Critical Thinking: Win Every Argument Every TimePresentation Transcript
Critical Thinking Win Every Argument Every Time
An argument consists of one or more premises and one conclusion.
A premise is a statement that is offered in support of the claim being made.
A conclusion is a statement that is the logical consequence of one or more premises.
For an argument to be valid its premises must support its conclusion. For an argument to be sound it must be valid and all premises must be true
A Valid Argument
All men are mortal, premise Socrates is a man. premise Therefore Socrates is mortal.
An Invalid Argument
Socrates is mortal, All men are mortal, Therefore Socrates is a man.
The argument is invalid although the conclusion is true
An Inductive Argument
Socrates is Greek,
Most Greeks eat fish,
Therefore, Socrates eats fish .
This is a strong or cogent inductive argument.
What Arguments are Not
Assertions : Prostitution is immoral.
Statements : Einstein said, “God does not play dice with the universe.”
Explanations : Because Caesar's army was outnumbered they retreated across the Rhine.
Opinions : ‘Norbit’ is a profound and deeply moving film.
Attacks the person instead of the argument.
Ex: “What she says about global warming is garbage, she never even graduated high school.”
Also, guilt by association.
Appeal to Authority
Making the claim that something is true based on the opinion of a supposed expert.
Ex: Michael Phelps may be an expert in swimming, but is he qualified to tell me what credit card I should have in my wallet?
Endorsements for Speedo are not fallacious!
Making the claim that if something is true in one or many situations it must be true for all situations.
Ex: One should never lie… A man approaches you with a smoking gun and asks “which way did my wife go?” Do you send him off in the right direction?
The converse of SG, Selective Observation, occurs when a an arguer uses the exception to the rule to support his conclusion.
Appeal to Consequence (Wishful thinking)
Making the claim that the consequences of some action whether positive or negative makes it true or false.
Ex: “I acknowledge that I have no argument for the existence of God. However, I have a great desire for God to exist and for there to be an afterlife. Therefore God exists.”
Appeal to Pity
An argument where an opponent tries to win support for his or her argument by exploiting emotions such as pity or guilt.
Appeal to Fear
An argument where an opponent attempts to create support for his idea by creating fear, prejudice, and uncertainty.
Ex: Any argument ending in “…we’ll all be killed in our beds.”
Appeal to Ignorance
This argument claims that lack of evidence automatically proves that something is untrue.
Ex: If ghosts actually did exist someone would have discovered undeniable proof of this by now. No such proof has been found, therefore, ghost do not exist.
Bandwagon (appeal to popularity)
The argument that something is true or right simply because a lot of people are doing it or believe it to be true.
Ex: Islam is believed by more people than any other religion, therefore it must be true.
Straw Man (fallacy of extension)
An argument based on the misrepresenting of an opponent’s position such that an easily knocked down target, or “straw man” is defeated rather than the actual issue or position.
Ex: “Senator Jones refuses to fund the attack submarine program. I don’t understand why he wants to leave our country defenseless like that.”
Begging the Question (circular reasoning)
An argument where the conclusion to be proved is assumed in one of the premises.
Ex: All intentional acts of killing human beings are morally wrong. The death penalty is an intentional act of killing a human being. Therefore, the death penalty is morally wrong.
An argument in which the claim is made that if one event happens a series of other undesirable events will follow.
Ex: the US should not get involved militarily with other countries. Once the government sends in a few troops it will then send in thousands to die.
Non Sequitur (it does not follow)
An argument where the conclusion is not supported by the premises.
Ex: Our nation will prevail because God is great!
Ex: Racism is wrong. Therefore, we need affirmative action.
Affirming the Consequent
This argument occurs when a hypothetical position with an antecedent and a consequent asserts that the truth of the consequent implies the truth of the antecedent.
Ex: If Bill Gates owns Fort Knox then he is rich. Bill Gates is rich, therefore he owns Fort Knox.
Inflation of Conflict
The argument that because scholars debate a certain point that they must know nothing, and their entire field is questionable or “in crisis.”
Ex: The Bible says the earth is 6,000 years old. Scientists disagree on how old the earth is. Therefore the earth is 6,000 years old.
False Dilemma (either/or fallacy)
This argument involves creating only two choices when in fact others exist.
“ Every nation, in every region, now has a decision to make. Either you are with us or you are with the terrorists” —George W. Bush
The fallacy of phrasing a question in such a way that it assumes something is true or false.
Ex: Do you support freedom and the right to bear arms?
The Gambler’s Fallacy
The belief that if deviations from expected are observed in repeated independent trials of some random process, these deviations are likely to be evened out over time.
Ex: The coin has landed on heads 9 times in a row. Therefore, the probability is that tails will be next. I’ll put my money on tails!
