chapter04

Getting Familiar

To start, go ahead and try these four Identify the Flaw questions. Give yourself no more than six minutes total. We'll revisit these questions later on in the chapter.

PT36, S1, Q12

The consumer price index is a measure that detects monthly changes in the retail prices of goods and services. The payment of some government retirement benefits is based on the consumer price index so that those benefits reflect the change in the cost of living as the index changes. However, the consumer price index does not consider technological innovations that may drastically reduce the cost of producing some goods. Therefore, the value of government benefits is sometimes greater than is warranted by the true change in costs.

The reasoning in the argument is most vulnerable to the criticism that the argument

(A) fails to consider the possibility that there are years in which there is no change in the consumer price index

(B) fails to make explicit which goods and services are included in the consumer price index

(D) uncritically draws an inference from what has been true in the past to what will be true in the future

(E) makes an irrelevant shift from discussing retail prices to discussing production costs

PT14, S2, Q22

Gallery owner: Because this painting appears in no catalog of van Gogh's work, we cannot guarantee that he painted it. But consider: the subject is one he painted often, and experts agree that in his later paintings van Gogh invariably used just such broad brushstrokes and distinctive combinations of colors as we find here. Internal evidence, therefore, makes it virtually certain that this is a previously uncataloged, late van Gogh, and as such, a bargain at its price.

The reasoning used by the gallery owner is flawed because it

(A) ignores the fact that there can be general agreement that something is the case without its being the case

(B) neglects to cite expert authority to substantiate the claim about the subject matter of the painting

(D) provides no evidence that the painting is more likely to be an uncataloged van Gogh than to be a painting by someone else who painted that particular subject in van Gogh's style

(E) attempts to establish a particular conclusion because doing so is in the reasoner's self interest rather than because of any genuine concern for the truth of the matter

PT34, S2, Q9

A university study reported that between 1975 and 1983 the length of the average workweek in a certain country increased significantly. A governmental study, on the other hand, shows a significant decline in the length of the average workweek for the same period. Examination of the studies shows, however, that they used different methods of investigation; thus there is no need to look further for an explanation of the difference in the studies’ results.

The argument's reasoning is flawed because the argument fails to

(A) distinguish between a study produced for the purposes of the operation of government and a study produced as part of university research

(B) distinguish between a method of investigation and the purpose of an investigation

(D) recognize that two different methods of investigation can yield identical results

(E) recognize that varying economic conditions result in the average workweek changing in length

PT32, S1, Q10

To accommodate the personal automobile, houses are built on widely scattered lots far from places of work and shopping malls are equipped with immense parking lots that leave little room for wooded areas. Hence, had people generally not used personal automobiles, the result would have to have been a geography of modern cities quite different from the one we have now.

The argument's reasoning is questionable because the argument

(A) infers from the idea that the current geography of modern cities resulted from a particular cause that it could only have resulted from that cause

(B) infers from the idea that the current geography of modern cities resulted from a particular cause that other facets of modern life resulted from that cause

(C) overlooks the fact that many technological innovations other than the personal automobile have had some effect on the way people live

(D) takes for granted that shopping malls do not need large parking lots even given the use of the personal automobile

(E) takes for granted that people ultimately want to live without personal automobiles

Introduction

Let's begin this chapter by evaluating a simple argument:

Cats are friendlier than dogs.

Cats make for the best pets.

What's wrong with this argument? Perhaps you might think…

No! Dogs are friendlier than cats.
Cats and dogs are about as friendly as one another.
There is no accurate way to measure the friendliness of animals.
Friendliness is not the primary consideration for what makes a best pet.
There are other characteristics aside from friendliness, such as loyalty, that help determine a best pet.
Dogs make for the best pets.
There are pets other than cats and dogs that ought to be considered.
There is no way to crown a definitive “best pet.”

All of these criticisms of the argument could, in real life, be valid. However, only some of these are representative of the types of reasoning flaws that you are typically asked to identify on the LSAT. Take a look through the list again if you'd like and see if you can determine which ones represent reasoning flaws.

For Identify the Flaw questions, you are not being asked to evaluate the validity of the premises, nor are you being asked, in any direct way, to evaluate the validity of the conclusion in and of itself. Rather, your task is to identify flaws in the relationship between the premises and the conclusion.

If you analyze the eight typical reactions above, you should see that the first three seem to question the validity of the premise on its own. #6 and #8 seem to question the validity of the conclusion on its own. Only #4, #5, and #7 represent flaws that call the relationship between the premise and the conclusion into question. These are the types of flaws you are consistently asked to identify on the LSAT.

If the previous few chapters have helped you get stronger at recognizing issues between premises and conclusion, this chapter should add to and reinforce that understanding. The reasoning skills required for Identify the Flaw questions are almost identical to those required for Assumption questions. In fact, these two question types can be considered two sides of the same coin.

It's a Flaw to Assume

For both Assumption and Identify the Flaw questions, we are expected to evaluate the connection between the evidence presented and the conclusion reached. There will always be a gap in this connection, and any such gap can be considered either as an unstated assumption or a flaw.

Let's use the earlier example to illustrate:

Cats are friendlier than dogs.

Cats make for the best pets.

The author is making several assumptions in using this premise to support this conclusion, and most likely some of these assumptions are pretty obvious to you. He's assuming that friendliness is what determines a best pet (perhaps loyalty, intelligence, obedience, or protectiveness are factors). He's also assuming that there aren't animals other than cats and dogs that warrant consideration. Consider how an assumption can be presented as a flaw with just a few changes in wording:

“The author assumes that friendliness is the primary characteristic that defines a best pet.”

Can be changed to…

“The author takes for granted that friendliness is the primary characteristic that defines a best pet.”

“The author assumes no other pets need to be considered for best pet.”

Can be changed to…

“The author fails to consider other pets for best pet.”

Therefore, the work you've put into mastering Assumption questions should serve you well for Identify the Flaw questions. Remember that, in a general sense, assumptions play two broad roles—they either help to match up the premises and the conclusion (How does friendliness relate to best pet?), or they address other considerations relevant to the conclusion (What other pets need to be considered?).

We can use our understanding of these roles to shape how we think of Identify the Flaw questions. The right answer to any Identify the Flaw question will address one or both of the following concerns:

Is there a premise–conclusion mismatch?
What other factors has the author failed to consider in reaching his or her conclusion?

Let's discuss both issues in depth.

1. Is There a Premise–Conclusion Mismatch?

In the last chapter, we discussed “term” and “concept” shifts. Note that there will always be term and concept shifts between the premises and the conclusion (otherwise we'd just have the same sentence written twice!). What we want to be on the lookout for are the term or concept shifts that are significant enough to make us doubt that the premise is sufficient to validate the conclusion.

Here are a few examples of term and concept shifts that would be significant enough to warrant our suspicion:

P: People who floss regularly tend to have fewer gum problems later in life.
C: If you'd like to have fewer gum problems later in life, we recommend that you floss daily.
Who knows if daily flossing is the type of regular flossing that is good for you? Maybe flossing every 12 hours, or alternatively every three days, is the key.

P: The majority of voters will be Democrats.
C: Therefore, the Democratic candidate will receive the most votes.
Who knows if the Democratic voters will vote for this Democratic candidate?

P: Some of the judges were surprised by the flavors in the cake.
C: It's likely that they will give it a low score.
Maybe they were pleasantly surprised?

P: There are a lot more boys in this year's class than there were in last year's.
C: The girls will constitute a smaller proportion of this year's class.
For now, we'll leave it up to you to figure out what's wrong here.

If you are having trouble seeing these mismatches, there will be many more examples to come. If you think you've got it, great. Chances are, if you see a mismatch like this, the right answer will address it in one way or another. Now, the next thing to consider is, “How do the test writers make it more of a challenge to identify this mismatch?”

Let's use an example from earlier to discuss:

PT36, S1, Q12

The reasoning in the argument is most vulnerable to the criticism that the argument

(A) fails to consider the possibility that there are years in which there is no change in the consumer price index

(B) fails to make explicit which goods and services are included in the consumer price index

(D) uncritically draws an inference from what has been true in the past to what will be true in the future

(E) makes an irrelevant shift from discussing retail prices to discussing production costs

We are asked to identify the criticism to which the argument is MOST vulnerable. Keep in mind that typically, even when an Identify the Flaw question is asked in relative terms—“most vulnerable” seems to indicate that we may compare multiple flaws—there will be just one answer choice that actually represents a flaw in the argument.

Let's model the reading process as it might play out in real time:

The consumer price index is a measure that detects monthly changes in the retail prices of goods and services.

This is background information. The argument is about the consumer price index.

The payment of some government retirement benefits is based on the consumer price index so that those benefits reflect the change in the cost of living as the index changes.

This is also background. This sentence links the consumer price index to government retirement benefits.

However, the consumer price index does not consider technological innovations that may drastically reduce the cost of producing some goods.

The “however” sets up a contrast—the consumer price index doesn't consider this other factor. It's unclear at this point why this contrast is important.

Therefore, the value of government benefits is sometimes greater than is warranted by the true change in costs.

This is definitely the author's main point.

In terms of the general structure of the argument, what we have is background-background-counter to that background-“therefore” a conclusion. The conclusion is a consequence of the previous sentence:

“However, the consumer price index does not consider technological innovations that may drastically reduce the cost of producing some goods.”

At this point, we have a sense of the argument core:

Consumer price index doesn't consider tech innovations that may drastically reduce cost of producing some goods.

Value of government benefits sometimes greater than is warranted by true change in costs.

It is often true, particularly for challenging questions, that even though the reasoning issues are in the core, the key to understanding these issues lies outside the core. That is, it is in the other information (the background, or opposing points) that we come to understand the significance of issues in the core.

