Faulty Arguments,Logical Fallacies

and Poor Reasoning

Faulty Arguments• This PowerPoint contains some of the

common errors people make in reasoning.

• If you listen, you will hear many of these fallacies in everyday conversation.

• The “natural” cure and herbal medicine literature is rife with glaring examples of poor argumentation.

• Study these generic examples and you will be able to spot them in the assigned articles with ease.

Poor Logic

Emotional Appeal• This is an attempt to

sway the listener by getting him emotionally involved.

• Emotions shut down reason!

• Sick or scared people are especially vulnerable.

Ad Hominem/ Personal Attack• Arguments of this kind

focus on the character of the person advancing it; they seek to discredit positions by discrediting those who hold them.

• They attack the arguers rather than the arguments.

• Politicians are often subjected to ad hominem attacks

Bandwagon/ Ad Populum• The difference

between the two is that the bandwagon fallacy places an emphasis on current fads and trends, whereas the ad populum suggests that an idea must be true simply because it is widely held.

Appeal to Authority

• For example, an appeal to authority argument seeks to persuade by citing what someone else, a perceived authority, thinks on the subject, as if that resolves the question. The degree of support that such an appeal lends to a claim varies depending on the particular authority in question, the relevance of their expertise to the claim, and other factors, but in all cases is limited.

Appeal to Authority• An appeal to authority argument

seeks to persuade by citing what someone else, a perceived authority, thinks on the subject, as if that resolves the question.

• Celebrity endorsements sell products.

• Even worse, celebrity endorsements of political figures win votes. Yikes!

Faulty Statistics

• Misunderstanding or misusing statistics to shore up a weak argument.

• Example: “We must fund our schools better! Half our children are below average on their math tests!”

• People pull bogus statistics out of thin air to sound impressive.

Research by Exegesis• Research by exegesis is

using a book as an infallible reference source.

• Usually it refers to the supposedly infallible Bible, but not always.

• People cite Bible verses to convince people that being gay is wrong.

Either/Or & Slippery Slope

• Slippery slope arguments falsely assume that one thing must lead to another.

• They begin by suggesting that if we do one thing then that will lead to another, and before we know it we’ll be doing something that we don’t want to do.

• They conclude that we therefore shouldn’t do the first thing.

• The problem with these arguments is that it is possible to do the first thing that they mention without going on to do the other things; restraint is possible.

Slippery Slope Example

• “If you go out with that kind of guy, you will get pregnant and end up dropping out of college.”

• Either you stay in school or you won’t get a good job.

Red Herring• The red herring is as much a debate tactic as it is a

logical fallacy. • It is a fallacy of distraction, and is committed when a

listener attempts to divert an arguer from his argument by introducing another topic.

• This can be one of the most frustrating, and effective, fallacies to observe.

• The fallacy gets its name from fox hunting, specifically from the practice of using smoked herrings, which are red, to distract hounds from the scent of their quarry.

• Just as a hound may be prevented from catching a fox by distracting it with a red herring, so an arguer may be prevented from proving his point by distracting him with a tangential issue.

Red Herring Example

• “You may think that he cheated on the test, but look at the poor man! How would he feel if you made him take it again?”

• This red herring also includes an appeal to pity.

Straw Man

• The straw man fallacy occurs when a statement misrepresents or invents an opponent's view (sometimes even the opponent is invented) in order to easily discredit it.

• The straw man argument is intended to give the appearance of successfully refuting the original argument, thus creating the impression that it has refuted a position that someone actually holds.

• A straw man is constructed expressly for the purpose of knocking it down.

Straw Man Examples

(1) Trinitarianism holds that three equals one.

(2) Three does not equal one.

Therefore:

(3) Trinitarianism is false.• (Trinitarianism does not

actually say that 3 =1)

Can you find the straw man in this?:

• Republicans attack Democrats for spending too much tax money.”

Testimonial

• Personal statements and anecdotal stories are mistaken for scientific proof.

• Example: “I lost 100 pounds on Diet drink and you can too!”

Circular Reasoning/ Begging the Question• An argument is circular if

its conclusion is among its premises, if it assumes (either explicitly or not) what it is trying to prove. Such arguments are said to beg the question.

• “We’re all good Christians here…”

• (1) The Bible affirms that it is inerrant.

