Chapter 6 – Fallacies Involving Credibility & Fallacies of ContextFallacies Involving Credibility
APPEAL TO AUTHORITY – using testimonial evidence for a proposition when the conditions for credibility are not satisfied or the use of such evidence is inappropriate.
This is usually called appeal to false authority, because not all appeals to authority are bad.
Think of any celebrity endorsement commercial-Michael Jordan telling you to wear Hanes underwear. MJ is awful cool, but he’s no Undergarment Scientist. From an advertising point of view this is good business, but not from the logical viewpoint. More sinister occurrences happen when someone who is an authority in a specific field urges a proposition concerning a related field. For example, you may have seen one of these commercials for the miracle weight loss pill-the endorser in the white lab coat with the stethoscope is not a doctor at all (in one case I saw someone in labeled ‘in residency’ which is apparently all the experience you need to give a medical recommendation for super-fat-destroying pills).
AD HOMINEM-using a negative trait of a speaker as evidence that their statement is false or their argument is weak.
Abusive – This is the easiest form of this fallacy to spot. It goes like this “You shouldn’t pick Susan to be on our basketball team because she’s a computer geek.” This fallacy aims at saying something distasteful about a person’s character. It is appropriate to attack someone’s character if it is on a relevant topic. If the prosecution’s star witness has a history of lying, that is very pertinent to the case.
Exception to the rule – it is OK to point out a negative personality trait as long as it is relevant. For instance, “Ms. Smiggles declares that she saw Mr. Rwowrth murder Mr. Gritspit. But many of her friends and coworkers have declared that Ms. Smiggles is a notoriously liar.”
Circumstantial-This form of Ad Hominem aims to hurt a person’s reputation through an association with something in that person’s context. For instance “You shouldn’t vote for Hilary Clinton because her husband’s brother is in jail.” You can attack someone for being in a bad circumstance that they helped cause. For example if someone is running for political office and it comes out that they were once part of a business that went bankrupt and that candidate had made decisions that contributed to the company’s demise, that would be important evidence to consider.
Tu Quoque-This means “you too”; it happens when one corrupt politician says to another corrupt politician “You’re corrupt” and the other one responds “that doesn’t matter, you are too!” That is to say, this is not a real excuse. If we found out that the Secretary of Defense had been using his government credit card to buy weekends in France, the Secretary of Defense will not help himself by saying, “but everyone’s doing it!”
Poisoning the Well-A particularly wicked kind of attack. For example if someone were to say “Of course you support universal health care, you’re a liberal!” The insinuation is that the accused is so dominated by their own ideology that they can’t think straight (see terrorists). The accused person can now say nothing that is not suspicious. Every reason that accused person would produce to support their claims will fall under the category, “Things Liberals Always Say.” So the accused person is left defenseless. The other way round it might look like this “Of course you support increased defense spending, you’re a conservative!” implying that being a conservative made it impossible to rationally consider defense spending. Surely there are people who are so completely wrapped in their own point of view that they cannot be rational, but this kind of attack is bad because it prevents any further debate.
Fallacies of Context
FALSE ALTERNATIVE (FALSE DELIMA) – excluding relevant possibilities without justification.
This fallacy usually presents two alternatives, one which the arguer wants you to pick and one which is undesirable. For example, “You can either volunteer for military service now, or you can be drafted later. You don’t want to wait to be drafted later as grunt, so you should volunteer now.” The problem is that those aren’t the only two options available to us. This fallacy is often committed by the demagogues who say things like “you’re either with us or you’re against us.” The move tries to scare people into joining the speaker for fear of becoming their enemy.
POST HOC-using the fact that one even preceded another as sufficient evidence for the conclusion that the first caused the second.
This will be the foundation of a lot of the superstitions. “I stepped under a ladder, and that made me have a bad day.” Stepping under the ladder only came before the rest of my day, but stepping under the ladder did not cause the rest of my day to sour. More sophisticated versions of this fallacy seek to reinterpret history such as “Since the American Civil War occurred before World War I, the Civil War is obviously the cause of World War I.”
Slipper Slope-This version of Post Hoc seeks to set up a chain of events to connect two unrelated propositions. Here’s an example “If you start listening to the Beatles, you’ll want to listen to other rock ‘n roll, then you’ll listen to Nirvana, then you’ll start smoking and drinking, and that will lead marijuana, which will in turn lead to coke, crack, meth, and steroids, and the only way to keep up you’re habit you’ll have to steal, and someone will shoot you. So, if you don’t want to be shot to death, don’t listen to the Beatles.”
HASTY GENERALIZATION-inferring a general proposition from an inadequate sample of particular cases.
Taking to few samples and then generalizing to broadly is what’s happening here. This fallacy is most often seen in arriving at stereotypes of people. For instance, “The perpetrators of the 9/11 massacre were Islamic, therefore all Islamic people are terrorists.”
COMPOSITION-inferring that a whole has a property merely because its parts have that property
For example, “This sparkplug is part of the car. It is very light. So, the whole car must be light.” This is a lot like Hasty Generalization. Here’s a more sinister example, “Ralph is Native-American and Ralph is an anarchist, so all Native-Americans must be anarchists.”
DIVISION-inferring that a part has a property merely because the whole has that property.
For instance, “This computer is heavy, so all of its parts must be heavy.” More sinisterly, “In the U.S., most people believe in God, so my buddy, Garth, must believe in God.”