Introduction to Fallacies February 10 th 3 1

Introduction to Fallacies February 10 th

3. 1 Fallacies The term ‘fallacy’ refers to a kind of reasoning failure involving invalid reasoning (in a formal fallacy) or otherwise faulty argumentation. Fallacies are generally the products of either a mistake in reasoning or the intentional creation of an illusion.

3. 1 Fallacies Formal fallacies are illicit moves in deductive arguments that make them invalid They can be identified by merely examining the form or structure of an argument. Remember, an example of an argument form is: All a are b. All c are b. All a are c. Where a, b, and c stand for terms.

Affirming the Consequent A formal fallacy. P 1: If A, then B P 2: B C: Therefore, A This is an invalid deductive argument.

Denying the Antecedent A formal fallacy P 1: If A, then B. P 2: Not A (A is not the case). C: Therefore, not B (B is not the case). This is an invalid deductive argument.

3. 1 Informal Fallacies Valid arguments can be informally fallacious Informal fallacies can be detected only by examining the content of the argument. Consider this example: The Brooklyn Bridge is made of atoms. Atoms are invisible. Therefore, the Brooklyn Bridge is invisible.

Informal Fallacy Subtype: Fallacies of Relevance Many informal fallacies can be categorized as ‘fallacies of relevance’ – argument strategies which rely on premises that are unrelated to the conclusion, or related to but not supportive of the conclusion. ◦ Some examples: ad hominem, argument from ignorance, and ignoratio elenchi (‘irrelevant conclusion’)

Logical Relevance vs. Psychological Relevance There is a big difference between what logically follows from a set of premises, and what seems to follow on a knee-jerk psychological level. . . In fallacies of relevance, often the conclusion seems emotionally relevant without being logically relevant. ◦ Halo effect

Identifying (and Avoiding) Generic “Fallacies of Relevance” • When trying to decide whether the reasons given in an argument are relevant or irrelevant, first find the actual conclusion of the argument. What question is at issue? • Premises are relevant or irrelevant only relative to a particular conclusion.

Identifying (and Avoiding) Generic “Fallacies of Relevance” In examining premises, ask yourself: • Would the truth of this premise make the conclusion more likely? • Would the falsity of this premise make the conclusion less likely? • If yes to these questions, then the premise is relevant. • If no, then the premise is irrelevant.

Types of Fallacies of Relevance Fallacies of relevance include two clusters of fallacies that have particular properties in common ◦ Appeals to emotion ◦ Genetic fallacies

Types of Fallacies of Relevance Let’s start with appeals to emotion…

3. 2 Specific Fallacies of Relevance Appeal to Force: ◦ This always involves a threat by the arguer to the physical or psychological well-being of the listener or reader, whether an individual or a group of people. ◦ You accept a conclusion out of fear or coercion. ◦ “If anyone in this room decides they support free contraceptive access, we’ll tell everyone right away what a giant slut they are. ”

3. 2 Specific Fallacies of Relevance Appeal to Pity: ◦ The arguer attempts to support a conclusion by evoking pity from the reader or listener, whether directed toward the arguer or toward some third party. ◦ “If the jury concludes that I am guilty, my children will have no one left to take care of them. ”

Genetic Fallacies Genetic fallacies attack conclusions based on properties related to the source of the conclusion.

AD HOMINEM scheme Assume some person X has argued for conclusion Y. ARGUMENT: Person X has argued that Y. Person X has characteristic C. Therefore, Y is false. OR: ARGUMENT: Person X has argued that Y. Person X has characteristic C. Therefore, we should reject X’s argument for Y.

Argument: P 1: Person X has argued that Y. P 2: Person X has characteristic C. Conclusion: Therefore, we should reject X’s argument for Y. There’s an implied premise here. Without it, the leap from the premise to the conclusion doesn’t make any sense. Implied premise: The fact that X has characteristic C is relevant grounds for rejecting X’s argument in favor of Y.

Argument: P 1: Person X has argued that Y. P 2: Person X has characteristic C. P 3: (implied) The fact that X has C is relevant grounds for rejecting X’s argument for Y. Conclusion: Therefore, we should reject X’s argument for Y. The argument is fallacious when this implied premise is false.

3. 2 Types of ad hominem abusive ◦ In this type of ad hominem, the subject dismisses the conclusion of an argument based on a supposed negative character trait of the person who put it forward.