What is the relevance of this premise to the conclusion? Well, the benefits are based on the consumer price index. The author is saying there is a problem here—the consumer price index doesn't represent potential reductions in production costs.

Is this really a problem? In the background information, we learn that benefits are based on the index so that they reflect changes in the cost of living. This makes perfect sense. After all, the benefits are presumably meant to be used for living costs. Are the benefits flawed because the index doesn't reflect production costs?

No. It's not. And there's the gap. The author inserts production costs into an argument that doesn't seem to warrant discussion of that factor.

Ideally, for most Identify the Flaw questions, you want to go into the answer choices with this type of very clear sense of what the flaw or flaws are in an argument. Even so, as you evaluate the answers, you want to make sure to work from wrong to right. That is, even if you have a strong prediction about the right answer, you want to, in your first time through the answer choices, be on the lookout for reasons why four of the five answers are wrong. This is the most effective and efficient way to arrive at the right choice.

Let's rewrite the core here and evaluate the answer choices one at a time:

Consumer price index doesn't consider tech innovations that may drastically reduce cost of producing some goods.

Value of government benefits sometimes greater than is warranted by true change in costs.

(A) fails to consider the possibility that there are years in which there is no change in the consumer price index

Whether the index varies or stays the same has no direct bearing on whether production costs should be reflected in retirement benefits. We can eliminate this quickly.

(B) fails to make explicit which goods and services are included in the consumer price index

This also has no direct bearing on the core. We don't need to know about every single item on the index in order to evaluate this particular argument involving the index. We can eliminate this quickly.

This answer choice connects to the core in an interesting albeit indirect way—we can imagine that the consumer price index might be based on items that are usually purchased. Still, this answer choice has no direct bearing on the conclusion. Whether benefits are used for usual or unusual goods has no direct impact on whether production costs should be reflected in retirement benefits.

(D) uncritically draws an inference from what has been true in the past to what will be true in the future

This argument does not use evidence from the past to claim that something will be true in the future. We can quickly eliminate this too.

We're down to just one:

(E) makes an irrelevant shift from discussing retail prices to discussing production costs

This is the answer we anticipated. The fact that the consumer price index doesn't reflect changes in production costs is irrelevant to the issue of how the consumer price index is used to set benefits.

Consider now how the writers made it more of a challenge for you to identify the mismatch in the core. One challenge was the volume of information—it was imperative that you prioritized correctly. The second was that, in order to fully understand the elements discussed in the core, we had to reference the background information.

Let's take a look at another example. See if you can spot the significant shift between the premises and the conclusion in the argument before you evaluate the answer choices.

PT16, S3, Q24

A birth is more likely to be difficult when the mother is over the age of 40 than when she is younger. Regardless of the mother's age, a person whose birth was difficult is more likely to be ambidextrous than is a person whose birth was not difficult. Since other causes of ambidexterity are not related to the mother's age, there must be more ambidextrous people who were born to women over 40 than there are ambidextrous people who were born to younger women.

The argument is most vulnerable to which one of the following criticisms?

(A) It assumes what it sets out to establish.

(B) It overlooks the possibility that fewer children are born to women over 40 than to women under 40.

(D) It does not state how old a child must be before its handedness can be determined.

(E) It neglects to explain how difficulties during birth can result in a child's ambidexterity.

What's the author's conclusion?

…there must be more ambidextrous people who were born to women over 40 than there are ambidextrous people who were born to younger women.

How does he try to prove it? In this case, we can see that there are two premises that work together to support the conclusion:

A birth is more likely to be difficult when the mother is over the age of 40 than when she is younger.

and…

A person whose birth was difficult is more likely to be ambidextrous than is a person whose birth was not difficult.

Thus, we can think about the core as follows:

Over-40 mother more likely to have difficult birth than when younger.
+
A person with difficult birth more likely to be ambidextrous.

More ambidextrous people born to women over 40 than to younger women.

Do you notice the mismatch? Think about it before reading on.

From these two premises, what can we conclude about people who are born to women over 40? Perhaps mothers over 40 are more likely to give birth to ambidextrous children, but that does not have to mean that they will be giving birth to a greater number of ambidextrous children. Notice that the conclusion is about the total number. Whether mothers over 40 give birth to a greater number of children would also depend on the proportion of children who are born to women over 40. If 50 percent of all children are born to women over 40, this argument makes a lot of sense. If 1% of all children are born to women over 40, well, the argument becomes significantly more dubious.

The point is not that you need to come up with hypothetical situations (though they can often be helpful in clarifying the specific mismatch). More important is that we recognize the mismatch between a likelihood and a total number, and that we recognize that the author has assumed a direct connection where there isn't one.

The correct answer, (B), reflects the consequences of this mismatch.

(B) It overlooks the possibility that fewer children are born to women over 40 than to women under 40.

None of the other answer choices address the gap between likelihood and amount.

Let's look back at an example we presented earlier:

P: There are a lot more boys in this year's class than there were in last year's.

C: The girls will constitute a smaller proportion of this year's class.

In this case, notice that the premise is about actual numbers, and the conclusion is about a proportion. As in the previous problem, this leads to a mismatch. We know nothing about the number of girls in this year's class—perhaps it has increased too, even more than the number of boys. In that case, the conclusion about the proportion could be incorrect.

The faulty link between proportion and amount is just one of the many issues that can be more easily spotted if you are consistently on the lookout for mismatches between the premise and the conclusion.

Now let's discuss the second of our primary concerns.

2. What Else Needs to Be Considered in Order to Evaluate the Conclusion?

Let's start this part of the discussion by evaluating another simple argument:

Janice is strong.

Janice is athletic.

Hopefully, you are reading with a critical eye and can see immediately that this argument is flawed. You can say that the flaw has to do with a mismatch between premise and conclusion—strong and athletic are not the same thing—and that would be 100% correct.

Another way to think about this flaw is that being strong is just one part of being athletic. What we commonly consider as being athletic often also entails speed and coordination, along with other traits. Many LSAT arguments are flawed because the author considers only one or two of what ought to be many determining factors.

Let's look at another simple example:

Janice is strong.

She must work out daily.

This is also a flawed argument because the author failed to consider alternatives, but in this case, it's a different type of consideration that has been forgotten: for what other reasons, and through what other means, could she be or get strong? Maybe she was born strong. Maybe she takes supplements to build muscle mass. We can't ignore these possibilities.

Take a look at one more argument. Identify the core, and try to figure out what else might be relevant to the conclusion.

PT19, S4, Q3

The number of calories in a gram of refined cane sugar is the same as in an equal amount of fructose, the natural sugar found in fruits and vegetables. Therefore, a piece of candy made with a given amount of refined cane sugar is no higher in calories than a piece of fruit that contains an equal amount of fructose.

We can think of the argument core as follows:

What is the author failing to consider? Think about it for a second before reading on.

A piece of candy is going to have calories that come from ingredients other than sugar. A piece of fruit will have calories that come from elements other than fructose. That is, calories from sugar are just one part of the total calories for a piece of candy, and calories from fructose are just one part of the total calories for a piece of fruit. Maybe the other ingredients in the candy have a lot more calories than the non-fructose parts of the piece of fruit.

Let's take a look at the answer choices that came with this argument. Evaluate each one relative to the core before reading the comments.

(A) fails to consider the possibility that fruit might contain noncaloric nutrients that candy does not contain

Most of this answer sounds attractive, but since we're concerned with the number of calories, noncaloric nutrients are of no consequence.

(B) presupposes that all candy is made with similar amounts of sugar

We're comparing candy and fruit with equivalent amounts of sugar and fructose rather than, say, two pieces of candy made with unknown amounts of sugar, and therefore the author does not need to assume this to be true.

This is not the case. Notice it has little to do with our core.

(D) presupposes what it sets out to establish, that fruit does not differ from sugar-based candy in the number of calories each contains

What this answer means is that the argument is using the conclusion to justify the conclusion. This is not the case. Furthermore, the actual conclusion is not simply comparing the calories in fruit and candy, but in a piece of fruit and a piece of candy that have respectively equal amounts of fructose and sugar.

(E) overlooks the possibility that sugar might not be the only calorie-containing ingredient in candy or fruit

This is the answer we anticipated, and it is correct. The primary flaw in this argument was a failure to consider other relevant issues.

Now let's look back at an example from earlier in the chapter. Try solving it again if you'd like, and make sure to identify the flaw before moving on to the answer choices.

PT14, S2, Q22

The reasoning used by the gallery owner is flawed because it

(A) ignores the fact that there can be general agreement that something is the case without its being the case

(B) neglects to cite expert authority to substantiate the claim about the subject matter of the painting

(D) provides no evidence that the painting is more likely to be an uncataloged van Gogh than to be a painting by someone else who painted that particular subject in van Gogh's style

(E) attempts to establish a particular conclusion because doing so is in the reasoner's self interest rather than because of any genuine concern for the truth of the matter

The gallery owner's ultimate point is that the painting is a bargain at its price (by the way, what price?). How does he get there? Through the use of an intermediate conclusion: evidence makes it almost certain that the work is indeed a van Gogh. What's the evidence? The subject matter, stroke style, and color combinations match those of his other works.

We can think of the argument core as follows:

In this argument, there are significant assumptions made at each point of connection.

In going from the intermediate conclusion to the conclusion, we are assuming that the painting being almost certainly a van Gogh is sufficient to conclude that the price of the painting, about which we have been given no information, is a bargain. We all know that van Gogh paintings are some of the most expensive in the world, but imagine if the price in question is $500 million. Is that still a bargain? We don't have enough information to say one way or the other.

