Philosophy Intro to Logic: Chapter 4 Informal Fallacies

misleading precision

-a claim that appears to be statistically significant, but is not -ex: Our cookies contain 30% less fat, so you should start eating them of you want to lose weight.

post hoc fallacy

-a fallacy involving ashort-term or long-term pattern that is noticed after the fact -ex: Researchers have discovered that, for over 30 years, there has been a definite pattern connecting the party affiliation of the U.S. president and specific drink sales. During the years when a Democrat was president, Morphiacola topped all soft drink sales. When a Republican was president, Opiacola was number one in sales. If you are an investor, we advise you to put your money on the spot drink based on who is in the White House.

false dilemma

-a fallacy that occurs when 2 choices are asserted, each leading to an unwanted result, but there is a failure to acknowledge that other possibilities exist -ex: Either we give up some traditional basic freedoms or we lose the war on terror.

emphasis

-a fallacy that occurs when attention is purposely (or accidentally) diverted from the issue at hand -ex: Mary: Ann, you will wash the car this afternoon. Ann: I will? Mary: I'm glad you agree.

false dichotomy

-a fallacy that occurs when it is assumed that only 2 choices are possible, when in fact others exist -ex: Either you agree with me or you are an idiot.

red herring

-a fallacy that occurs when someone completely ignores an opponent's position and changes the subject, diverting the discussion in a new direction -ex: Many people criticize TV as turning America into an illiterate society. How can we criticize the very medium that is the envy of countries all over the world? The entertainment quality and variety of TV programs today are greater than even before, not to mention the enormous number of cable options available to members of the viewing audience.

straw man

-a fallacy that occurs when someone's written or spoken words are taken out of context -it purposely distorts the original argument to create a new, weak argument that can be easily refuted -ex: a person running for office might say: -I oppose the law that requires teaching intelligent design as an alternative to evolutionary theory in public school biology classes. Evolution is an established scientific theory and deserves to be taught in science class. Intelligent design is not a scientific theory, and should not be taught in a science class. an opponent might criticize them this way: -She is against the new law that mandates teaching intelligent design alongside the theory of evolution. It should be obvious to anyone that she really wants to eliminate religious beliefs. She wants us to destroy one of the basic principles of the Constitution of the U.S.

coincidence

-a fallacy that results from the accidental or chance connection between 2 events -ex: I can prove that some dreams let us see into the future. Last week, I dreamed that my cousin Charlie was in a car wreck. Just now, I got a phone call from my cousin Charlie's wife saying tat he is the hospital because he was in a car accident.

hasty generalization

-a generalization created on the basis of a few instances -ex: I saw a fraternity guy act rudely to a fast-food employee in the food court at lunch today. Probably most fraternity and sorority members are rude and arrogant.

complex question

-a single question that actually contains multiple, hidden parts -ex: Do you still cheat on your taxes?

appeal to pity

-a specific kind of emotional plea that relies solely on a sense of pity for support -ex: Your honor, before you sentence my client for the murder of his parents, I ask you to consider his situation. He is an orphan. Perhaps you can give him the lightest punishment possible.

appeal to force

-a threat of harmful consequences (physical and otherwise) used to force acceptance of a course of action that would otherwise be unacceptable -ex: If the workers of this company do not agree to a 25% cut in salary, then the company may have to shut its doors. Therefore, the workers of this company must agree to a 25% cut in salary.

tu quoque

-a variety of the ad hominem fallacy in which one person attempts to avoid the issue at hand by claiming the other person is a hypocrite -ex: You have been lecturing me about not joining a gang. But Dad, you were a gang member, and you never went to jail. So, I'll make my own decision about joining a gang

amphiboly

-ambiguity that arises when a poorly constructed statement muddles the intended meaning -ex: He was shot in the train in the back in the sleeping car.

appeal to ignorance

-an argument claiming that (1) a statement must be true because it has not been proven to be false or (2) a statement must be false because it has not been proven to be true -ex: UFOs exist because nobody has proven that they don't exist.