AD HOMINEM ABUSIVE Example: P 1: Bill argues that anyone who can spare to give to charity is obligated to do so. P 2: Bill is forty years old and he still can’t parallel park. C: Therefore, Bill is wrong. (this is fallacious. )

AD HOMINEM ABUSIVE A trickier example: P 1: Bill argues that there is no such thing as continental drift. P 2: Bill has zero training in geology. P 3: Therefore, Bill is wrong that there is no such thing as continental drift.

IMPORTANT!!!! The fact that Bill lacks training in geology does not necessitate that his argument leads to the wrong conclusion. It’s not as if his limited knowledge of the subject can change the fact of the matter one way or another. However, his lack of expertise may give you a reason to be skeptical of his premises.

3. 2 Types of ad hominem circumstantial ◦ In the ad hominem circumstantial, the respondent attempts to discredit the opponent’s argument by alluding to the opponent’s circumstances. ◦ The respondent hopes to show that the opponent is predisposed to argue the way he or she does and should therefore not be taken seriously.

3. 2 Types of ad hominem circumstantial Form: P 1) X argues in favor of S. P 2) X stands to benefit if S were accepted. C) Reject X’s argument or claim for S.

3. 2 Types of ad hominem tu quoque In the tu quoque (“you too”) fallacy, the conclusion is attacked based on the claim that the author of the argument is a hypocrite or arguing in bad faith.

3. 2 Types of ad hominem tu quoque Form: P 1) X argues in favor of S. P 2) X acts in a way inconsistent with S. C: Reject X’s argument or claim for S.

3. 2 Types of ad hominem Watch out! Be wary of inverse ad hominems. The fact that some person has a positive characteristic does not guarantee that they have a good argument!

3. 2 Types of ad hominem Watch out! Be wary of inverse ad hominems. The fact that some person has a positive characteristic does not guarantee that they have a good argument! The fallacious appeal to unqualified authority (next lecture) is similar to an inverse ad hominem.

Other Fallacies of Relevance There a number of other fallacies that involve irrelevant premises, but which don’t fit into the categories of appeals to emotion or genetic fallacies.

3. 2 Fallacies of Relevance Accident Fallacy An accident fallacy or fallacy of accident is committed when a general rule gets applied to a specific case that it was not intended to cover. Example P 1) Cutting people with knives is a crime. P 2) Surgeons cut people with knives. C) Surgeons are criminals. As a rule of thumb, cutting people with knives is a crime – but we consider cases where people do so to save lives to be an obvious exception to the rule.

3. 2 Specific Fallacies of Relevance Appeal to Popularity / Bandwagon Appeal: ◦ The arguer attempts to support a conclusion by appealing to general agreement that it is the case. General form: A large group of people agrees that X. Therefore, X is true. Hidden premise: the consensus that X is the case is good evidence that X is, in fact, true. This argument is only fallacious when the hidden premise is false!

3. 2 Fallacies of Relevance Straw Man The straw man fallacy is committed when an arguer distorts an opponent’s argument for the purpose of attacking it more easily, demolishes the distorted argument, and then concludes that the opponent’s real argument has been demolished.

3. 2 Fallacies of Relevance Missing the Point This fallacy occurs when the premises of an argument support one particular conclusion, but then a different conclusion, often vaguely related to the correct conclusion, is drawn. When this is intentional, it is often referred to as a ‘red herring’ fallacy. - Note for identification: the ‘red herring’ applies when the switcharoo happens in response to another argument.

3. 2 Fallacies of Relevance Red Herring This fallacy is committed when the arguer diverts the attention of the reader or listener by changing the subject to a different but sometimes subtly related one. Either a conclusion is then drawn about this different issue or it is simply presumed that a conclusion has been established. This can be grouped with ‘missing the point’ in that the conclusion drawn is not the one that it should be being supported by the premises (here, because the subject is being changed for manipulative purposes)

Red Herring - Example “There is a good deal of talk these days about the need to eliminate pesticides from our fruits and vegetables. But many of these foods are essential to our health. Carrots are an excellent source of vitamin A, broccoli is rich in iron, and oranges and grapefruit have lots of vitamin C. ”

Have you seen any examples of these fallacies lately? In what context?