Flaw Questions

Many books start teaching LR sections with this question type, and for good reason. Flaw questions are among the most prominent in every LR section. Not understanding how to solve them means losing a lot of points. The bright side: once you understand them, you can reliably grab all those points back.

The fun thing is that identifying flaws in arguments is probably something you will be doing every day as a lawyer too. So think of this as early career training.

Identifying the Question Type

The most common question stems are:

The reasoning in the argument is most vulnerable to criticism on the grounds that the argument...
Which one of the following most accurately describes a flaw in the reasoning?

Sometimes the stem refers directly to the person making the argument in the stimulus:

The politician's reasoning is flawed because she presumes without giving sufficient justification that...
The politician's argument is flawed because her argument fails to consider...
The politician's reasoning is questionable because she overlooks the possibility that...
The politician's reasoning is questionable because she takes for granted that...

The trend is consistent across all of them: you are being asked to critique the reasoning, not just react to it. This is different from everything we have done so far. With Strengthen and Weaken questions, we took the argument as given and found answer choices that affected its plausibility. With Flaw questions, we are critiquing the reasoning process itself.

The General Strategy

Many books give you a list of common flaws and ask you to memorize them. I am not a fan of that approach. It works when it works, but when it does not, it can blow up in your face. I will give you that list later in this chapter, but first I want to teach you a strategy that is far more generalizable.

Once you have read the question stem and confirmed it is a Flaw question, read the stimulus and highlight the conclusion as always. Then, before reading the answer choices, anticipate the flaw.

The way to do this is to look for a REASONING GAP between the premises and the conclusion. The argument is claiming that these premises lead to this conclusion. Your job is to find what it is overlooking or assuming. To construct the REASONING GAP, start with one of these three phrases:

What if...
The argument fails to consider...
The argument takes for granted...

Let's go back to the Tim Hortons example:

Goku will always go to Tim Hortons on Sundays for coffee. Today is Saturday. Therefore, Goku will go to Tim Hortons tomorrow morning.

The premises are: (1) Goku always goes to Tim Hortons on Sundays, and (2) today is Saturday. The conclusion is: Goku will go tomorrow.

We use the three phrases above to construct a REASONING GAP:

What if Goku died on Saturday?
The argument fails to consider that Goku may get hit by a bus on Saturday.
The argument takes for granted that Goku will still be alive on Sunday.

Obviously the answer choices may not mention Goku getting hit by a bus. But now you know the shape of the flaw: something could happen to Goku on Saturday that makes it impossible for him to go on Sunday. When you read the answer choices, you are looking for something that generalizes that reasoning gap.

Which Phrase Should I Use?

Honestly, you can use any of the three. But sometimes one is more useful than the others, especially when the question stem gives you a hint.

"Fails to consider": Whatever you fill in here should be something that would weaken the argument. If this were a Weaken question, the thing you fill in would be a great weakener. Use this phrase when the question stem says things like:

The argument fails to consider that...
The argument ignores the possibility that...

"Takes for granted": Whatever you fill in here is something the argument implicitly assumes but never explicitly states. The argument needs it to be true for the conclusion to work, but it never says so out loud. Use this phrase when the question stem says things like:

The argument presumes without giving sufficient justification that...
The argument is vulnerable because it takes for granted that...

"What if": This one is the most versatile. You can fill it with something that weakens the argument or something the argument assumes. Because it covers both cases, I typically default to "What if" and only switch to one of the above two if the question stem specifically calls for it.

At the end of the day, all three phrases are doing the same thing. Pick whichever helps you think most clearly.

A Full Example

Literary critic: Reviewers who praised Ananya's debut fiction novel overwhelmingly had themselves published fiction. Reviewers who had not published fiction were far more likely to find the novel self-indulgent and structurally weak. The praise for Ananya's novel therefore reflects nothing more than professional solidarity among fiction writers, and should be discounted accordingly.

Conclusion: "The praise for Ananya's novel reflects nothing more than professional solidarity among fiction writers, and should be discounted accordingly."

Now we anticipate the flaw. The argument is saying we should not take the praise seriously because the people giving it were fiction writers.

My REASONING GAP: What if fiction writers are actually better judges of fiction than non-fiction writers?

Equally valid versions:

Fails to consider that fiction writers may be better positioned to evaluate fiction.
Takes for granted that non-fiction writers are less qualified than fiction writers to judge a fiction novel.

All three expose the same gap: if fiction writers are the most qualified judges of fiction, then their praise is exactly what we should be paying attention to, not discounting.

