5/22/2011

20 Common Logical Fallacies

Is anyone else weary of politicians using simple rhetorical tricks to bamboozle credible/gullible citizens into believing night is day, black is white, and that whatever's wrong in the world is definitely someone else's fault?

If I ran the school system, all kids would get mandatory instruction in rhetoric, more commonly known as "the art of persuasion".  They would be required to learn both how to compose logical arguments, and how to recognize/expose logical fallacies in the arguments of others.  I believe that if U.S. citizens were to start out calling politicians for trying to bamboozle us with rhetorical "tricks", our lawmakers would be forced to assume a drastically more rational approach to governance.

Have drawn examples from real life/news to illustrate each fallacy.  Some of these examples are inevitably partisan.  To compensate, I've tried to pick examples from all points along the political spectrum, from extreme liberalism to extreme conservativism.   Please don't let your opinion of the issues distract you from the fact that each example demonstrates a flawed argument.  (How many of these have you fallen for?)

  1. Drawing conclusions from too little evidence.
    DEFINITION: Generalizing from incomplete information.
    EXAMPLE: If ________ is a Republican, he must believe in tax cuts.  (Failing to acknowledge that individual Republicans may hold different opinions than their party on some issues.)
  2. Overlooking alternatives. 
    DEFINITION: Saying that two items are causational (one causes the other), when in fact they merely correlate (tend to happen together; or, are both caused by the same external factor)EXAMPLE: Families that eat dinner together have students who do better in school.  (Family dinners don't cause intelligence - rather, the value system that promotes family dinners also promotes other values that positively impact school performance.)
  3. Ad absurdem.
    DEFINITION: Extending an argument to the point of absurdity.
    EXAMPLE: If we let gays marry, what's next - letting people marry their dogs?
  4. Ad hominem. 
    DEFINITION: Attacking a person rather than his/her qualifications. 
    EXAMPLE: What does Sarah Palin know about government?  She was a beauty queen! 
  5. Ad ignorantiam.
    DEFINITION: An appeal to ignorance.  Arguing that a claim is true just because it has not been shown to be false. 
    EXAMPLE: Standardized testing will improve the academic performance of students
  6. Ad misericordiam. 
    DEFINITION: An appeal to pity.  
    EXAMPLE: I was a prisoner of war; I deserve a chance to run the country that I've served so nobly.
  7. Ad populum. 
    DEFINITION: Appealing to the emotion or the common consensus of the crowd. 
    EXAMPLE: Lots of folks in the Iowa straw pole voted for Huckabee - he must be a serious candidate.
  8. Affirming the consequent. 
    DEFINITION: Basically, if cause = effect, then effect = cause. 
    EXAMPLE = When oil supplies are low, gas prices go up.  Gas prices are high, so oil supplies must be low.  (Doesn't acknowledge that there are other factors, besides supply, that impact oil prices.  Think about that the next time a politician argues that the key to lowering oil prices is releasing inventory from the Strategic Fuel Supply.)
  9. Begging the question/ circular argument. 
    DEFINITION = Implicitely using your conclusion as a premise
    EXAMPLE = I know intelligent design is true because the Bible says so.
  10. Complex question.  
    DEFINITION = Posing a question or issue in such a way that people cannot agree or disagree with you without commiting themselves to some other claim you wish to promote.
    EXAMPLE = Do you agree that the economy has gotten worse since the Democrats took office? (If you say no, you're admitting to a certain level of dimness; if you say yes, you're implying that you agree that Democrats were the cause.)
  11. Denying the antecedent. 
    DEFINITION = If p means q, then not-p means not-q
    EXAMPLE = When a country is under despotic rule, people revolt.  People in China are not currently staging revolutions; therefore, the country is not under despotic rule.
  12. False dilemma. 
    DEFINITION = A generic term for a questionable conclusion about cause and effect.
    EXAMPLE = If we cut government spending, Medicade will suffer.  (Doesn't acknowledge that government spending can be cut without touching Medicade.)
  13. Non sequitur.
    DEFINITION = A conclusion that is not a reasonable inference from the evidence.
    EXAMPLE = Democrats are pro-choice.  They hate Christians.
  14. Persuasive definition/loaded definition. 
    DEFINITION = Defining a term in a way that appears to be straightforward but that is in fact loaded/biased.
    EXAMPLE = The Tea Party is dedicated to the issues that matter to ordinary Americans.   (Who are these "ordinary Americans" they speak of?)
  15. Poisoning the well. 
    DEFINITION = Using loaded language to disparage an argument before even mentioning it
    EXAMPLE = Some liberal diehards still clinging to the 1960s will tell you that American needs to resume its isolationist stance towards the rest of the world.
  16. Post hoc, ergo protor hoc. 
    DEFINITION = Literally, "after this, therefore because of this" - arguing that because something happened after something else, the first thing must have caused the second. 
    EXAMPLE = The economy got worse after George Bush took office, so clearly it's his fault.
  17. Red herring. 
    DEFINITION = Introducing an irrelevant or secondary subject to divert attention from the main subject
    EXAMPLE = Obama wasn't born in the United States! And he's a muslim!
  18. Straw man. 
    DEFINITION = Characterizing an opposing view so that it is easy to refute.
    EXAMPLE = Do you want politicians telling you how you have to spend your money?
  19. Weasel word. 
    DEFINITION = Changing the meaning of a word in your argument so that your conclusion can be maintained, though its meaning may have shifted radically
    EXAMPLE = Torture is unethical!  But waterboarding is okay because it's not technically "torture" 

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