Fallacies of Logic

Fallacies of Logic

By Michael Regalado

How would you like to win every argument?

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Learning how to construct and deconstruct and arguments will help you to gain the advantage in argument and debate.

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​What are fallacies of logic?

The next slide is linked to a website that explains the most commonly used, or misused, fallacies of logic.

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Take about ten minutes to read the definitions of each fallacy, and discuss in your table groups.

Next, we will practice identifying them, and look at some examples.

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​Fallacies of Logic

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Practice identifying common fallacies.

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You can help each other​, but the timer is on.

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​Fallacies of Logic

Multiple Choice

You misrepresented someone's argument to make it easier to attack.

• ad hominem

• slippery slope

• bandwagon

• false cause

• strawman

Multiple Choice

You said that if we allow A to happen, then Z will eventually happen too, therefore A should not happen.

• ad hominem

• slippery slope

• bandwagon

• false cause

• strawman

Multiple Choice

You attacked your opponent's character or personal traits in an attempt to undermine their argument.

• ad hominem

• slippery slope

• bandwagon

• false cause

• strawman

Multiple Choice

You appealed to popularity or the fact that many people do something as an attempted form of validation.

• ad hominem

• slippery slope

• bandwagon

• false cause

• strawman

Multiple Choice

You presumed that a real or perceived relationship between things means that one is the cause of the other.

• ad hominem

• slippery slope

• bandwagon

• false cause

• strawman

Multiple Choice

You presented two alternative states as the only possibilities, when in fact more possibilities exist.

• black or white

• anecdotal

• tu quoque

• personal incredulity

• composition/ division

Multiple Choice

You assumed that one part of something has to be applied to all, or other, parts of it; or that the whole must apply to its parts.

• black or white

• anecdotal

• tu quoque

• personal incredulity

• composition/ division

Multiple Choice

You avoided having to engage with criticism by turning it back on the accuser - you answered criticism with criticism.

• black or white

• anecdotal

• tu quoque

• personal incredulity

• composition/ division

Multiple Choice

You used a personal experience or an isolated example instead of a sound argument or compelling evidence.

• black or white

• anecdotal

• tu quoque

• personal incredulity

• composition/ division

Multiple Choice

Because you found something difficult to understand, or are unaware of how it works, you made out like it's probably not true.

• black or white

• anecdotal

• tu quoque

• personal incredulity

• composition/ division

Multiple Choice

You asked a question that had a presumption built into it so that it couldn't be answered without appearing guilty.

• loaded question

• Texas sharpshooter

• no true Scotsman

• burden of proof

• ambiguity

Multiple Choice

You said that the burden of proof lies not with the person making the claim, but with someone else to disprove.

• loaded question

• Texas sharpshooter

• no true Scotsman

• burden of proof

• ambiguity

Multiple Choice

You cherry-picked a data cluster to suit your argument, or found a pattern to fit a presumption.

• loaded question

• Texas sharpshooter

• no true Scotsman

• burden of proof

• ambiguity

Multiple Choice

You made what could be called an appeal to purity as a way to dismiss relevant criticisms or flaws of your argument.

• loaded question

• Texas sharpshooter

• no true Scotsman

• burden of proof

• ambiguity

Multiple Choice

You used a double meaning or ambiguity of language to mislead or misrepresent the truth.

• loaded question

• Texas sharpshooter

• no true Scotsman

• burden of proof

• ambiguity

Lets look at some examples.

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You can help each other​, but the timer is on.

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​Fallacies of Logic

Multiple Choice

When the judge asked the defendant why he hadn't paid his parking fines, he said that he shouldn't have to pay them because the sign said 'Fine for parking here' and so he naturally presumed that it would be fine to park there.

• strawman

• slippery slope

• ambiguity

• ad hominem

• anecdotal

Multiple Choice

After Sally presents an eloquent and compelling case for a more equitable taxation system, Sam asks the audience whether we should believe anything from a woman who isn't married, was once arrested, and smells a bit weird.

• strawman

• slippery slope

• ambiguity

• ad hominem

• anecdotal

Multiple Choice

Jason said that that was all cool and everything, but his grandfather smoked, like, 30 cigarettes a day and lived until 97 - so don't believe everything you read about meta analyses of methodologically sound studies showing proven causal relationships.

• strawman

• slippery slope

• ambiguity

• ad hominem

• anecdotal

Multiple Choice

After Will said that we should put more money into health and education, Warren responded by saying that he was surprised that Will hates our country so much that he wants to leave it defenseless by cutting military spending.

• strawman

• slippery slope

• ambiguity

• ad hominem

• anecdotal

Multiple Choice

If you allow the students to redo this test, they are going to want to redo every assignment for the rest of the year.

• strawman

• slippery slope

• ambiguity

• ad hominem

• anecdotal

Fallacy Assignment

​Your Task:

Spin the wheel to determine your assigned fallacy. Work with a partner to complete a slide explaining the fallacy.​

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