Now the answer choices:

A. draws a conclusion about the merit of a novel from evidence that concerns only the motives of the people evaluating it

B. presupposes that professional solidarity is the only factor capable of producing agreement among reviewers who share a background

C. takes for granted that the proportion of reviewers who praised the novel is large enough to warrant a conclusion about the reviewing community as a whole

D. fails to consider that reviewers who have published fiction may be better positioned to evaluate its qualities than those who have not

E. fails to consider that reviewers who have not published non-fiction are more objective than those who have

Click to reveal

Answer Choice	Explanation
A	The argument never discusses the motives of the reviewers at all. And this is nowhere near the flaw we anticipated. Eliminate.
B	"Presupposes that" signals an implicit assumption. Does the argument ever assume that professional solidarity is the only possible explanation for such agreement? No. The argument applies this reasoning to this specific case, but never makes a general claim about it being the only factor. Not close to our anticipated flaw. Eliminate.
C	"Takes for granted" signals an implicit assumption. Does sample size affect the validity of this argument? Not really. The argument does not depend on how many reviewers there were. Eliminate.
D	"Fails to consider" signals that what follows should weaken the argument. In this case, does it? Absolutely. If fiction writers are better positioned to evaluate fiction, then their praise is meaningful and should not be discounted. This matches our anticipated flaw exactly. Keep.
E	"Fails to consider" again. Is the argument getting weakened with what follows? No, it actually strengthens it by suggesting non-fiction reviewers are more objective, which would support discounting the fiction writers' praise. Eliminate.

After analyzing each answer choice, we pick Option D.

Two Flavours of Flaw Questions

Before we move on to the common flaws list, it is worth noting that Flaw questions come in two varieties.

Flavour 1: The answer choices refer directly to the characters and content of the stimulus. The Ananya example above is this type. You find the REASONING GAP, and then look for an answer choice that describes it using the same people and things from the stimulus.

Flavour 2: The answer choices are written in abstract, technical language with no reference to the stimulus at all. You still find the same REASONING GAP, but then you have to match it to a generalized description of that flaw. This is where the common flaws list becomes useful.

The exercise is still the same in both situations. Find the REASONING GAP first. Then find the answer choice that describes it, whether it does so with stimulus-specific language or in technical terms.

The Common Flaws

A common flaw is just a REASONING GAP that appears so frequently that the answer choices sometimes describe it in technical language rather than relating it back to the stimulus. Below are the most important ones. For each, I give you the definition, an example, the REASONING GAP, and both how a direct answer choice would describe it and how a technical answer choice would describe it.

1. Conditional Reasoning Flaw

What it is: The argument makes an invalid inference from a conditional statement, typically by confusing the sufficient and necessary conditions.

Example:

All people who play League of Legends are cool. Harsh does not play League of Legends. Therefore, he is not cool.

We have: Play League of Legends Cool. The argument then says the sufficient condition is false (Harsh does not play) and concludes the necessary condition is also false. But we know from our conditional reasoning chapters that a false sufficient condition allows us to conclude nothing.

REASONING GAP: What if Harsh has other qualities that make him cool?

Direct answer choice: The argument presumes without justification that Harsh may not possess any other qualities that would make him cool.

Technical answer choice:

takes a sufficient condition to be a necessary condition
confuses a sufficient condition with a necessary one

2. Correlation Is Not Causation

What it is: Just because two things happened at the same time (when this happens, we say the two things are correlated), that does not mean that one thing caused the other.

Example:

Over the last month, it has rained every Friday. Tomorrow is Friday, so it has to rain tomorrow.

REASONING GAP: What if raining on Fridays over the last month is just a coincidence?

Direct answer choice: Fails to consider that raining on Fridays may just be a coincidence.

Technical answer choice:

infers a cause from a mere correlation
fails to establish that the phenomena interpreted as cause and effect are not both effects of some other factor

3. Part-Whole Confusion

What it is: The argument assumes that what is true of the members of a group must be true of the group as a whole, or vice versa.

Example:

Every player on the team is talented. Therefore, the team is talented.

REASONING GAP: What if the players do not work well together, making the team ineffective despite individual talent?

Direct answer choice: Fails to consider that a group of talented individuals may not function as a talented team.

Technical answer choice:

illegitimately infers a property of the whole from a property of its parts
assumes that what holds for each member of a group must hold for the group itself

The following statement also commits this flaw, but in reverse:

Example:

This team is the best in the league. Therefore, the best player in the league must also belong to the team.

REASONING GAP: What if the best player in the league is in a different team?