There is an even more glaring jump from the original premise to the intermediate conclusion. We need to ask ourselves, are the three common characteristics mentioned (subject matter, brushstrokes, color combinations) enough to prove the painting to be a van Gogh? What else needs to be considered?

For one, surely, there are better, more specific ways to authenticate a van Gogh. It is the 21st century after all.

Furthermore, note that these are very broad and common characteristics—characteristics that paintings from other painters might share. Is it possible that another painter happened to paint similar subjects with broad strokes? Certainly. It's also easily plausible that it's a painting done deliberately in the style of van Gogh. He is an often studied and imitated artist.

The correct answer could have addressed any of these reasons to doubt the connections between the premises, the intermediate conclusion, and the final conclusion, and it happened to address a broad one: the evidence is simply not sufficient to prove that van Gogh painted the picture—someone else could have painted the picture in a style similar to his.

The correct answer is (D): provides no evidence that the painting is more likely to be an uncataloged van Gogh than to be a painting by someone else who painted that particular subject in van Gogh's style.

You might be asking at this point, “But wait…Doesn't answer (D) bring in outside information? How is it not out of scope?”

One of the best things you can do during the course of your studies is to develop solid instincts about which answers are “in scope” and which are “out of scope.” In this case, answer (D), the correct answer, brings up other artists, and perhaps this made the answer less attractive to you at first.

Many test-takers rely on matching up key words in the answer choices with those in the argument to determine what is “in scope.” While this might be helpful some of the time, it is not a reliable strategy. In fact, it will often be true that answers that can be considered out of scope will involve many key words that match those in the argument, and answers that will be in scope, like answer (D) here, will bring up elements that are not in the original argument.

The decision is not how the answer relates to the argument as a whole; for Assumption Family questions, the decision of in-scope and out-of-scope has to do with the relationship between the answer choice and the core. The answer is in-scope if you can see some relation between that answer and the core. It is out-of-scope if you can't. In this case, we can see that it is relevant to consider other painters when deciding whether or not van Gogh painted the picture.

Finding the core and evaluating the flaw or flaws in the core will set us up not only to find the right answer but also to quickly eliminate out-of-scope wrong answers. Very often, wrong answers are built using terms and ideas from other parts of the argument. If you don't know where to focus, these answer choices will seem much more attractive. If you are zeroed in on the core, you can more easily make quick eliminations.

Let's evaluate the incorrect answers. For Identify the Flaw questions, the majority of incorrect answers will have no direct connection to the core, or to the flaws that the argument is designed for us to anticipate. To illustrate the point, let's compare the answer choices to the core of the van Gogh argument:

(A) ignores the fact that there can be general agreement that something is the case without its being the case

There is no general agreement being used as a premise, nor is general agreement something that is required in order for the conclusion to be true.

(B) neglects to cite expert authority to substantiate the claim about the subject matter of the painting

We have no indication that expert authority is required for the argument to be sound, let alone specifically required for validating a match of subject matter. Don't be tempted into thinking that we've got to justify the premise!

Profit is not relevant to the core.

(E) attempts to establish a particular conclusion because doing so is in the reasoner's self interest rather than because of any genuine concern for the truth of the matter

If you are the suspicious type, this answer might be attractive to you (the owner just wants to turn a buck!). Because of this, answer (E) is probably the most attractive of the wrong choices. But we've been given no indication at all that the owner is unscrupulous, and it's not our task to figure out whom we should be suspicious of. Answer choice (E) may represent a tempting ulterior motive, but it does not represent a flaw in the reasoning used in the argument core.

Let's look at one more example for which it can be useful to think about “what else.” Take 1:20 to try this question on your own first. Make sure to read like a debater and try to identify at least one flaw before moving on to the answer choices.

PT33, S3, Q15

Scientists hoping to understand and eventually reverse damage to the fragile ozone layer in the Earth's upper atmosphere used a spacecraft to conduct crucial experiments. These experiments drew criticism from a group of environmentalists who observed that a single trip by the spacecraft did as much harm to the ozone layer as a year's pollution by the average factory, and that since the latter was unjustifiable so must be the former.

The reasoning in the environmentalists’ criticism is questionable because it

(A) treats as similar two cases that are different in a critical respect

(B) justifies a generalization on the basis of a single instance

(D) attempts to compare two quantities that are not comparable in any way

(E) presupposes that experiments always do harm to their subjects

We can represent the core of the environmentalists’ argument as follows:

Harm spacecraft does to ozone is equal to that a factory does in a year.
+
Harm from factory is unjustifiable.

Harm spacecraft does to ozone unjustifiable.

To evaluate this, let's read like a debater. Think up a reason that the harm done by the spacecraft is justifiable. Yes, the spacecraft trip damaged the ozone layer, but…perhaps the experiments led to important breakthroughs and to methods for repairing the ozone layer. Right! Just because something causes some harm doesn't mean it's harmful overall—there are plenty of medicines that we consider beneficial regardless of their nasty side-effects.

The point is this: in evaluating whether something is justifiable or not, we must consider the benefits as well as the harms. This is the flaw in the argument. The author hasn't considered the relative differences in the benefits that a spacecraft mission—to study the ozone—and a factory might have in determining whether the action is justified. The author has come to a conclusion based on an incomplete equation.

While we might expect the correct answer to say something like “ignores the potential environmental benefits of conducting the experiments,” the answer describes the flaw in a more abstract manner—another confirmation that we should work from wrong-to-right and not simply match words.

The correct answer is (A): treats as similar two cases that are different in a critical respect.

The author compares the harm from factories with harm caused by a spacecraft mission without considering the relative benefits, and one benefit specifically—the mission can give us information valuable in healing the ozone, whereas the harm a factory does can't benefit the ozone in any obvious way.

Let's take a quick look at the incorrect answers, and relate them to the core:

Harm spacecraft does to ozone is equal to that a factory does in a year.
+
Harm from factory is unjustifiable.

Harm spacecraft does to ozone unjustifiable.

(B) justifies a generalization on the basis of a single instance

It's not clear what the generalization is, nor is it clear what the single instance is. This answer isn't relevant to this argument.

This is a tempting answer, but it does not directly address the issue of whether the harm is justifiable or not. Distinguishing between reversing and preventing harmful effects may be helpful in comparing two approaches to fighting ozone harm, but such a distinction would not prove or disprove that the harm the spacecraft does is justifiable.

(D) attempts to compare two quantities that are not comparable in any way

It is true the argument compares the pollution caused by two elements (spacecraft and factories) that otherwise don't naturally match up together, but the argument does not compare two quantities that are not comparable. Furthermore, “in any way” is too extreme.

(E) presupposes that experiments always do harm to their subjects

Doing harm to subjects is not relevant to the core.

To review, we know that for all Identify the Flaw questions there is going to be something wrong with the reasoning in the core of the argument. Therefore, we want to read with as critical an eye as possible. Look at the flaw from two perspectives—in terms of a mismatch, and in terms of what else needs to be considered—to better understand the issues in an argument in a clear and specific way.

Keep in mind that even though flaws can often more easily be seen from one perspective or another, our two perspectives—what is the mismatch and what else needs to be considered—are not meant to be separate or opposite. In fact, there is great overlap between the two.

Consider two simple arguments we've discussed in depth:

Cats are friendlier than dogs.

Cats make for the best pets.

Janice is strong.

Janice is athletic.

Note that in both cases, there are flaws that can be considered from either perspective. It is correct to say that being a friendly pet and being the best pet are not the same thing. It is also correct to say that the author has failed to consider other pet types. The same dual perspective holds true for the second argument. It is correct to say that strong and athletic are not the same thing. It is also correct to say that being strong is only one part of being athletic, and that other issues need to be considered.

Your goal is not to categorize the flaw as fitting into one category or another. Your goal is to use both perspectives to understand the flaw as clearly as you can.

Causation Flaws

The most common reasoning flaws you'll see in Identify the Flaw questions are those that involve causation. Any claim of one element having a direct impact on another can be considered a claim of causation. Here are a few examples of causation claims:

“The success of the research project was due in part to the amount of money invested.”
“The dishwashing soap is what removed the stain.”
“Eating blueberries lowers one's chances of developing heart disease.”

In each of the above examples, the impact that one element or idea has on another is stated directly. Note that on the LSAT, issues of causation will appear in two main ways—they will either be stated explicitly in the conclusion, or they will be implicitly involved in the connection that is assumed between the premises to the conclusion.

Let's use two simple arguments to clarify the difference:

Explicit:	Implicit:
“Ted didn't sleep well the night before the exam and performed poorly. Therefore, it's clear that his lack of sleep had a direct impact on his performance.”	“Ted didn't sleep well the night before the exam and performed poorly. He would have performed better if he could have gotten more sleep.”

The arguments are very similar, and they both involve a claim about causation. Notice in the first example that the causation claim is stated explicitly: “His lack of sleep had a direct impact….”

In the second example, that claim is never explicitly stated. Rather, it is implied. The author is making an unstated assumption in using the evidence to validate the conclusion—he is assuming that lack of sleep must have had some impact on Ted's performance.

In either situation, you should be very suspicious of the causation reasoning. For Identify the Flaw questions, almost all claims of causation that appear either explicitly in the conclusion or implicitly in the assumptions made by the author can and should be considered faulty. In these cases, the evidence provided will not be sufficient to validate the claim of causation.

This is a very important point to remember because the writers of the exam will do their best to make these claims of causation seem sound. In fact, some of the most challenging questions involving causation are challenging because the argument seems so very reasonable. Therefore, go in knowing that you should be suspicious! Consider the following example:

Studies indicate that older antelope are, on average, more cautious than younger antelope. This proves that getting older causes antelope to become more cautious.

This argument seems pretty sound, right? Older antelope are more cautious, so it must be true that getting older is what causes these antelope to become more cautious, right?

