The Classic Flaws

Bad Conditional Reasoning

• Occurs when the author reads the conditionals supplied in the premises incorrectly

• The author will either conclude something by reading the conditional premises backwards without negating, or conclude something by negating the conditional premises and reading it forwards

Bad Conditional Reasoning Loophole

What if we actually have to follow the rules of conditional reasoning?

Bad Causal Reasoning

• Occurs when the author sees two things are correlated and concludes that one of those two things is causing the other

• Correlation ≠ Causation

Bad Causal Reasoning Loophole

What if one of the omitted opinions is the case?

1. What if there’s no relationship here at all?

2. What if the causation is backwards?

3. What if a new factor caused one or both these things?

Whole to Part & Part to Whole

• Occurs when the author goes from premises about all the parts of something having a property to a conclusion about the whole having that property and vice versa

• *Think of the piece of pie example

Whole to Part & Part to Whole Loophole

What if wholes don’t necessarily equal parts?

Overgeneralization

• Occurs when the author talks about something having a property and concludes that a bunch of other things also have that property

• The premises are about something specific, and the conclusion overgeneralizes that property

• Overgeneralization is the part-to-part flaw

Overgeneralization Loophole

What if we can’t generalize from this one thing to a bunch of other things?

Survey Problems

• Occurs when there’s a survey, the author concludes things based on the survey, and there are all kinds of silent things wrong with the survey

• Common Survey Mistakes:

  • Biased sample

  • Biased questions

  • Other contradictory surveys

  • Survey liars

  • Small sample size

Survey Problems Loophole

What if the sample was biased, the questions were biased, there are other contradictory surveys, people lie on surveys, or the sample is too small?

False Starts

• Occurs when the authors/researchers assume that two groups are the same in all respects except the ones called out as part of the study

• There’s a study with two groups, the author/researcher assumes the two groups are the same in all respects except those pointed out as part of the study, concludes that the differences in the study results are due to the one key difference the study is focusing on

False Starts Loophole

What if the two groups were different in a key aspect?

Possibility ≠ Certainty

• Occurs when you can’t prove its true/false. Therefore, it cannot be true/false, OR

• Occurs when there is some evidence it’s true/false. Therefore, it must be true/false

• Two Patterns:

  • Lack of Evidence ≠ Evidence of Lacking

    • It’s not necessarily true, so it cannot be true 

  • Proof of Evidence ≠ Evidence of Proof 

    • It could be true, so it must be true

Possibility ≠ Certainty Loophole

What if lack of evidence ≠ evidence of lacking?

What if proof of evidence ≠ evidence of proof?

Implication

• Occurs when someone has a belief, the author mentions a factual implication of that belief, and the conclusion claims that that someone believes the implication of the belief

• Implication tells people what they believe—a tricky slope

Implication Loophole

What if the person in question isn’t aware of what their belief implies?

False Dichotomy

• Occurs when the author outlines two possible options, eliminates one of the options, and concludes the second option must be the case 

• Two Types of False Dichotomies:

  • Limiting a Spectrum:

    • Spectrum limiting authors pretend there are only two options, when there are really three: up, down, or unchanged 

  • Limiting Options:

    • Options limiting authors pretend there are only two options when there could be more

False Dichotomy Loophole

What if there are more than just two options?

Straw Man

• Occurs when the author “responds” to an opponent by “mishearing” what was said to them

• Person 2 will distort what Person 1 said to make Person 1’s point easier to take down

Straw Man Loophole

What if what they said has nothing to do with the claim they’re pretending to respond to?

Ad Hominem

• Occurs when someone makes a claim, the author attacks how that person is somehow awful/unintelligent/etc., and concludes the person’s claim must be false

• Ad Hominem is Latin for “to the person”

• This flaw attacks a person, not the actual claim

• Ad Hominem can also attack the proponent’s motivations 

  • A proponent’s bias for or against a position does not affect the truth or falsity of that position 

  • Premises about character and motivation only prove claims about character and motivation

Ad Hominem Loophole

What if this person’s character/motivation doesn’t affect the truth?

Circular Reasoning

• Occurs when the author concludes something, then supplies premises that assume the conclusion is already true

• This flaw assumes the conclusion is true before doing the work of proving it 

• When there is repetition between the premises and conclusion, they’re using circular reasoning

Circular Reasoning Loophole

What if we can’t use the conclusion as evidence for itself?

Equivocation

• Occurs when the author uses a word or idea, intending one of its possible meanings, and concludes something using the other possible meaning of the word or idea

• This flaw changes the meaning of a word throughout an argument

Equivocation Loophole

What if we shouldn’t let words change in meaning?

Appeal Fallacies

• Occurs when the author says that a person or group believes something, and concludes that thing must be true 

• This flaw is about turning someone’s opinion into fact

• Two Types of Appeal Fallacies:

  • Invalid Appeal to Authority:

    • Happens when the author uses a non-expert opinion to support their conclusion 

  • Invalid Appeal to Public Opinion:

    • Invalid because people are unreliable; a high percentage of random people believing anything has very little bearing on whether that thing is actually true 

Appeal Fallacies Loophole

What if the opinion doesn’t equal evidence of fact?

Irrelevant

• Occurs when the author supplies a few premises and concludes something unrelated to those premises

• Only choose irrelevant when you can’t detect a more specific, compelling classic flaw in the stimulus 

Irrelevant Loophole

What if the premises and the conclusion have nothing to do with one another?

Percentage ≠ Numbers

• Occurs when…

  • The author says “a % went up!” then concludes that the associated real number also went up, OR

  • The author says “a # went up!” then concludes that the associated percentage also went up 

• A rising percentage doesn’t necessarily imply a rising number and vice versa because there’s one big thing they’re purposefully not mentioning: group size