Direct answer choice: Fails to consider that the best player in the league may belong to a different team

Technical answer choice:

illegitimately infers a property of the parts from a property of the whole
assumes that what holds for the group must hold for each member of it

4. Straw Man

What it is: The argument misrepresents an opponent's position in order to attack it more easily.

Example:

Akshat says we should reduce sugar in school lunches. The principal responds: Akshat wants to ban all food from schools, which is absurd.

REASONING GAP: Fails to consider that the principal is attacking a position Maya never actually held.

Direct answer choice: Fails to consider that the position being attacked is not the position that was actually stated.

Technical answer choice:

attacks an argument different from the one actually offered
attacks a distorted version of the opposing view rather than the view as actually stated

5. Ad Hominem

What it is: The argument attacks the person making a claim rather than the claim itself.

Example:

You should not trust Dr. Gilani's research on climate change — he drives an SUV.

REASONING GAP: What if Dr. Gilani's personal behaviour has no bearing on whether her research is correct?

Direct answer choice: Fails to consider that personal behaviour is irrelevant to the validity of someone's research.

Technical answer choice:

rejects a claim on the basis of facts about the person who made it rather than on the merits of the claim itself
attacks the source of an argument rather than its content

6. Circular Reasoning

What it is: The argument uses its conclusion as one of its premises, essentially assuming what it is trying to prove.

Example:

My book is correct because it says so in the book.

(I censored myself here for this example. Pick you least favourite book to make this more interesting.)

REASONING GAP: Fails to consider that the only support for the conclusion is the conclusion itself restated.

Direct answer choice: Fails to provide any independent evidence for the claim it is attempting to establish.

Technical answer choice:

assumes the truth of what it sets out to prove
the conclusion is merely a restatement of one of the premises

7. Equivocation

What it is: The argument uses the same word in two different senses to reach a conclusion.

Example:

The sign said "fine for parking here," so I parked there since it was fine to do so.*

REASONING GAP: What if "fine" means a monetary penalty on the sign, not that parking there is acceptable?

Direct answer choice: Fails to consider that the word used in the sign has a different meaning from the one assumed.

Technical answer choice:

relies on an ambiguous use of a key term
the conclusion depends on shifting the meaning of a term between premises

8. Inappropriate Appeal to Authority

What it is: The argument tries to establish a conclusion by appealing to someone whose authority is irrelevant to the claim being made.

Example:

You should believe that climate change is a serious threat — Stephen Hawking said so, and he was the greatest physicist of his generation.

REASONING GAP: What if expertise in physics has no bearing on whether someone is qualified to make authoritative claims about climate science?

Direct answer choice: Fails to consider that the person cited may not have relevant expertise in the field the conclusion is about.

Technical answer choice:

supports its conclusion by appeal to authority rather than evidence
the authority invoked lacks expertise in the field to which the conclusion pertains

9. Faulty Sampling

What it is: The argument draws a broad conclusion from a sample that is too small, unrepresentative, or biased.

Example:

I asked five of my friends if they liked anime and they all said yes. Thus, most people must love anime.

REASONING GAP: What if five friends are not a representative sample of most people?

Direct answer choice: Fails to consider that the sample surveyed may not be representative of the broader population.

Technical answer choice:

generalizes from a sample that is too small to support the conclusion
the sample on which the conclusion is based is unrepresentative of the group to which it is applied

10. Irrelevant Evidence

What it is: The argument uses evidence that has no logical connection to the conclusion being drawn.

Example:

This restaurant has been open for 50 years, so the food must be delicious.*

REASONING GAP: What if a restaurant's age tells us nothing about the quality of its food?

Direct answer choice: Fails to establish a logical connection between the evidence offered and the conclusion drawn.

Technical answer choice:

bases its conclusion on considerations that are logically irrelevant to it
the premises, even if true, provide no support for the conclusion

11. Number-Percentage Confusion

What it is: The argument confuses raw numbers with rates or percentages, treating one as evidence for the other.

Example:

More people die from car accidents in Canada than in Iceland, so driving must be more dangerous in Canada.

REASONING GAP: What if Canada simply has a far larger population, meaning the rate of car accident deaths could actually be lower?

Direct answer choice: Fails to consider that a higher absolute number does not establish a higher rate when the populations being compared are very different in size.

Technical answer choice:

treats a claim about absolute quantities as evidence for a claim about proportions
conflates a difference in totals with a difference in rates

12. Internal Contradiction

What it is: The argument's own premises conflict with each other or with its conclusion.