When we are given a claim that “A,” in this case getting older, has some direct impact on “B,” in this case becoming more cautious, and the argument seems sound, we can walk through the following checklist:

1. Does the reverse make some sense too? Could B have a direct impact on A? Instead of age having some impact on the amount of caution, could it be that the amount of caution has some impact on getting older? Hmmm. Perhaps it seems unlikely, but see if you can imagine how this might be true and we'll come back to it later.

2. Could it be that something else impacts both A and B? It could be that certain antelope happen to have these two characteristics—older age and more cautiousness—but that these characteristics do not cause, or have any sort of impact, on one another. As an analogy, a certain car may have dents on the exterior, and stains on the interior, but these two characteristics could very well have nothing to do with one another.

3. Could it be that A and B have no impact on one another? It could be that certain antelope happen to have these two characteristics—older age and more cautiousness—but that these characteristics have nothing to do with causing, or having any sort of impact, on one another. As an analogy, state parks in Idaho always have both entrance fees and trees, but while trees and fees may rhyme, they have no causal relationship.

Now, let's go back to the first consideration, “Could B cause A?” Could cautiousness have some direct impact on getting older? It might seem unlikely at first, but consider a herd of antelope, and consider in particular the young in the group. Imagine that some of these young are cautious, and some of them are not. We've all seen nature shows—what might happen to some of these less cautious antelope? Chances are, they are more likely to run into unpleasant circumstances.

We are told that older antelope are, on average, more cautious. Could this be because, on average, more cautious antelope are more likely to survive to an older age? That is, instead of caution increasing with age, it's possible that caution is what allows the antelope to reach old age—it's possible that B causes A.

Keep in mind that our job is not to evaluate which mode of causation is more likely, although having instincts in this regard can certainly be beneficial. It is more important that we simply recognize that the argument is flawed in assuming one path of causation when multiple paths are possible.

If you had trouble seeing some of the alternative paths, that's perfectly understandable. Getting in the habit of asking the above three questions whenever you run into a claim of causation should help you develop better instincts about possible alternative modes of causation. Even when we can't imagine specific alternatives, we'll be in great shape to answer questions. We can feel confident that we can get the question correct as long as we can do two things:

recognize the claim or assumption about causation that the author makes, and
stay open-minded to answer choices that present information about possible alternative modes of causation.

Let's look at an example from earlier to illustrate:

PT39, S4, Q20

Some people believe that good health is due to luck. However, studies from many countries indicate a strong correlation between good health and high educational levels. Thus research supports the view that good health is largely the result of making informed lifestyle choices.

The reasoning in the argument is most vulnerable to criticism on the grounds that the argument

(A) presumes, without providing justification, that only highly educated people make informed lifestyle choices

(B) overlooks the possibility that people who make informed lifestyle choices may nonetheless suffer from inherited diseases

(D) overlooks the possibility that the same thing may causally contribute both to education and to good health

(E) does not acknowledge that some people who fail to make informed lifestyle choices are in good health

Note that the conclusion of the argument is an explicit claim of causation: “Thus research supports the view that good health is largely the result of making informed lifestyle choices.” That is, making informed lifestyle choices has a direct impact on good health.

The evidence in this argument states a correlation between good health and high educational levels. What this means is that there is some statistical evidence that connects the people who happen to have good health and the people who happen to have high educational levels. Statistically speaking, having one changes the percentage chance that you have the other.

However, correlation is never sufficient to prove causation. That is, just because we know that there is a correlation between good health and high educational levels doesn't mean we know that good health is a part of the reason for high educational levels, or vice-versa. Perhaps both are consequences of another characteristic, such as living in a particular location. Or perhaps there is no causal connection, direct or indirect, between the two.

Let's think about our three questions:

Could it be the other way around? Does “B” impact “A”?
Could something else impact both “A” and “B”?
Could it be that “A” and “B” have no direct or indirect impact on one another?

We know that the correct answer will typically address one of these issues.

Could having good health help one make informed lifestyle choices? Maybe, but it is not likely. Regardless, we want to stay open-minded to this possibility when we evaluate the answer choices.
Could something else impact both good health and informed lifestyle choices? Absolutely. As stated before, where a person lives is just one example of something that could have an impact on the likelihood of both.
Could having good health and making informed lifestyle choices have no impact (or, in this case, a small impact) on one another? Yes. We've got a pretty strong conclusion here (“is largely the result”), and not enough evidence to back it up.

The correct answer for this question is (D): overlooks the possibility that the same thing may causally contribute both to education and to good health. The right answer addresses the second of the above concerns. But it was wise to remain open to the idea that it could have been any of them.

Did you notice that this argument also contains a term shift? The argument shifts from “high educational levels” to “informed lifestyle choices.” The correct answer to this Flaw question could have pointed out this mismatch as well.

Let's quickly discuss the incorrect answers:

(A) presumes, without providing justification, that only highly educated people make informed lifestyle choices

This is a tempting answer because it addresses the mismatch between education levels and informed lifestyle decisions. However, the word “only” makes this answer choice too strong. The argument involves generalizations—in shifting terms, the author is assuming a relationship between education and informed lifestyle choices, but not an exclusive one as this answer choice states.

(B) overlooks the possibility that people who make informed lifestyle choices may nonetheless suffer from inherited diseases

It may be true that they suffer from inherited diseases, but we've been given no indication that the rate of inherited diseases is different for the groups—those who don't make informed lifestyle choices may also suffer from inherited diseases, and so it's unclear what impact this information has on the argument being made.

Whether the choices are available to everyone is not mentioned in the argument and has no direct bearing on it.

(E) does not acknowledge that some people who fail to make informed lifestyle choices are in good health

The author does not conclude that only people who make informed lifestyle choices are healthy. The conclusion is that such choices are the major factor in good health.

Let's take a look at another question that involves an explicit claim of causation. Try to anticipate potential answers, and see if one of the answer choices matches your prediction.

PT22, S2, Q10

The only motives that influence all human actions arise from self-interest. It is clear, therefore, that self-interest is the chief influence on human action.

The reasoning in the argument is fallacious because the argument

(A) denies that an observation that a trait is common to all the events in a pattern can contribute to a causal explanation of the pattern

(B) takes the occurrence of one particular influence on a pattern or class of events as showing that its influence outweighs any other influence on those events

(C) concludes that a characteristic of a pattern or class of events at one time is characteristic of similar patterns or classes of events at all times

(D) concludes that, because an influence is the paramount influence on a particular pattern or class of events, that influence is the only influence on that pattern or class of events

(E) undermines its own premise that a particular attribute is present in all instances of a certain pattern or class of events

In this argument, the author makes a very strong claim of causation—self-interest is the chief influence on human action. The evidence might seem very strong—self-interest is the only motive that influences all human actions!

But does that mean it's the chief influence?

Well, fortunately, we can use our familiarity with the exam to our advantage here. We know there's something wrong with the argument. So, what we're thinking is:

“Is it possible that self-interest is a part of every action, but not the chief influence?”

Absolutely. Perhaps, looking at the argument from this critical perspective, it might be easier to see how one characteristic or element may always be present in another, but not the chief influence. Imagine a dinner where the only thing that is common to all dishes is salt and pepper. Would we say that salt and pepper are the chief flavors in the meal? Not necessarily. Even though self-interest is always there, perhaps something else, such as a desire to have a positive impact on the lives of others, has a much stronger influence on our actions.

The flaw in the argument is that the author assumes that just because self-interest is a part of every action, it must be the chief influence in every action.

Answer choice (B), the correct answer, addresses this issue: takes the occurrence of one particular influence on a pattern or class of events as showing that its influence outweighs any other influence on those events.

The answer is worded in a challenging way, but it essentially gives us the information we expect. The argument is flawed in that it assumes that how often a characteristic appears translates to how strong an influence that characteristic is.

Let's break down the incorrect answer choices:

(A) denies that an observation that a trait is common to all the events in a pattern can contribute to a causal explanation of the pattern

This answer choice is very attractive because it can easily be misread, but notice that what it is saying is that the author denies that self-interest can have an influence—this answer choice is actually the opposite of what we are looking for.

(C) concludes that a characteristic of a pattern or class of events at one time is characteristic of similar patterns or classes of events at all times

This is not what is happening in the argument. The author is not concluding that a characteristic that appeared once appears always.

(D) concludes that, because an influence is the paramount influence on a particular pattern or class of events, that influence is the only influence on that pattern or class of events

This answer choice is about whether a chief influence is necessarily the only influence. We are interested in whether the sole common influence is necessarily the chief influence.

(E) undermines its own premise that a particular attribute is present in all instances of a certain pattern or class of events

The premise is not undermined, and so we can eliminate this choice.

Let's take a look at another problem. Here, no claim of causation is stated explicitly, but the argument does have a causation issue. See if you can spot it before looking at the answer choices:

PT14, S4, Q18

According to a government official involved in overseeing airplane safety during the last year, over 75 percent of the voice recorder tapes taken from small airplanes involved in relatively minor accidents record the whistling of the pilot during the fifteen minutes immediately preceding the accident. Even such minor accidents pose some safety risk. Therefore, if passengers hear the pilot start to whistle they should take safety precautions, whether instructed by the pilot to do so or not.

The argument is most vulnerable to criticism on the grounds that it

(A) accepts the reliability of the cited statistics on the authority of an unidentified government official

(B) ignores the fact that in nearly one quarter of these accidents following the recommendation would not have improved passengers’ safety

(D) provides no information about the percentage of all small airplane flights during which the pilot whistles at some time during that flight

(E) fails to specify the percentage of all small airplane flights that involve relatively minor accidents

For the previous two questions, we looked at arguments that have an explicit claim of causation—more specifically, arguments with causation conclusions that we are meant to evaluate and ultimately find fault with.

