Introduction to Logical Fallacies Purpose: to briefly define some of the most common logical fallacies and apply that knowledge to a nonfiction reading.

fallacy Rationales for claims that might seem reasonable, but are actually unsound—and usually false. Unsound reasoning can stem from a multitude of problems in a person’s thought process (not a fact or belief).

Syllogism Premise: assertions, reasons, claims/ either true or untrue Conclusion: what logically follows the premises, natural conclusion to what was previously stated Definition of Syllogism: two assertions followed by a conclusion/ general conclusions drawn from specific facts All gorillas are mammals. Bobo is a gorilla. Therefore, Bobo is a mammal.

ad hominem An argument based on the failings of an adversary rather than on the merits of the case; a logical fallacy involving a personal attack. Argument is directed against the speaker rather than toward what the speaker is saying. Example: Bob is proposing to lower taxes, but Bob is a scoundrel; therefore, if we disapprove of lowering tax, then we disapprove their proposal as well.

false dilemma oversimplification that offers a limited number of options (usually two) when in fact more options are available. If the students are honest, then we don’t need an honor code. If the students are dishonest, then the honor code won’t work. Students are either honest of dishonest. Therefore, either we don’t need an honor code or an honor code won’t work. Therefore, it is a waste of time to institute an honor code.

Ambiguity The presence of two or more possible meanings in any passage Ambiguous words or statements lead to vagueness and confusion, and shape the basis for instances of unintentional humor. The intentional use of vague terms as a means of persuasion. Example: The passerby helps dog bite victim.

refutation Countering of anticipated arguments Negation of an argument, opinion, testimony, doctrine, or theory, through contradicting evidence (not with belief, values, or credibility).

Identifying Logical Fallacies Read the nonfiction article and identify as many flaws in logic that you can. Label those flaws as one of the three types: 1. The evidence has not been thorough; contradictory (counterarguments) evidence has been overlooked or ignored. 2. The evidence has not been accurate; false or unsubstantiated or misleading statements have been claimed as fact. 3. The conclusion has not clearly and uncontrovertibly come from the evidence; the relationship between evidence and conclusion has not been a firm one.

The Ways That People Tend to Think/Respond Reread the article and now label the ways that the author reflects the way people think (either himself or the audience) 1. tend to believe what they want to believe 2. Tend to project their own biases or experiences upon situations 3. tend to generalize from a specific event 4. Tend to get personally involved in the analysis of an issue and tend to let their feelings overcome a sense of objectivity 5. are not good listeners. They hear selectively and often only hear what they want to hear 6. are eager to rationalize 7. are often unable to distinguish what is relevant from what is irrelevant 8. are easily diverted from the specific issue at hand 9. are usually unwilling to explore thoroughly the ramifications of a topic– tend to oversimplify