Example:

No one can truly be selfless. And that is why we should all admire Mother Teresa for her selfless dedication.*

REASONING GAP: Fails to consider that claiming selflessness is impossible directly contradicts praising someone for being selfless.

Direct answer choice: Fails to recognize that one of its own premises is inconsistent with its conclusion.

Technical answer choice:

relies on premises that are mutually inconsistent
the conclusion is undermined by a commitment made elsewhere in the argument

13. Possibility vs. Certainty

What it is: The argument treats something that could happen as though it will definitely happen, or treats something that might be true as though it must be true.

Example:

It is possible that the new policy will reduce crime. Therefore, we should defund the police as we expect crime to decrease.

REASONING GAP: What if the mere possibility that something could occur gives us no grounds to treat it as a certainty?

Direct answer choice: Fails to consider that a possible outcome is not the same as a guaranteed one.

Technical answer choice:

infers that something will occur from the mere fact that it could occur
treats a claim that is merely possible as if it were established as certain

14. False Dichotomy

What it is: The argument presents two options as if they are the only possibilities when others exist.

Example:

Either you support this war, or you hate your country. You do not support this war, so you hate your country.

REASONING GAP: What if there are other positions available beyond the two the argument presents?

Direct answer choice: Fails to consider that there may be options beyond the two it treats as exhaustive.

Technical answer choice:

presumes without justification that the choices available are limited to two
treats a false dilemma as if the alternatives presented were mutually exclusive and jointly exhaustive

15. Lack of Proof

What it is: The argument treats the absence of evidence against something as proof that it is true, or treats the absence of evidence for something as proof that it is false.

Example:

No one has ever proven that ghosts do not exist. Therefore, ghosts must exist.

REASONING GAP: What if the failure to disprove something tells us nothing about whether it is actually true?

Direct answer choice: Fails to recognize that the absence of evidence against a claim is not the same as evidence in favour of it.

Technical answer choice:

infers the truth of a claim from the mere absence of evidence against it
treats a failure to disprove as equivalent to proof

BREATHE. IT IS OKAY. BREATHE.

I know that was a lot. You will get used to it. Some of these — conditional reasoning flaws, correlation vs. causation, part-whole confusion, and faulty sampling — show up far more often than others. You will get very good at recognizing those quickly.

Others you will see rarely. But at least now you know what they mean. For the longest time I had no idea what equivocation meant and would panic whenever it showed up in an answer choice. Now you have a definition and an example, so that never needs to happen to you.

Do not spend too much time trying to memorize this list. If you have a strong, intuitive grasp of the REASONING GAP construction using "What if," "fails to consider," or "takes for granted," that matters far more than knowing these labels cold. The list is a reference, not a memorization target.

Let's quickly go over the typical wrong answer choices for flaw questions.

Wrong Answer Choices

Beyond the Scope: The answer choice talks about something not present in the stimulus. Since a flaw is a critique of the reasoning process, the correct answer can only reference things that actually appear in the argument.

Incorrect Flaw: The answer choice describes a real flaw, just not the one the argument commits. For example, if the argument makes a conditional reasoning error and you select an answer choice saying "infers the truth of a claim from the mere absence of evidence against it" — that is a real flaw (lack of proof), but it is not what this argument did wrong.

Not a Flaw: The answer choice describes an inference that is actually valid. For example, we are allowed to infer A C if we know A B C. If an answer choice says the argument fails because it inferred C from A, that answer choice is wrong because that inference is perfectly legitimate.

Weak Flaw: The answer choice identifies something the argument could be doing wrong, but the correct answer captures a more obvious and direct error in the reasoning. When two options both seem like flaws, the one that cuts closer to the core of the argument wins.

Except Alert

Except versions of Flaw questions are rare, but worth knowing about. A stem might say:

The argument is flawed because it overlooks each of the following possibilities EXCEPT:

Here, four answer choices would each correctly identify something the argument overlooks (a real flaw or vulnerability), and one would not. That one outlier describes something the argument does NOT actually overlook, either because the argument already addresses it or because it was never relevant to the argument in the first place.

In this case, you are not anticipating a single REASONING GAP ahead of time. Instead, go through each answer choice and ask: does the argument actually fail to consider this? Four of them will be genuine gaps in the argument. The one that is not a genuine gap is your answer.

TL;DR

Read the question stem and know its a identify the flaw question.
Know the stimulus will be an argument and go in looking for the conclusion.
Read the stimulus and highlight the main conclusion.
Anticipate the flaw by constructing it using either What if, fails to consider or takes for granted.
Read each answer choice, finding one that matches the ancipated flaw.

EZ!

Now go practice.

GLHF!