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Flaw Type
Flaw type
flaw type
100

What is an exclusivity flaw?

An exclusivity flaw arises when an argument presents two or more options as if they are the only possible choices, and implies that if one is true, the others must be false

"Either/Or" Fallacy: The argument uses "either/or" language, suggesting that only one of two options is possible. 

  • Ignoring Combinations: The argument fails to consider the possibility of combining multiple options or finding a solution that goes beyond the presented alternatives. 

Shows up like this:

  • "Only" Language: The argument uses words like "only," "sole," or "must" to suggest that one option is the exclusive solution

Examples: 

  • "We must either cut taxes or increase government spending. We can't do both." (This ignores the possibility of finding a middle ground or balancing the two). 
  • "To improve the economy, we must either raise interest rates or lower the exchange rate. We can't do both.".
100

What is a Causal flaw?

(also known as a correlation-causation flaw) occurs when an argument incorrectly assumes that because two things are correlated, one causes the other

Look for language that suggests a cause-and-effect relationship (e.g., "causes," "leads to," "results in"). 

  • Consider if there could be other explanations for the correlation. 
  • Ask yourself if the argument is overstating the relationship between two things. 

Example: 

Every time the price of coffee goes up, sales of tea increase. Therefore, higher coffee prices cause people to drink more tea."


200

What is a sampling flaw

Occurs when an argument draws a broad conclusion from a non-representative or biased sample, making the evidence insufficient to support the conclusion

  • Look for polls, surveys, or studies: These are often the basis for arguments that could be flawed by sampling. 
  • Identify a shift from specific evidence to a general conclusion: The evidence might be about a small group, but the conclusion is about a much larger group. 
  • Consider whether the sample is representative: Does it accurately reflect the diversity of the population being studied? 

Examples: 

Example 1: "I saw a group of teenagers wearing band t-shirts at the concert, so all teenagers must be into rock music." (The sample of teenagers at a rock concert is not representative of all teenagers). 

  • Example 2: "I surveyed my friends and they all said they prefer coffee over tea, so everyone must prefer coffee." (The sample of friends is not representative of the general population
200

What is a Attacking the Person/Ad Hominem flaw?

occurs when an argument discredits an opponent's position by attacking their character, motives, or personal traits, rather than addressing the argument itself

Look for arguments that: 

  • Focus on the speaker's character or background rather than the argument's content. 
  • Use insults, accusations, or personal attacks to undermine an opponent's position. 
  • Claim that someone's argument is invalid because of their personal flaws or biases. 

Example: 

"My doctor tells me it's bad for your lungs to smoke cigarettes, but I know he's lying. I saw him furtively smoking a cigarette the other day

300

What is a Temporal flaw?

occurs when an argument incorrectly assumes that a correlation or trend observed at one time will hold true at another time, or that what was true in the past will continue to be true in the present or future

Look for arguments that: 

  • Compare past events to present or future events. 
  • Assume that what was true in the past will continue to be true in the future.
  • Fail to consider that circumstances might have changed, or that a trend observed in the past might not continue. 

For example, if an argument assumes that ice cream sales will increase this summer because they increased last summer, it fails to consider that what may have been true in the past does not have to be true in the future.

300

What is a Percentage vs. Amount flaw?

occurs when an argument incorrectly assumes that a percentage change in a quantity implies a similar change in the absolute amount or vice versa

Look for arguments that: 

  • Draw conclusions about absolute amounts based solely on percentages. 
  • Draw conclusions about percentages based solely on absolute amounts. 
  • Fail to consider the size of the base or total when discussing percentages. 

Example:

"50% of the students in the class passed the exam, so more than half of the students in the class passed." This argument is flawed because we don't know the total number of students; a small class might have a high percentage of students passing, but still have fewer than half passing in a larger class.


300

What is a Logical Force (Modality/Quantification) Flaw?

occurs when an argument incorrectly assumes or generalizes beyond the strength of the premises' logical force

Pay attention to keywords: 

Look for words like "all," "none," "every," "some," "must," "always," "never," "likely," "possible," etc

Example: Some students study for the LSAT, therefore, all students study for the LSAT." (This is a flaw because "some" is weak, and the conclusion is strong

400

What is a whole to part flaw?

occurs when an argument incorrectly assumes that because something is true of the whole, it's also true of each individual part, or vice versa

Look for arguments that jump from a statement about a group to a statement about each member of that group, or vice versa 

Examples: 

  • The car dealership has the best customer service, therefore, every car I buy from that dealership will have no issues". 
  • (Students): "The school has a high graduation rate, therefore, every student will graduate."


400

What is a Sufficiency and Necessity Flaw?

occurs when an argument incorrectly assumes that a condition, which is necessary for something to happen, is also sufficient to guarantee it, or vice versa

1) Fallacy of the converse

  • Conditional Statement: "If P, then Q" (e.g., "If it's raining, then the ground is wet"). 
  • Converse: "If Q, then P" (e.g., "If the ground is wet, then it's raining"). 
  • Fallacy: Assuming the converse is true just because the original conditional statement is true. There are many other reasons for why the ground might be wet. We just don't know


2) Fallacy of the inverse

  • Premise: "If it's raining (P), then the ground is wet (Q)." 
  • Fallacious Conclusion: "It's not raining (not P), therefore the ground is not wet (not Q)." Once again, just because it is not raining, doesn't mean that the ground is not wet for other reasons


400

What is a Perception vs. Reality Flaw?

occurs when an argument mistakenly assumes that someone's perception or belief about something is a reflection of reality, even when that person is not an authority on the topic or their perception is demonstrably flawed

Look for arguments that cite an opinion or belief as evidence for a conclusion, especially when the person holding the opinion is not an expert on the subject or their perception is demonstrably wrong.

Example 1: An argument claims that because a celebrity endorses a product, it must be good, ignoring the fact that the celebrity's endorsement is based on their perception and not necessarily on the product's actual quality

500

What is an Equivocation an Flaw?

Occurs when an argument uses a word or phrase with two different meanings, creating a false or misleading connection between them

Look for arguments that use the same word or phrase multiple times but in different contexts, where the meaning changes

Example: 

A piece of paper is light. What is light cannot be dark. Therefore, a piece of paper cannot be dark. The word “light” is first used in this example as the opposite of “heavy.” Then it is used as a synonym for “bright.” Thus, we have an equivocal language flaw because we are faced with two words masquerading as one.
500

What is a Comparison Flaw?

The argument compares two things without considering all relevant factors. Why this is a flaw: Just because a Honda Civic is more comfortable than a Lamborghini doesn't mean it's a better car. Think about this if the argument: Compares two things or uses an analogy.

  • Look for arguments that compare two things and then draw a conclusion about one based on the other, without considering relevant differences. 
  • Think about whether the comparison is fair or if there are other factors that could explain the conclusion.

Example: 

  • "Company A's new product has a sleek design, like Company B's product. Therefore, Company A's product is also as durable as Company B's product." 
  • Flaw: The argument assumes that because the products share one similarity (sleek design), they must also share another (durability), without considering that they might be made of different materials or have different manufacturing processes.
500

What is a Circular Reasoning (Rare) Flaw?

Argument's conclusion simply restates one or more of the premises.

Example: Duplicity is an unattractive characteristic, since it's repulsive to lie and deceive.