Confusing Correlation with Causation
An argument that claims because A and B are close to one another in time and space that A caused B.
Ex: Sexual assaults increase in direct correlation to the sale of ice cream. Therefore, ice cream should be banned to prevent these horrible crimes.
Argument by Selective Observation
Pointing to individual cases or data that seem to confirm a particular position while ignoring a significant portion of data that may contradict that position.
Ex: Doctor: “Why don’t people take care of themselves? My office is full of people who eat too much, drink too much, smoke, and don't get any exercise.”
This argument attempts to support its conclusion by making questionable or weak comparisons.
Ex: The universe is like a watch because it displays order and complexity. Therefore, the universe, like the watch, must have been made by an intelligent being.
Argument from Inconsistency
The fallacy of making inconsistent cause and effect relationships
Ex: The declining life expectancy in Russia is a failure of communism. But the high infant mortality rate in the United States is not a failure of capitalism.
An argument where the same word is used with two different meanings, or where definitions of words or phrases are so narrowly defined as to make a certain position more convincing.
Ex: “I did not have sexual relations with that woman.” —Bill Clinton
Genetic Fallacy (poisoning the well)
An argument where a conclusion is suggested based solely on someone or something’s origin.
Ex: “Yeah, the environment- a lists do claim that over- development can lead to all kinds of serious problems. But we all know about those granola-eating tree huggers!”
An ambiguous grammatical structure in a sentence that can be perceived as meaning two different things
Ex: Why go to another used car dealer to be cheated. Try us first!
Similar to amphibology, where meaning shifts based on context
Ex: I told Jack that I never want to see another Bruce Willis movie. As a result, he never shows me another one, he just keep showing me the same one, over and over…
It would be illegal to give away FREE BEER!
Two Wrongs Make a Right
An argument wherein one tries to undermine an opponent by pointing out that the same flaws present in himself, or where support is given for “eye for an eye, a tooth for a tooth” situation.
“ Those terrorists are justified in killing those people. After all their land was taken from them.”
Quoting Out of Context
Isolating what a person has said or written in such a way as to prove your argument.
“ To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest degree” --Charles Darwin, Origin of Species
Fallacy of Unrepresentative Sample
When a person draws a conclusion about a population that is based on a sample that is biased or prejudiced.
A well-documented scientific study shows that the consumption of eggs leads to higher cholesterol, but the study fails to mention that the participants were sedentary individuals in their 50’s who would have experienced heightened cholesterol regardless of diet.
Red Herring/The Chewbacca Defense
An argument where an opponent raises a side issue that may appear to be related to the issue at hand but is not.
Ex: It does not make sense. If Chewbacca lives on Endor, you must acquit!
The Fallacy of Division
An argument where characteristic of the whole are applied to its parts
Ex: John lives in a large building, therefore his apartment must be large.
Ex: Table salt is made of sodium and chlorine, therefore it must be OK to eat these chemicals.
The Fallacy of Regression or The Sports Illustrated Jinx
An argument where the arguer fails to take into account natural and inevitable fluctuations of things when ascribing causes.
A week after this appearance on the March SI cover Dennis Rodman missed four Lakers games and then took a leave of absence to address "personal matters." He filed for divorce on April 6. The Lakers released him from his contract on April 15.
The Normal Distribution Bell Curve
Identify which logical fallacies exemplify
the following arguments:
We should reduce sentences for child molesters. This will remove their incentive to silence their victims by killing them.
Animal experimentation reduces our respect for life and causes us to become more tolerant of violence and cruelty. The next thing you know they will allow experimentation on humans.
Bill: "I believe that abortion is morally wrong." Dave: "Of course you would say that, you're a priest."
Physicians cause 120,000 accidental deaths each year while handguns are only responsible for about 1,500 accidental deaths. Therefore doctors are more dangerous than guns.
Of course it rained today, I just washed my car!
If abortion becomes illegal women will just seek out dangerous back alley abortions.
It's okay for me to cheat on my taxes because everybody does it.
Really exciting novels are rare. But rare books are expensive. Therefore, really exciting novels are expensive.
The humanitarian work we do may well come out of our need to look good in front of our fellow man. So humanitarian work is basically egotistical!
Alcohol has many destructive effects on society yet remains legal. Therefore, we should legalize marijuana.
A recent study showed that violent offenders enjoyed watching violent movies and playing violent video games. Obviously these types of media make people violent.
Allowing same sex marriages will produce 10,000 marriages new marriages each year. The current divorce law punishes the primary wage earner. Look, Paul McCartney’s ex-wife got 50 million! How many people are going to be financially ruined when these marriages end in divorce?