• (2) Whatever the Bible says is true.

• Therefore: • 3) The Bible is inerrant.

More Examples of Circular Reasoning• Typical examples of

circular arguments include rights or claims.

• I have a right to choose whether to have an abortion or not, therefore abortion should be allowed

• The unborn has a right to life, therefore abortion is immoral.

• Having a right to X is the same as other people having an obligation to allow you to have X, so each of these arguments begs the question, assuming exactly what it is trying to prove.

Non Sequiter

• Literally this means, “It does not follow”

• Ex. Giving up our nuclear arsenal in the 1980's weakened the United States' military.

• Giving up nuclear weaponry also weakened China in the 1990s.

• For this reason, it is wrong to try to outlaw pistols and rifles in the United States today

Equivocation1) Nothing is better than

eternal happiness.2) A ham sandwich is

better than nothing.Therefore:3)A ham sandwich is

better than eternal happiness.

(Nothing means different things.)

“I didn’t have sex with her” (She performed a sex act on me, but hey…)

False DilemmaThe bifurcation fallacy is committed when a

false dilemma is presented, i.e. when someone is asked to choose between two options when there is at least one other option available.

(1) Either a Creator brought the universe into

existence, or the universe came into existence out of nothing.

(2) The universe didn’t come into existence out of nothing (because nothing comes from nothing).

Therefore:(3) A Creator brought the universe into

existence.

False Dilemma Example

“Do I trust the word of a madman and forget the lessons of September the 11th, or take action to defend America? Given that choice, I will defend America every time.— Bush 9/3/04

Hasty Generalization:(Jumping to conclusions)

• Ex. "Susan failed Biology 101.

• Herman failed Biology 101.

• Jose failed Biology 101.

• I therefore conclude that most students who take Biology 101 will fail it."

Glittering Generalities

• Use attractive, but vague words that make speeches and other communications sound good, but in practice say nothing in particular.

• Example: We are fighting for truth and freedom!

Prejudice & Stereotypes

• Any statement that starts (or implies) with “All…” or “Most…” or implies

• Asian women are such poor drivers!• Men are dogs.

Faulty Analogy

• A faulty or weak analogy tries to relate two disparate things.

• An expert suggests that a watch and the universe are similar (both display order and complexity), and therefore infers from the fact that watches are the product of intelligent design that the universe must be a product of intelligent design too.

Dogmatism

• This is a tendency to express strongly held opinions in a way that suggests they should be accepted without question.

• “I believe that women should stay at home and raise the children or else our moral values in this country will go to hell!”

Post Hoc

• The Latin phrase post hoc ergo propter hoc means, literally, after this therefore because of this.

• The post hoc fallacy is committed when it is assumed that because one thing occurred after another, it must have occurred as a result of it.

• Mere temporal succession, however, does not entail causal succession.

• Just because one thing follows another does not mean that it was caused by it.

Post Hoc Example

• Nestle, the makers of the breakfast cereal Shredded Wheat, once ran an advertising campaign in which the key phrase was this: “People who eat Shredded Wheat tend to have healthy hearts.”

Another Post Hoc Example

• (1) Most people who are read the last rites die shortly afterwards.

Therefore: • (2) Priests are going

around killing people with magic words!

Tu Quoque(Two Wrongs Don’t Make a Right)

• The tu quoque fallacy is committed when it is assumed that because someone else has done a thing there is nothing wrong with doing it.

• This fallacy is classically committed by children who, when scolded, respond with, “So and so did it too!” with the implied conclusion that there is nothing wrong with doing whatever it is that they have done.

• Do you remember the A&F tee shirt that read, “Two Wongs don’t make a white” ?

Tu Quoque Example

(1) The Romans kept slaves.

Therefore: (2) We can keep

slaves too.Ex. “But Susie did

it….., why can’t I?”

Jargon• Technical and hard to

understand language is often used to persuade unsuspecting people that a product is scientifically proven to be effective.

• A good rule of thumb is that if you can’t understand it and it was written for the public, then you aren’t supposed to understand it! Someone is counting on you NOT understanding anything.

Occam’s Razor

• William of Ockham was a medieval (ca 1300) English philosopher

• He proposed that if 2 theories explain the same thing, always choose the simplest.

• We know this today as K.I.S.S. (keep it simple, stupid)