slippery slope

-an argument that attempts to make a final event the inevitable outcome of an initial act -ex: If you start smoking marijuana for pleasure, then you will need more and more to achieve the expected high. You will begin to rely on it whenever you feel depressed. Eventually you will experiment with more powerful drugs that act faster and longer. Of course, the amount of drug intake will have to increase to achieve the desired results. At this point, the addiction will take hold and will lead to a loss of ambition, a loss of self-esteem, the destruction of your health, and the dissolution of all social ties. Therefore, you should not start smoking marijuana.

appeal to unqualified authority

-an argument that relies on the opinions of people who have no expertise, training, or knowledge relevant to the issue at hand -ex: I'm Nick Panning, quarterback of Los Angels Seals. I've been eating Oaties for breakfast since I was a kid. Oaties provide nutrition and vitamins and helps build strong bones. Oaties taste great. You should get some for your kids today.

8 kinds of fallacies of relevance

-argument against the person -tu quoque -appeal to the people -appeal to pity -appeal to force -appeal to ignorance -missing the point -appeal to unqualified authority

begging the question

-argument that assumes as evidence in the premises the very thing that it attempts to prove in the conclusion -ex: Jane has the highest GPA among all the seniors in my school. There are 300 graduating seniors in my class. Therefore no senior has a higher GPA than she.

biased sample

-argument that uses a nonrepresentative sample as support for a statistical claim about an entire population -ex: A survey of 100 seniors at our university showed that 90% do not oppose a parking fee increase that will go into effect next year. Therefore, we can report that nearly all the students do not oppose a parking fee increase.

12 kinds of fallacies of unwarranted assumption

-begging the question -complex question -biased sample -accident -hasty generalization -misleading precision -false dichotomy -false dilemma -coincidence -post hoc fallacy -common cause fallacy -slippery slope

7 kinds of fallacies of ambiguity or diversion

-equivocation -amphiboly -composition -division -emphasis -straw man -red herring

common cause fallacy

-the assumption that one event causes another, when in fact both events are the result of a common cause -ex: She began making $100,000 the year after she graduated from college, and when she took an IQ test, she scored 20 points higher than when she was in high school. See, I told you: money makes people smarter.

appeal to the people

-the avoidance of objective evidence in favor of an emotional evidence in favor of an emotional response defeats the goal of a rational investigation of truth -the tactic appeals to people's desire to belong to a group -ex: Public school teachers are demanding a pay raise and threaten to strike if they don't get it. A prolonged strike will jeopardize our children's future. In addition, some economists predict that any substantial pay

equivocation

-the intentional or unintentional use of different meanings of words or phrases in an argument -ex: I was told that he is a big man on campus (BMOC). But look at him; he's no more than 5'7".

division

-the mistaken transfer of an attribute of an object as a whole to its individual parts -ex: He is huge, so he must have huge cells.

composition

-the mistaken transfer of an attribute of the individual parts of an object to the object as a whole -ex: All the cells in his body are tiny. Thus, he is tiny.

argument against the person

-when a claim is rejected or judged to be false based on alleged character flaws of the person making the claim -occurs whenever someone's statement or reasoning is attached by way of a stereotype, such as a racial, sexual, or religious stereotype -involves the use of the circumstances of a person's life to reject his claims -ex: Why should I believe what he says about the economy? He is not even a citizen.

accident

-when a generalization is inappropriately applied to the case at hand -ex: I can't believe that the police didn't give the driver of that ambulance any citations. That driver was speeding. The driver went through a red light. The ambulance swerved from lane to lane without using any turn signals.

missing the point

-when premises that seem to lead logically to one conclusion are used instead to support an unexpected conclusion -ex: Hey Mom, guess what I found out? If we buy a second car, the insurance will only be an additional $400 a year! Let's go get one before the insurance company changes the rate.

fallacies of ambiguity or diversion

a fallacy that occurs when the meanings of terms or phrases are changed (intentionally or unintentionally) within the argument, or when our attention is purposely (or accidentally) diverted from the issue at hand

fallacies of unwarranted assumption

arguments that assume the truth of some unproved or questionable claim

fallacies of relevance

fallacies that occur when irrelevant premises are offered in support of a conclusion