Classical Flaws Flashcards
To learn and identify classical flaws in reasonings.
It rains only Wednesday’s. Its Wednesday therefore its raining outside.
Bad Conditional Reasoning: What if we actually have to follow rules of conditional reasoning?
The flu is inversely correlated the amount of Vitamin C one has in their system. Out of 20 flu patients admitted to Westbank Hospital. 18 were moderately or severely low on Vitamin C. Therefore a lack of Vitamin C causes the flu.
Bad Casual Reasoning: What if one of the Omitted Options is the case?
Every member of Junes Book Club likes the novel Pride and Prejudice. Jane just joined the book club. Therefore Jane must like Pride and Prejudice.
Whole-to-Part & Part-to-Whole: What if wholes don’t necessarily equal parts?
On average video game prices have increased in price by 10% over the course of the past 5 years. This is not true. Knack 2 is 45% cheaper than 5 years ago; Spiderman is 20% cheaper; The Last of Us 15%.
Overgeneralization: What if we can’t generalize from this one thing to a bunch of other things?
Paul conducted a survey asking 50 college students what their IQ is. 3/4 of college students responded that their IQ is above average. Therefore most college students have above average IQ.
Survey Problem: 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?
In a recent study of college students, Class A (Spanish Class) and Class B (French Class), were required to make telemarketer calls. Class A closed more deals on average than Class B. It follows that learning Spanish improves ones telemarketing skills in some capacity.
False Start: What if the two groups were different in a key respect?
Despite our best efforts, we have not been able uncover a fossil larger than Titanosaur. In fact, no scientist has managed to prove the existence of any creature larger it. It follows that there is no prehistoric creature larger than the Titanosaur.
Possibility != Certainty: What if lack of evidence != evidence of lacking? What if proof of evidence != evidence of proof?
Walking 10,000 steps a day lowers the risk of heart attacks. Sophia knows that walking 10,000 steps a day is beneficial for her health. So, Sophia must know that walking 10,000 steps lowers her risk of a heart attack.
Implication: What if the person in question isn’t aware of what their belief implies?
John does not eat seafood, so he will not eat the seafood platter. Therefore John must eat the meat platter instead.
False Dichotomy: What if there are more than just two options?
Rebecca: We need to change our school’s hours for students. It is unreasonable to keep students at school for 8 hours with only one long break throughout the day.
Alice: So what you are saying is that we should let the kids just leave class whenever they want to. That’s going to lead to a lot of chaos.
Straw Man: What if they said has nothing to do with the claim they’re pretending to respond to?
Marie’s hair stylist said she would look good with bangs. However, hair stylists are always trying to convince people to cut their hair to make more money. So, Marie must not look good with bangs
Ad Hominem: What if this person’s character/motivation doesn’t affect the truth?
Talking to babies is useless. One might think that talking to babies might help develop language skills early on. But since its futile to talk to babies, its not worth doing.
Circular Reasoning: What if we can’t use the conclusion as evidence for itself?
Many workers at Factory A have reported that working conditions are poor and that the hours are long. But this claim is false. Factory A is totally in working condition and an hour is only 60 minutes.
Equivocation: What if we shouldn’t let words change in meaning?
Computer Expert Brian says that the biggest security risk of large organizations is un-secure passwords. Since Oldberry Inn is a large organization, therefore it must be true that their biggest security risk is un-secure passwords.
Appeal Fallacies: What if this opinion doesn’t equal evidence of fact?
Sanchez: The lot that the new park is planning to be built on is an ancient Native Burial site. As a result of the Native American Land Protection Act of 1887, all construction on native land is strictly forbidden.
Leslie: I agree Native Burial sites are said to be haunted so we should not build on the land since we dont want our kids to get scared.
Irrelevant: What if the premises and the conclusion have nothing to do with one another?
Yesterday I weighed 99lbs and I ate a 1 pound burrito. Therefore I was 1% burrito. Today I ate a two pound burrito, so today I must be 2% burrito.
Percentages != Numbers
