Common Flaws Flashcards
All dogs love to play with balls. Rover is a dog. Therefore, Rover loves to play with frisbees.
Dangling Variables (False Analogy)
New words that appear in the conclusion, and the author pretends that they are the same or has similar implications as something mentioned in the premises.
What if those two are not necessarily the same? What if X ≠ Y?
Kai likes to play basketball. Everyone who likes to play basketball is cool. Therefore, Kai has a girlfriend.
Dangling Conditional Variables (Missing Link)
A new concept that appeared in the conclusion but not in the premise. (A must arrow that appeared in the conclusion but not in the premises.)
What if you can’t add the ‘→X’ at the end of the chain?
Molly likes to eat chicken. Chickens are about to go extinct. Therefore, it is immoral for Molly to keep eating chicken.
Unsupported Value Judgment
Passing value judgments without defining them. (A type of dangling variables)
What if X is not [value judgment]?
[good, immoral, great, right, imprudent]
Molly is a better pet than TuoTuo because she is smarter, stronger, and more obedient.
Unmentioned Downsides
When the author only mention the upsides without mentioning the potential down sides.
What if the argument’s preferred option has some major downsides?
Working at internet companies could make one rich. Therefore, everyone should work in internet companies.
Assumed Universal Goals
When the author assumes that everyone has the same goal.
What if they don’t want to [assumed universal goal]?
When I walked in the room and saw the ransacked garbage bin, Molly was next to it. So Molly ransacked the bin.
Bad Causal Reasoning (Assumed Cause and Effect)
When there is a proposed cause and effect.
Omitted Options:
1. Independent: what if there’s no relationship at all?
2. Backwards: what if the causal relationship is actually backwards?
3. Other factors: what if some other factors caused one or noth?
If I’m hungry, then I will get angry. Therefore, when I’m angry, I’m also hungry.
or
Therefore, when I’m not hungry, I’m also not angry.
Bad Conditional Reasoning
When the rules of conditional reasoning are not being followed.
What if you can’t make those inferences from the conditional relationships in the premise?
The piece of pie in my hand is triangular, so the whole pie is triangular.
The whole pie is round, so the piece in my hand is round.
Parts ≠ Wholes (And Vice Versa)
When is the part/whole is claimed to have the same property as the whole/part.
What if parts don’t necessarily = wholes? (and vice versa)
Bob is from Greece, and Bob is a despicable person. Therefore, all people in Greece are despicable.
Overgeneralization (Parts ≠ All Parts)
When the property of a part is claimed to be the property of all parts (in that category or on that spectrum).
What if we can’t generalize from this one thing to all the other things?
A survey asked dog owners whether they like cats or not. 100% of the respondents likes cats. So all dog owners like cats.
Survey Problems
When the author makes a claim based on the result of surveys.
What if the survey is shit and is therefore untrustworthy?
A study compared groups of students with 3.1 GPA with those who have 4.0 GPA. They found that the 3.1 group eats less vegetables. Therefore, students who like to eat vegetables get higher grades.
Overlooked Differences Between Groups
When the author concludes that the differences in results from comparing two groups is solely due to the one key difference a study is focusing on.
What if there are other overlooked variables between the two groups that could have caused the difference in the results?
There’s no evidence that Molly ransacked the bin, so Molly did not do it.
There is some evidence that Tuotuo made this poop, so it must be TuoTuo who made this poop.
Possibility ≠ Certainty
When the author claims that there is no evidence for something being true, so it cannot be true.
When the author claims that there is some evidence for something being true, so it must be true.
What if no evidence for being true ≠ cannot be true?
What if some evidence for being true ≠ must be true?
Molly is a good dog. Everyone in the city likes good dogs. So if one were to ask someone on the city street, everyone would say they like Molly.
Truth ≠ Well-known Truth
When the author claims that something true is known by everyone to be true.
What if people don’t know that it is true?
Molly knows she will be going out. All dogs who go out have to wash their feet after they return. So Molly knows she has to wash her feet after she gets back.
Assuming Someone Believes the Implications of Their Beliefs
When the author provides a fact regarding the implication of someone’s belief, and claim that the person also believes in the implication.
What if they are not aware of the implication of their belief?
What if they are not logical thinkers?
Compared with yesterday, baby’s mood is not better. So it must be worse today.
I don’t like to eat durian, so I must eat pineapple.
False Dichotomy/False Dilemma
When the author limits the option/sections on a spectrum to 2 when there are more.
What if not more ≠ less?
What if not up ≠ down?
What if there are other options?