However, sometimes the causation flaw is not explicit—it exists in a faulty, unstated assumption that the author has made. That's the case in this problem. Notice that the conclusion does not contain a claim of causation. However, the author is assuming a causal relationship in reaching his conclusion.

To illustrate, let's separate out the argument core:

In over 75% of minor accidents, pilot of small plane recorded whistling

If passenger hears whistling, should take safety precautions

The conclusion, in this case, is a suggestion of what one should do. If a passenger hears whistling, he or she should take safety precautions.

Why? How did the author reach this conclusion? What was his reasoning? What did he assume, or, more specifically, how did he interpret the evidence?

In reaching the conclusion that the passenger should take safety precautions, the author is implying that the whistling is indicative of a greater likelihood of danger—in other words, that whistling has some impact on the chances of being in an accident.

Is this assumption about causation sound? Let's run it through our questions:

Could it be reversed? Could the likelihood of being in an accident make one whistle more? Not likely.
Could there be some other influence on both? Perhaps boredom makes one whistle, and makes one more likely to get in accidents, but that's a stretch.
Could it be that there is no connection between the two? Absolutely! It can just be a coincidence, or there could be some alternative explanation. Imagine, for instance, that over 75% of pilots just happen to always whistle while they fly. If that's the case, the author couldn't make the case that hearing whistling increases the likelihood of being in an accident.

The correct answer choice, (D), addresses this issue: provides no information about the percentage of all small airplane flights during which the pilot whistles at some time during that flight.

Without this information, we can't prove that whistling represents an increased likelihood of getting in an accident.

Let's take a look at the incorrect answers:

(A) accepts the reliability of the cited statistics on the authority of an unidentified government official

Notice that this answer choice puts into question the validity of our premise. That's not our job here. This does not represent a reasoning flaw, and we are looking for reasoning flaws only.

(B) ignores the fact that in nearly one quarter of these accidents following the recommendation would not have improved passengers’ safety

The argument is not about what happens after passengers take the recommended safety precautions, but rather whether they should take those precautions when they hear whistling. Furthermore, is a recommendation unwarranted if it helps improve safety only 75% of the time?

This answer choice is not directly relevant to the reasoning in the argument.

(E) fails to specify the percentage of all small airplane flights that involve relatively minor accidents

This is a tempting answer, but ultimately out of scope. This answer choice is about the percentage of small airplane flights that involve minor accidents. Whether this percentage is 0.1% or 90%, it does not impact the relationship between whistling and the likelihood of getting in an accident.

Let's finish by revisiting a very unusual example of a problem involving causation:

PT32, S1, Q10

The argument's reasoning is questionable because the argument

(A) infers from the idea that the current geography of modern cities resulted from a particular cause that it could only have resulted from that cause

(B) infers from the idea that the current geography of modern cities resulted from a particular cause that other facets of modern life resulted from that cause

(C) overlooks the fact that many technological innovations other than the personal automobile have had some effect on the way people live

(D) takes for granted that shopping malls do not need large parking lots even given the use of the personal automobile

(E) takes for granted that people ultimately want to live without personal automobiles

In this argument, the causal relationship is not given to us as a conclusion, nor is it something simply assumed by the author. Notice that it is given to us explicitly as a premise. What is the cause? We need to accommodate personal automobiles. What is the effect? A variety of consequences to our living environment. Note that because this cause and effect relationship is given to us as a premise, it is not our job, in this case, to evaluate its validity. Rather, we're meant to evaluate its relationship to the conclusion. Let's take a look at the argument core:

We've designed our geography to accommodate the automobile

Without personal automobiles, our geography would be quite different.

Note that the flaw here is not in assuming the validity of one cause, but rather in seeing that one cause as the only potential cause. The author states that without personal automobiles, the geography of modern cities would be quite different. We know that personal automobiles have led us to a certain type of geography, but are they the only cause that could have led to that geography? Do we know for sure that the geography of modern cities would be different without the personal automobile?

It's possible, but far from certain. We can imagine, perhaps, that we could have evolved to have personal motorcycles, or helicopters, and perhaps the geography would then have resulted in something similar. The flaw in this argument is that the author assumes one cause to be the only cause. Answer choice (A), the correct answer, addresses this issue:

(A) infers from the idea that the current geography of modern cities resulted from a particular cause that it could only have resulted from that cause

We could also look at this through the lens of more formal conditional logic. The premise tells us that cars cities built the way they are, and (A) suggests that NO cars cities NOT built the way they are. It is logically invalid to simply negate both sides of a conditional statement.

Let's take a look at the incorrect answer choices:

(B) infers from the idea that the current geography of modern cities resulted from a particular cause that other facets of modern life resulted from that cause

Other facets of modern life are out of scope.

(C) overlooks the fact that many technological innovations other than the personal automobile have had some effect on the way people live

This gives us other causes, but not causes for a certain geography. Rather, this answer proposes causes for “the way people live.” This would be a good answer if it were worded slightly differently: “overlooks the fact that many technological innovations other than the personal automobile [other causes!] have had some effect on geography.”

(D) takes for granted that shopping malls do not need large parking lots even given the use of the personal automobile

This answer might be attractive if it is misread, but note that it says that the argument takes for granted that shopping malls do not need large parking lots—this is the reverse of what the author discusses, and it is not something that is therefore taken for granted.

(E) takes for granted that people ultimately want to live without personal automobiles

What people want is irrelevant.

The Last Hurdle: Digging Out the Correct Answer

Okay. You've read through the argument, identified the core, and you have a good understanding of the gap or flaw. Are you done with the heavy lifting? For the most part, yes. But the test writers can throw a few more challenges your way. Let's take a look at two ways that the LSAT makes the right answer harder to identify.

To begin, go ahead and try the following two questions. Give yourself 2:40 to 3:00.

PT34, S2, Q3

Restaurant manager: In response to requests from our patrons for vegetarian main dishes, we recently introduced three: an eggplant and zucchini casserole with tomatoes, brown rice with mushrooms, and potatoes baked with cheese. The first two are frequently ordered, but no one orders the potato dish, although it costs less than the other two. Clearly, then, our patrons prefer not to eat potatoes.

Which one of the following is an error of reasoning in the restaurant manager's argument?

(A) concluding that two things that occur at the same time have a common cause

(B) drawing a conclusion that is inconsistent with one premise of the argument

(D) attempting to prove a claim on the basis of evidence that a number of people hold that claim to be true

(E) treating one of several plausible explanations of a phenomenon as the only possible explanation

PT34, S2, Q9

The argument's reasoning is flawed because the argument fails to

(A) distinguish between a study produced for the purposes of the operation of government and a study produced as part of university research

(B) distinguish between a method of investigation and the purpose of an investigation

(D) recognize that two different methods of investigation can yield identical results

(E) recognize that varying economic conditions result in the average workweek changing in length

Challenge #1: Abstract Language

A common way that test writers will try to challenge you is to write the answer choices using generalized, or abstract, language. Most of these answer choices will refer to the underlying reasoning or logic in the argument, and it makes perfect sense that these questions would work this way. After all, you are being tested on your ability to evaluate the underlying reasoning or logic—whether the argument is specifically about potatoes or workweeks is secondary to the test writer.

The great news is that reading for the core, and for structural flaws, in the manner that we've recommended up to this point, is the ideal way to prepare to evaluate an abstract or generalized answer choice.

The bad news is that for many of these questions, it is almost impossible to identify the correct answer if you haven't anticipated it. Most of the answer choices will sound very attractive, and most of the incorrect answers will be answers that could be correct for other arguments. This makes it even more important that you are strong at finding the core, and recognizing common flaws.

Let's look back at one of our two examples to review this issue more in depth:

PT34, S2, Q3

Which one of the following is an error of reasoning in the restaurant manager's argument?

(A) concluding that two things that occur at the same time have a common cause

(B) drawing a conclusion that is inconsistent with one premise of the argument

(D) attempting to prove a claim on the basis of evidence that a number of people hold that claim to be true

(E) treating one of several plausible explanations of a phenomenon as the only possible explanation

We can think of the argument core as follows:

No one orders the potato dish

Our patrons prefer not to eat potatoes

Did you see a flaw when you read the argument initially? The author concludes that the patrons must not prefer potatoes, and the evidence he presents is that no one orders the potato dish. Could there be another reason no one orders the potato dish? Could it be the way that it's prepared? Perhaps the chef thinks capers go well with potatoes, but patrons don't. Perhaps patrons don't like the cheese that is being used. Perhaps people prefer to eat potatoes at home, or only as an accompaniment with meat.

As we've discussed before, it is not necessary for you to take the time to come up with these alternatives. What is important is that you recognize the fault in the reasoning: in using this evidence to validate the conclusion, the author has failed to consider other reasons why patrons don't order the potato dish—the author is thinking of one explanation as the only possible explanation. Answer choice (E), the correct answer, says just that: treating one of several plausible explanations of a phenomenon as the only possible explanation.

Let's discuss the incorrect answers:

(A) concluding that two things that occur at the same time have a common cause

This is a fault that is common to many arguments that appear in Identify the Flaw questions, but this is not a fault of this particular argument. We are not considering two things that happen at the same time. When facing abstract flaw answers, stand your ground. Check that the answer corresponds with the argument. Did the argument really claim that? Did it conclude that? Often these abstract answers refer to claims and conclusions that are simply not in the argument.

(B) drawing a conclusion that is inconsistent with one premise of the argument

This is not representative of a common fault that appears in flaw arguments, and it's not representative of a flaw in this particular argument. Stand your ground! There is no inconsistency between the premise and the conclusion.

