Faulty Reasoning

What is a fallacy?

• “fallacy is a generic term that indicates an error or weakness in an argument or thought process.” (Ziegmuller and Kay)

• The source of a fallacy may be found in the data, the reasoning process, the language, or the strategic or psychological basis of the argument.

Common fallacies:

• Red Herring: introduces an irrelevant issue in order to divert attention from the subject under discussion.

• Example:– “The real problem is not eliminating

handguns; the real problem is that pawnshops that sell guns are controlled by the Mafia.”

More:

• Ad Hominem (mudslinging): substitutes an attack on the person for discussion of the real subject under discussion.

• Example:– “Tony is an awful musician and is not

sensitive enough to chair such an important committee.”

More:

• False dilemma (either-or): forces listeners to choose between two alternatives when more than two exist.

• Example:– “Either more people should start

volunteering their time to work for their community, or your taxes will increase.”

More:

• Bandwagon: assumes that because something is popular, it is therefore good, correct, or desirable.

• Example:– “Most people agree with me that we

spend too much time worrying about Medicare.”

More:

• Slippery slope: assumes that taking a first step will lead inevitably to a second step and so on down the slope to disaster.

• Example:– “Passing federal laws to control the

amount of violence on television is the first step in a process that will result in absolute government control of the media and total censorship over all forms of artistic expression.”

More:• Hasty generalization: A person who

reaches a conclusion from too little evidence or nonexistent evidence.

• Example:– “It’s clear that our schools can’t educate

children well, because my niece went to school for six years and she still can’t read at her grade level.”

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• Post Hoc, Ergo Propter Hoc (“After this, therefore because of this” or false cause): assume that because one event comes after another, the first event must necessarily be the cause of the second.

• Example:– “The decline of morals in this country is

caused by excessive government spending.”

Let’s test your knowledge!

• “I don’t see any reason to wear a helmet when I ride a bike. Everyone bikes without a helmet.”

• Answer-bandwagon fallacy• “It’s ridiculous to worry about

protecting America’s national parks against pollution and overuse when innocent people are being endangered by domestic terrorists.”

• Answer-red herring fallacy

More:

• “There can be no doubt that the Great Depression was caused by Herbert Hoover. He became President in March 1929, and the stock market crashed just seven months later.”

• Answer-Post Hoc, Ergo Propter Hoc or false cause.

More:

• “If we follow the school board to spend money remodeling the gymnasium, next they will want to build a new school and give all the teachers a huge raise. Taxes will soar so high that businesses will leave and then there will be no jobs for anyone in this town.”

• Answer-Slippery slope fallacy

More:

• “ I can’t support Representative Frey’s proposal for campaign finance reform. After all, he was kicked out of law school for cheating on an exam.”

• Answer-ad hominen fallacy.

More:

• “One nonsmoker, interviewed at a restaurant, said, “I can eat dinner just fine even though people around me are smoking.” Another, responding to a Los Angeles Times survey, said, “I don’t see what all the fuss is about. My wife has smoked for years and it has never bothered me.” We can see that secondhand smoke does not cause a problem for most nonsmokers.”

• Answer-hasty generalization.

More:

• “Our school must either increase tuition or cut back on library services for students.”

• Answer-False dilemma or either-or fallacy.

Conclusion:

• Use fallacies as a way to identify fault in other’s arguments as well as our own.

• By exposing fallacies in arguments it helps build strong sound reasoning.