge • Judgment/Reasoning: augmentation of knowledge and orientation through conclusive mental operations

Sources of personal knowledge

Perception

• Murder mystery: http://www.youtube.com/watch?v= ubNF9QNEQLA • Person swap: http://www.youtube.com/watch?v=QbgT6vDrmU

Change blindness

• False memories (simple mistake) • “Recovered” memories (psychoanalysis) • Memory by association (e.g. manufactured laboratory memory: though suggestive context information) • Confabulation (imaginative filling of memory gaps)

Memory or false memory?

• Would you buy a car radio for 1600 Dirham? • Would you prefer a car with a radio for 95000 Dirham? Rather than on without for 93400Dirham?

Judgment: Framing

• 93 % of students registered early when penalty fee for late registration was emphasised. Only 67 % when it was presented as a discount for early registration…

Judgment: Framing

Week 6 Persuasion, Manipulation and Fallacies Meeting 1: Bias Manipulation

• Murder mystery: http://www.youtube.com/watch?v= ubNF9QNEQLA • Person swap: http://www.youtube.com/watch?v=QbgT6vDrmU

Recap: Change blindness

• What are the problems of “resisting contrary evidence” and “confirmation bias”? • How can we guard ourselves against them? • What reasons do we have to read/watch news with critical attention? • What means does the advertising industry have to persuade or manipulate us? • Can we resist persuasion and manipulation (by the media or the advertising industry)? If so, how?


• Evidential bias: misapplying critical standards for revising or confirming beliefs • Context bias: being swayed by the context or presentation of an issue • Ego bias: Over (or under-) estimating ones own capacities • Memory Bias: typical misrepresentations of reality due to the structure and encoding of memory

Cognitive Bias

• Confirmation bias: we tend to interpret new information as confirming our existing beliefs; • Resistance to contrary evidence: we give undue recognition or treatment to evidence counterviewing our beliefs

Evidential Biase

• We read existing experience as evidence for our view • We select sources of information that support our convictions

Confirmation Bias

• We sometimes ignore or dismiss contrary evidence (e.g. “this is just liberal garble and communist propaganda”) • We give it unduly severe scrutiny (e.g. we demand more evidence, criticize methodology, dismiss examples as anecdotal and not representative, or we demand proof instead of good support) • We sometimes interpret contrary evidence to support our claim

Resistance to contrary evidence

• Anchoring: setting an arbitrary reference point. Judgment uses this as a basis for adjustments • Framing…see previous week • Sensual experience: e.g. light, smell, color, music, e.g. hotels employ designers for the smell of their lobbies

Context biases

• Most people think their kids are above average • Most people think they are more intelligent than their peers • More than 50 % believe they drive more securely when they had alcohol • People regularly overestimate how popular they are

Ego biases

• People think emotional or dramatic events are more likely • They give more weight to firsthand experience than statistics • Imagining an outcome makes us think it is more likely to happen • People respond more positively to familiar things • Recent experiences have a greater impact than earlier ones

Memory Biases (J.Lau)

• Enhance awareness: Learn about these biases and their causes • Think critically! Careful and systematic reflection helps discovering biases • Seek feedback and criticism. Don’t be too proud or resistant • Take other points of view: try to see the world through the eyes of another • Widen your sources of information

Combating cognitive biases (Lau)

Germans were in average better at telling whether San Diego or San Antonio is bigger than Americans! Why? Because more Germans had only ever heard about San Diego and never of San Antonio than vice versa….

Can we exploit ignorance and biases? Recognition heuristic

• To persuade: to cause someone to believe or do something (using reason or other methods) • To convince: to bring someone to embrace a belief or resolution by supplying sufficiently strong reasons • To manipulate: to control someone's beliefs and actions for a specific purpose

Persuading, convincing, manipulating

• • • • • • • • • •

Appealing to senses (smell, touch, sight) Suggesting lifestyles (family, youth, energy) Identification (celebrities, models) Creating and addressing fears Subliminal messages Imagination Product placement Repetition, frequency (recognition effect) Misleading comparison (30% off) Suggestive language (evocative, emotional, weasel words)

Methods of persuasion/manipulation in advertisement

• http://www.youtube.com/watch? v=RmEI3_NhZj4&feature=youtu.be

Supermarket psychology

Unbiased public service of investigation and factual reporting: • Advertising value • Customer taste and expectation • Entertainment value • Legal and cultural restrictions • Vested interest groups • Topic selection

Media

• Ask who owns a media outlet • How independent is it? • Who is it addressed to? (how educated, demanding, fairminded, interested) • Which presuppositions does it make? • How balanced is the view? • What is not said/reported on?