This answer choice addresses a more specific flaw. However, it's not a flaw in this argument—there is no confusion of what people say they want and what they choose. The argument is about what people actually want and what they choose.

(D) attempting to prove a claim on the basis of evidence that a number of people hold that claim to be true

We are not told that a number of people believe that the patrons don't like potatoes.

Remember, the key to recognizing correct answers written in an abstract or generalized way is to read for the core and anticipate the reasoning flaw. When stuck between a couple of answer choices, do not simply compare them against one another—this will lead you nowhere! Instead, compare each one to the argument core. Figure out which one best applies to the situation in the argument, and to your understanding of the core.

Here are some more examples of the types of abstract language answers you may face on the exam:

Abstract Answer	In Our Words…	Example
It assumes without warrant that a condition under which a phenomenon is said to occur is the only condition under which that phenomenon occurs.	The argument assumes that one way is the only way.	When businesses on Main Street fail there is commercial space available in the downtown district. Since there is commercial space available in the downtown district, it must be true that businesses on Main Street failed. (Maybe there's another reason space is available.)
Presumes that a condition necessary for an outcome is sufficient for that outcome.	The argument assumes that because something is required for an outcome to be true, it guarantees that the outcome will be true.	All NFL linemen weigh over two hundred pounds. Since Ted weighs over two hundred pounds, he must be an NFL lineman. (Not everyone who is over two hundred pounds is an NFL lineman!)
Takes for granted that if one phenomenon co-occurs with another, then the two phenomena must be causally related.	The argument assumes from a correlation that there must be a cause and effect relationship.	Those who have a computer at home have higher incomes on average than those who do not have a computer at home. Thus, having a computer at home leads to a higher income. (Having a computer and a higher income can both be due to other factors, or they can have no causal connection.)
It sets up a dichotomy between alternatives that are not known to be exclusive.	The argument assumes a limited number of possibilities when there could be more.	Since those who love our show already watch it and those who hate our show can't be convinced to watch it, advertising will have no impact on our viewership totals. (What about those who don't have a strong opinion about the show, or have never heard of it?)
Takes for granted that a claim is false based on evidence about the source of the claim rather than any evidence about the claim itself.	The argument makes assumptions about a claim based on the trustworthiness of the source.	Company X claims that its chemical products are completely safe for use at home. This is absurd, since Company X is only concerned with profits and cannot be trusted. (Even if the company is only concerned with profits, the chemical product can still be completely safe.)
Infers from a claim about a single instance of a class that the class must itself possess that characteristic.	The argument assumes that what is true of the parts is true of the whole.	The top scorer in the league is on the Cosmos. Therefore, the Cosmos must have scored more goals than any other team in the league. (One star player does not make a team. What about the other players?)
Too hastily draws a conclusion about what is a matter of fact from evidence that suggests a mere suspicion.	The argument assumes that an opinion is enough to prove the point being made.	John believes that he'll get a “B” in biology this semester, so when his grades are released late next week, his biology grade will in fact report a “B.” (Oh, if only life were that easy! How do we know that John's belief is correct?)
Confuses a relative comparison about one aspect of two different phenomena for an absolute claim about the two phenomena.	The argument assumes that a comparison allows us to infer something absolute.	Training a lion is safe, as anyone can see by simple comparison: those who train sharks are twice as likely to get injured as those who train lions. (Just because something is safer than training sharks does not mean it is actually safe!)

Challenge #2: From Another Point of View

Sometimes you will do everything correctly and come to understand the flaw or flaws perfectly, and you get to the answer choices and still…none of the answers fit what you are looking for! What could be wrong?

Perhaps that didn't happen to you with this next problem, but in any case, let's use it to illustrate the issue:

PT34, S2, Q9

The argument's reasoning is flawed because the argument fails to

(A) distinguish between a study produced for the purposes of the operation of government and a study produced as part of university research

(B) distinguish between a method of investigation and the purpose of an investigation

(D) recognize that two different methods of investigation can yield identical results

(E) recognize that varying economic conditions result in the average workweek changing in length

Here is a simplified version of the core:

the two studies used different methods of investigation

no need to look further for an explanation of the difference in the studies’ results

Do you spot a flaw in the reasoning here? It's actually very similar to that in the previous argument—the author assumes one reason when others could be plausible. In this case, he assumes that because two studies used different methods of investigation, this was the reason for the difference in the studies’ results. Couldn't it be that, though the methods of investigation were different, something else could have caused the difference in the results?

We go in anticipating an answer that addresses this issue. One way it could be worded is that “the author fails to recognize that there could be other reasons for differences in the studies’ results.”

Unfortunately, we don't have that in the answer choices! Let's review what we've got:

The argument's reasoning is flawed because the argument fails to

(A) distinguish between a study produced for the purposes of the operation of government and a study produced as part of university research

We're not told that the governmental study was done for the purposes of the operation of the government, and the author does recognize differences between the two studies discussed.

(B) distinguish between a method of investigation and the purpose of an investigation

The argument doesn't involve the purpose of the investigation. Look back at the argument: there is no gap between method and purpose.

We've been given no claim or evidence that either of the studies was properly or improperly conducted.

(D) recognize that two different methods of investigation can yield identical results

This is in the ballpark of our core, but certainly isn't what we anticipated. Still, it's the best we've seen so far, so let's keep it.

(E) recognize that varying economic conditions result in the average workweek changing in length

The argument is not about the causes of the changes in the workweek, but rather the discrepancy in the results reported in two different studies about these changes. This answer does not represent issues with this core.

The only viable answer is (D), but could it be correct? Let's look at it one more time:

(D) [the argument fails to] recognize that two different methods of investigation can yield identical results

What does this mean, exactly? The author doesn't consider the fact that you can use two different methods of investigation and end up with the same result.

Isn't this simply a different perspective on the flaw that we saw initially? The author is mistakenly assuming a one-to-one connection between methods and results. Different methods, the argument assumes, will of course lead to different results. We can think of the flaw as failing to consider other ways to end up with different results, or we can think of the flaw as failing to consider that different methods can yield the same result.

Note that this is very different from an answer that reverses the logic, and it is not equivalent to a conditional logic contrapositive (which will be discussed in great detail in Chapter 8). It is simply a different perspective—a view from another angle—of a flaw that you are expected to anticipate.

Conclusion

Let's review the steps required for success on Identify the Flaw questions:

1. Read for the core. Like assumption questions, Identify the Flaw questions are designed to test your ability to evaluate the relationship between the supporting evidence and the conclusion—so make sure you zero in on the core.

2. See the gap and anticipate the flaw. No matter how sound the core may seem, we know it will contain a flaw. Two considerations that are helpful in identifying flaws are “What is the mismatch?” and “What else has the author failed to consider?”

3. Beware of all claims of causation! Recognize when the author is making an explicit or implicit claim of causation and always consider other causation possibilities.

4. Don't be scared off by challenging correct answers. Be prepared for answers that use abstract language, or present the flaw from a slightly different perspective.

DRILL IT: Identify the Flaw Questions

Give yourself no more than 20 minutes to complete the following problems.

1. PT16, S2, Q10

A fundamental illusion in robotics is the belief that improvements in robots will liberate humanity from “hazardous and demeaning work.” Engineers are designing only those types of robots that can be properly maintained with the least expensive, least skilled human labor possible. Therefore, robots will not eliminate demeaning work—only substitute one type of demeaning work for another.

The reasoning in the argument is most vulnerable to the criticism that it

(A) ignores the consideration that in a competitive business environment some jobs might be eliminated if robots are not used in the manufacturing process

(B) assumes what it sets out to prove, that robots create demeaning work

(D) attempts to support its conclusion by an appeal to the emotion of fear, which is often experienced by people faced with the prospect of losing their jobs to robots

(E) fails to address the possibility that the amount of demeaning work eliminated by robots might be significantly greater than the amount they create

2. PT14, S4, Q20

Monroe, despite his generally poor appetite, thoroughly enjoyed the three meals he ate at the TipTop Restaurant, but, unfortunately, after each meal he became ill. The first time he ate an extra large sausage pizza with a side order of hot peppers; the second time he took full advantage of the all-you-can-eat fried shrimp and hot peppers special; and the third time he had two of TipTop's giant meatball sandwiches with hot peppers. Since the only food all three meals had in common was the hot peppers, Monroe concludes that it is solely due to TipTop's hot peppers that he became ill.

Monroe's reasoning is most vulnerable to which one of the following criticisms?

(A) He draws his conclusion on the basis of too few meals that were consumed at TipTop and that included hot peppers.

(B) He posits a causal relationship without ascertaining that the presumed cause preceded the presumed effect.

(D) He fails to establish that everyone who ate TipTop's hot peppers became ill.

(E) He overlooks the fact that at all three meals he consumed what was, for him, an unusually large quantity of food.

3. PT14, S2, Q10

The government of Penglai, an isolated island, proposed eliminating outdoor advertising except for small signs of standard shape that identify places of business. Some island merchants protested that the law would reduce the overall volume of business in Penglai, pointing to a report done by the government indicating that in every industry the Penglai businesses that used outdoor advertising had a larger market share than those that did not.

Which one of the following describes an error of reasoning in the merchants’ argument?

(A) presupposing that there are no good reasons for restricting the use of outdoor advertising in Penglai

(B) assuming without giving justification that the outdoor advertising increased market share by some means other than by diverting trade from competing businesses

(D) failing to establish whether the marketshare advantage enjoyed by businesses employing outdoor advertising was precisely proportionate to the amount of advertising

(E) disregarding the possibility that the government's proposed restrictions are unconstitutional

4. PT19, S2, Q14

Herbalist: Many of my customers find that their physical coordination improves after drinking juice containing certain herbs. A few doctors assert that the herbs are potentially harmful, but doctors are always trying to maintain a monopoly over medical therapies. So there is no reason not to try my herb juice.

The reasoning in the herbalist's argument is flawed because the argument

(A) attempts to force acceptance of a claim by inducing fear of the consequences of rejecting that claim

(B) bases a conclusion on claims that are inconsistent with each other

(D) relies on evidence presented in terms that presuppose the truth of the claim for which the evidence is offered

(E) mistakes the observation that one thing happens after another for proof that the second thing is the result of the first

5. PT19, S2, Q23

A museum director, in order to finance expensive new acquisitions, discreetly sold some paintings by major artists. All of them were paintings that the director privately considered inferior. Critics roundly condemned the sale, charging that the museum had lost first-rate pieces, thereby violating its duty as a trustee of art for future generations. A few months after being sold by the museum, those paintings were resold, in an otherwise stagnant art market, at two to three times the price paid to the museum. Clearly, these prices settle the issue, since they demonstrate the correctness of the critics’ evaluation.

The reasoning in the argument is vulnerable to the criticism that the argument does which one of the following?

(A) It concludes that a certain opinion is correct on the grounds that it is held by more people than hold the opposing view.

(B) It rejects the judgment of the experts in an area in which there is no better guide to the truth than expert judgment.

(C) It rejects a proven means of accomplishing an objective without offering any alternative means of accomplishing that objective.

(D) It bases a firm conclusion about a state of affairs in the present on somewhat speculative claims about a future state of affairs.

(E) It bases its conclusion on facts that could, in the given situation, have resulted from causes other than those presupposed by the argument.

6. PT19, S4, Q6

Videocassette recorders (VCRs) enable people to watch movies at home on videotape. People who own VCRs go to movie theaters more often than do people who do not own VCRs. Contrary to popular belief, therefore, owning a VCR actually stimulates people to go to movie theaters more often than they otherwise would.

The argument is most vulnerable to criticism on the grounds that it

(A) concludes that a claim must be false because of the mere absence of evidence in its favor

(B) cites, in support of the conclusion, evidence that is inconsistent with other information that is provided

(C) fails to establish that the phenomena interpreted as cause and effect are not both direct effects of some other factor

(D) takes a condition that by itself guarantees the occurrence of a certain phenomenon to be a condition that therefore must be met for that phenomenon to occur

(E) bases a broad claim about the behavior of people in general on a comparison between two groups of people that together include only a small proportion of people overall

7. PT20, S1, Q10

Premiums for automobile accident insurance are often higher for red cars than for cars of other colors. To justify these higher charges, insurance companies claim that, overall, a greater percentage of red cars are involved in accidents than are cars of any other color. If this claim is true, then lives could undoubtedly be saved by banning red cars from the roads altogether.

The reasoning in the argument is flawed because the argument

(A) accepts without question that insurance companies have the right to charge higher premiums for higher-risk clients

(B) fails to consider whether red cars cost the same to repair as cars of other colors

(D) does not specify precisely what percentage of red cars are involved in accidents

(E) makes an unsupported assumption that every automobile accident results in some loss of life

8. PT21, S2, Q5

Irrigation runoff from neighboring farms may well have increased the concentration of phosphorus in the local swamp above previous levels, but the claim that the increase in phosphorus is harming the swamp's native aquatic wildlife is false; the phosphorus concentration in the swamp is actually less than that found in certain kinds of bottled water that some people drink every day.

The argument is vulnerable to criticism on the ground that it

(A) makes exaggerations in formulating the claim against which it argues

(B) bases its conclusion on two contradictory claims

(D) concedes the very point that it argues against

(E) makes a generalization that is unwarranted because the sources of the data on which it is based have not been specified

9. PT33, S3, Q5

The radiation absorbed by someone during an ordinary commercial airline flight is no more dangerous than that received during an ordinary dental X-ray. Since a dental X-ray does negligible harm to a person, we can conclude that the radiation absorbed by members of commercial airline flight crews will also do them negligible harm.

A flaw in the argument is its failure to consider that

(A) there may be many forms of dangerous radiation other than X-rays and the kinds of radiation absorbed by members of commercial airline flight crews

(B) receiving a dental X-ray may mitigate other health risks, whereas flying does not

(D) the longer and the more often one is exposed to radiation, the more radiation one absorbs and the more seriously one is harmed

(E) flying at high altitude involves risks in addition to exposure to minor radiation

10. PT36, S1, Q19

Although it has been suggested that Arton's plays have a strong patriotic flavor, we must recall that, at the time of their composition, her country was in anything but a patriotic mood. Unemployment was high, food was costly, and crime rates were soaring. As a result, the general morale of her nation was at an especially low point. Realizing this, we see clearly that any apparent patriotism in Arton's work must have been intended ironically.

The reasoning above is questionable because it

(A) posits an unstated relationship between unemployment and crime

(B) takes for granted that straightforward patriotism is not possible for a serious writer

(D) overlooks the fact that some citizens prosper in times of high unemployment

(E) confuses irony with a general decline in public morale

Challenge Questions

11. PT36, S3, Q13

While it was once believed that the sort of psychotherapy appropriate for the treatment of neuroses caused by environmental factors is also appropriate for schizophrenia and other psychoses, it is now known that these latter, more serious forms of mental disturbance are best treated by biochemical—that is, medicinal—means. This is conclusive evidence that psychoses, unlike neuroses, have nothing to do with environmental factors but rather are caused by some sort of purely organic condition, such as abnormal brain chemistry or brain malformations.

The argument is vulnerable to criticism because it ignores the possibility that

(A) the organic conditions that result in psychoses can be caused or exacerbated by environmental factors

(B) the symptoms of mental disturbance caused by purely organic factors can be alleviated with medicine

(D) the nature of any medical condition can be inferred from the nature of the treatment that cures that condition

(E) organic factors having little to do with brain chemistry may be at least partially responsible for neuroses

12. PT18, S4, Q9

Brain scans of people exposed to certain neurotoxins reveal brain damage identical to that found in people suffering from Parkinson's disease. This fact shows not only that these neurotoxins cause this type of brain damage, but also that the brain damage itself causes Parkinson's disease. Thus brain scans can be used to determine who is likely to develop Parkinson's disease.

The argument contains which one of the following reasoning errors?

(A) It fails to establish that other methods that can be used to diagnose Parkinson's disease are less accurate than brain scans.

(B) It overestimates the importance of early diagnosis in determining appropriate treatments for people suffering from Parkinson's disease.

(C) It mistakes a correlation between the type of brain damage described and Parkinson's disease for a causal relation between the two.

(D) It assumes that people would want to know as early as possible whether they were likely to develop Parkinson's disease.

(E) It neglects to specify how the information provided by brain scans could be used either in treating Parkinson's disease or in monitoring the progression of the disease.

13. PT16, S3, Q11

A controversial program rewards prison inmates who behave particularly well in prison by giving them the chance to receive free cosmetic plastic surgery performed by medical students. The program is obviously morally questionable, both in its assumptions about what inmates might want and in its use of the prison population to train future surgeons. Putting these moral issues aside, however, the surgery clearly has a powerful rehabilitative effect, as is shown by the fact that, among recipients of the surgery, the proportion who are convicted of new crimes committed after release is only half that for the prison population as a whole.

A flaw in the reasoning of the passage is that it

(A) allows moral issues to be a consideration in presenting evidence about matters of fact

(B) dismisses moral considerations on the grounds that only matters of fact are relevant

(D) asserts that the rehabilitation of criminals is not a moral issue

(E) relies on evidence drawn from a sample that there is reason to believe is unrepresentative

14. PT36, S1, Q10

Cotrell is, at best, able to write magazine articles of average quality. The most compelling pieces of evidence for this are those few of the numerous articles submitted by Cotrell that are superior, since Cotrell, who is incapable of writing an article that is better than average, must obviously have plagiarized superior ones.

The argument is most vulnerable to criticism on which one of the following grounds?

(A) It simply ignores the existence of potential counterevidence.

(B) It generalizes from atypical occurrences.

(D) It relies on the judgment of experts in a matter to which their expertise is irrelevant.

(E) It infers limits on ability from a few isolated lapses in performance.

15. PT16, S2, Q22

Director of personnel: Ms. Tours has formally requested a salary adjustment on the grounds that she was denied merit raises to which she was entitled. Since such grounds provide a possible basis for adjustments, an official response is required. Ms. Tours presents compelling evidence that her job performance has been both excellent in itself and markedly superior to that of others in her department who were awarded merit raises. Her complaint that she was treated unfairly thus appears justified. Nevertheless, her request should be denied. To raise Ms. Tours's salary because of her complaint would jeopardize the integrity of the firm's merit-based reward system by sending the message that employees can get their salaries raised if they just complain enough.

The personnel director's reasoning is most vulnerable to criticism on the grounds that it

(A) fails to consider the possibility that Ms. Tours's complaint could be handled on an unofficial basis

(B) attempts to undermine the persuasiveness of Ms. Tours's evidence by characterizing it as “mere complaining”

(D) ignores the possibility that some of the people who did receive merit increases were not entitled to them

(E) overlooks the implications for the integrity of the firm's merit-based reward system of denying Ms. Tours's request

SOLUTIONS: Identify the Flaw Questions

1. PT16, S2, Q10

The reasoning in the argument is most vulnerable to the criticism that it

(A) ignores the consideration that in a competitive business environment some jobs might be eliminated if robots are not used in the manufacturing process

(B) assumes what it sets out to prove, that robots create demeaning work

(D) attempts to support its conclusion by an appeal to the emotion of fear, which is often experienced by people faced with the prospect of losing their jobs to robots

(E) fails to address the possibility that the amount of demeaning work eliminated by robots might be significantly greater than the amount they create

Answer choice (E) is correct.