Questions to ask

• Read active: engage with the argument, find criticism, analyze • Try to understand the structure of the arguments • Read critical: ask about words used, framing • See what is not there! • Diversify sources

Further advice

Fallacies

Week 6 meeting 2

• Fallacies of inconsistency: contradicting or self-defeating claims • Fallacies with irrelevant premises: appealing to extraneous information • Fallacies with inacceptable/insufficient premises: assuming something without good reason

Three types of fallacies (Vaughn/Lau)

“I don’t speak a word of English.” “I always lie”

Inconsistency/Selfcontracition

• Genetic fallacy: Arguing that a claim is true or false solely because of its origin • Composition/Division: Arguing that what is true of the parts must be true of the whole or vice versa • Ad hominem (appeal to person): rejecting a claim by criticizing the person who makes it rather than the claim itself

Fallacies with irrelevant premises (Vaughn Ch.5)

“A supermarket chain wanted to buy up my block. They offered each party 1 Million $ for their flats. One of our neighbors declined and the deal fell through... At least now I know that my flat is worth a million or more.”

Example: fallacy of division

Bill: "I believe that abortion is morally wrong." Dave: "Of course you would say that, you're a priest."

Ad Hominem

“Arthur Conan Doyle (Author of Sherlock Holmes) probably had a drinking problem. His father was an alcoholic.”

Genetic fallacy

• Equivocation: the use of words in two different senses in an argument • Appeal to popularity (ad populum): arguing that claim must be true/false merely because a substantial number of people believe so • Appeal to tradition: arguing that a claim must be true just because it’s part of a tradition

Fallacies with irrelevant premises (2) (Vaughn Ch.5)

“I love you, all the world loves a lover, you are all the world to me, so you love me too”

Equivocation

There is a long tradition that arctic Inuit have hunted Seals. It is therefore not reasonable to interfere.

Appeal to tradition

There is no reason to pass an affirmative action policy to make people more equal. We are all naturally so different that people will never be equal.

Equivocation

• Appeal to ignorance: arguing that a lack of evidence proves something • Appeal to emotion: the use of emotions as a premises in an argument • Red herring: the deliberate raising of an irrelevant issue during an argument • Straw man: the distorting, weakening, or oversimplifying of someone’s position so it can be more easily attacked or refuted

Fallacies with irrelevant premises (3) (Vaughn Ch.5)

A: is making an argument that eating red meat is bad for your health B: supports the argument by saying that eating meat implies cruelty to animals

Red herring

“ Bigfoot does not exist. There simply has been not a single conclusive prove of his existence.”

Appeal to ignorance

“After Will said that we should put more money into health and education, Warren responded by saying that he was surprised that Will hates our country so much that he wants to leave it defenseless by cutting military spending.”

Straw man

Saying under tears: “I so much hoped and expected to get an A in this exam. You should give me an A”

Appeal to emotion/ ad misericordiam/wishful thinking

• Begging the question: the attempt to establish the conclusion of an argument by using that conclusion as a premise • False dilemma: incorrectly asserting that only two alternatives exist • Slippery slope: arguing without good reasons, that taking a particular step will inevitably lead to a further, undesirable step or steps

Fallacies with unacceptable premises (1) Vaughn (Ch. 5)

“You are either with us or you are against us” G. W. Bush

False dilemma

“If you allow using the pill after, you are on a road to allowing abortion at any stage of pregnancy, and why not legalize killing of infants and murder in general!?”

Slippery slope

“Where they burn books they will ultimately burn people also” Heinrich Heine

Is slippery slope necessarily a fallacy?

Interviewer: "Your resume looks impressive but I need another reference." Bill: "Jill can give me a good reference." Interviewer: "Good. But how do I know that Jill is trustworthy?" Bill: "Certainly. I can vouch for her."

Begging the question

• Hasty generalization: the drawing of a conclusion about a group based on an inadequate sample of the group • Faulty analogy: an argument in which the thing being compared are not sufficiently similar in relevant ways

Fallacies with unacceptable premises (2) Vaughn (Ch. 5)

“ Bill Gates, Mark Zuckerberg, and Steve Jobs dropped out of university and became very successful. I can afford to drop out too.”

Hasty generalization

No one objects to a physician looking up a difficult case in medical books during a medical examination. Why, then, shouldn't students taking a difficult examination be permitted to use their textbooks?

False analogy/ equivocation

1. Make sure you understand the argument 2. Identify conclusion (claim) 3. Identify premises 4. Fill in gaps and delete irrelevant parts 5. Determine if it is deductive or inductive 6. Evaluate it’s validity (or strength) 7. Evaluate it’s soundness (or cogency) 6/7a. Point out any fallacies 8. Draw a diagram or the argument’s structure 9. Comment on the argument and engage with it

Steps in analyzing arguments (slightly adapted)

Critical Thinking and Reasoning

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