The author's final conclusion is that though robots will save humans from doing work that is considered demeaning, this work will be made up for by the demeaning work of maintaining those same robots.

We can think of the core of this argument as follows:

Robots are designed to require least skilled/expensive human labor for maintenance

demeaning human work of maintaining robots = demeaning human work taken over robots

This is a tricky question because in addition to the mismatch between two explicit ideas, “least expensive, least skilled” labor and “demeaning” labor, there is a mismatch between implicit facets of that labor. Let's deal with the explicit mismatch first. Is cheap, unskilled work necessarily demeaning?

A lot of hardworking people might disagree.

Also, because the author is making a strong statement about the interchangeability of two things, a good place to start is to ask if those two things are truly comparable; if one thing truly substitutes for another in a society, then many aspects of those things must “line up.” (For example, personal jets have the same function as personal automobiles do—to transport people from one place to another. Has the personal jet taken over the role of the personal automobile in our society? No, because not everyone can afford a personal jet! The vehicles’ individual functions may be similar, but their roles in society are quite different.) Will the old work taken away be cancelled out by the new work created? There are several ways in which these two types of labor may not be interchangeable—if one comes to mind right away, great. If not, just keep in mind that the correct answer could deal with the nature of that comparison.

Let's take a look at the answer choices:

(A) is out of scope. the author is making a sweeping statement about the nature of human labor in our society, not just about “some jobs” in the “manufacturing process.” While jobs may or may not be lost, this is not relevant to the author's conclusion.

(B) is tempting, because of the explicit mismatch we mentioned above. But is “robots create demeaning work” the argument's conclusion? No, the main point is that the work taken away will be cancelled out by the work added.

(C) has no bearing on the conclusion. Whether the engineers consider a type of work demeaning does not tell us whether the work is demeaning; it also does not relate to the “work taken away = work added” conclusion. Finally, the work that engineering designers do may not be the work that robots would do.

(D) is both factually incorrect and has no bearing on the conclusion. There is no direct appeal to people afraid of losing their jobs and, even if there were, it would not address the “work taken away = work added” conclusion.

This leaves us with answer (E), which is similar to the implicit “comparableness of work” issue we predicted. If the type of work is comparable (“demeaning”), then we also need the quantity of that work to be comparable for the conclusion to hold true. If robots take over 1,000,000 demeaning jobs but require 1 person to do unskilled maintenance, then the “work taken away = work added” conclusion does not hold.

Therefore, answer (E) is correct.

2. PT14, S4, Q20

Monroe's reasoning is most vulnerable to which one of the following criticisms?

(A) He draws his conclusion on the basis of too few meals that were consumed at TipTop and that included hot peppers.

(B) He posits a causal relationship without ascertaining that the presumed cause preceded the presumed effect.

(D) He fails to establish that everyone who ate TipTop's hot peppers became ill.

(E) He overlooks the fact that at all three meals he consumed what was, for him, an unusually large quantity of food.

Answer choice (E) is correct.

Monroe is proposing that one event is “due to” something else—in other words, the first event is caused by the second. Anytime we see a causation argument, we can think through our causation checklist:

1. Does the reverse make some sense too? Could B have a direct impact on A? Could the fact that he ate peppers have been caused by his later illness? Probably not.

2. Could it be that something else impacts both A and B? Could some condition that predisposed him to order peppers also be responsible for making him ill? Possible, but unlikely.

3. Could it be that A and B have no impact on one another? Could the fact that he had peppers and got ill be unrelated? Absolutely! There were no meals that he ate that did not involve peppers. What if something completely unrelated made him sick? The temperature of the room? The air freshener? Notice that the argument mentions that Monroe generally has a “poor appetite.” But the quantity of food he finished at TipTop is pretty staggering—an extra large pizza, all-you-can-eat shrimp, and a giant meatball sub. What if eating all those jumbo meals—not the side of peppers he had with every meal—made him sick?

(A) is tempting because “small sample size” can be a flaw of an experiment. However, this choice does not account for any meals that did not contain hot peppers. Even if he had 100 TipTop meals that included hot peppers, this would not address the concern we identified above.

(B) is factually inaccurate (although it may be hard to tell because of the deliberately abstract language). Stand your ground! The author does posit (“put forth”) a causal relationship, but we know that the presumed cause (eating peppers) happened before the presumed effect (getting sick).

(D) has no bearing on the argument. We don't care if everyone became ill, only if Monroe did (and what the cause of that illness was).

(E) is exactly what we predicted above. Even if we had missed the size of his meals on our first read, examining choice (E) reveals that this choice gives us another possible explanation for why he both ate peppers and got ill after his meals.

3. PT14, S2, Q10

Which one of the following describes an error of reasoning in the merchants’ argument?

(A) presupposing that there are no good reasons for restricting the use of outdoor advertising in Penglai

(B) assuming without giving justification that the outdoor advertising increased market share by some means other than by diverting trade from competing businesses

(D) failing to establish whether the marketshare advantage enjoyed by businesses employing outdoor advertising was precisely proportionate to the amount of advertising

(E) disregarding the possibility that the government's proposed restrictions are unconstitutional

Answer choice (B) is correct.

While causality is not explicitly mentioned here, the merchants’ objection to the proposed law is based on what they perceive to be a causal link between signage size and business volume: bigger signage has a direct impact on bigger market share. This is not necessarily a true causal relationship—what if, for example, companies with bigger market share are the only ones who can afford bigger signs? The flaw might deal with this correlation/causation gap.

Also, always look carefully at the wording of the conclusion: “the law would reduce the overall volume of business” on the island. Could there be a language mismatch here? “Market share” is a percentage of overall volume. In other words, a larger market share doesn't necessarily mean more overall business for the island, it just means a bigger piece of the existing pie. The correct answer could also address this mismatch.

Let's go to the answers.

(A) has no bearing on the conclusion. The argument concerns the economic effect of restricting advertising; whether that restriction is justified is irrelevant.

(C) is tempting because the survey's objectivity is not, in fact, addressed. But either way, there is not enough information to say this is an error. If the survey is objective, the flaws we came up with above still hold. If the survey is not objective, we can't make any conclusion (since we don't know what the true results of an objective survey would be). Eliminate it.

(D) is tempting because it is related to the argument's causality/causation claim, which is clearly flawed. However, knowing that sign sizes and market share were proportional would not prove causation; it would only give us more specific information about the correlation. Eliminate.

(E) has no bearing on the conclusion. The argument's scope is restricted to the economic effect of smaller signs; constitutionality is irrelevant.

At first glance, answer (B) may seem too specific to be our flaw, especially if we fixated on the causality flaw first. But upon closer inspection, answer (B) directly addresses the mismatch between the “overall volume” of island business and “market share.” If bigger advertising did in fact increase market share, but did so only by stealing business from other competitors on the island, then the overall volume of business on the island was unaffected. Therefore, the merchants’ argument (even if the problematic causal relationship is true), won't hold water. Answer choice (B) is our answer.

4. PT19, S2, Q14

The reasoning in the herbalist's argument is flawed because the argument

(A) attempts to force acceptance of a claim by inducing fear of the consequences of rejecting that claim

(B) bases a conclusion on claims that are inconsistent with each other

(D) relies on evidence presented in terms that presuppose the truth of the claim for which the evidence is offered

(E) mistakes the observation that one thing happens after another for proof that the second thing is the result of the first

Answer choice (C) is correct.

The conclusion uses very strong wording: “there is no reason not to try my herb juice.” This is an absolute statement, so be suspicious—claims this strong must be backed up with equally strong evidence. Has the argument addressed all possible reasons not to try the herb juice? No way. (Side note: be very careful and picky when dealing with double negatives…the conclusion does not say “you should try my herb juice”—it only says there is no reason not to try it.)

There is also a hidden causal claim here. There is one reason given for not trying the juice (a few doctors claim herb juice might be harmful), and that reason is shot down for the reason that those doctors are trying to maintain a monopoly on therapies. This assumes doctors warn against herb juice only because of self-interest. Is this necessarily true? No; the two things could be unrelated—if a personal trainer tells you exercise is good because he wants you to train with him, that doesn't necessarily mean that exercise is bad.

Let's look at the answers with these potential flaws in mind.

(A) is factually inaccurate, but may be tempting because of the abstract language. Look at each word specifically—the consequences of rejecting the herb juice are not addressed at all. Eliminate it.

(B) is inaccurate. Are there any claims that are inconsistent with each other? You could argue that the doctors’ warnings and the author's claims are in opposition, but the author isn't using those inconsistencies to prove his argument; he shoots down the doctors’ objections. Eliminate it.

(D) is confusingly written, but inaccurate. Does the evidence provided (“many of my customers find that their physical coordination improves after drinking juice containing herbs”) presuppose the conclusion (“there is no reason not to try my herb juice”) to be true? No. Don't allow deliberately abstract language to overwhelm you—break it down into smaller digestible pieces. Eliminate it.

(E) is tempting because there is no proven causal link between the herb juice and subsequent improved coordination. However, remember that our answer must relate back to the conclusion. Even if the herb juice does not cause improved coordination, does that mean there is no reason not to try it? No. Eliminate it.

That leaves us with answer choice (C), the only choice that addresses a specific reason not to try the juice. Doctors claim that herb juice might be dangerous, and the author rebuts this claim by criticizing doctors in general (by saying they want to maintain a monopoly). But the author never addresses the claim that herb juice might be dangerous—a very clear reason not to try his herb juice. Answer choice (C) is our answer.

5. PT19, S2, Q23

The reasoning in the argument is vulnerable to the criticism that the argument does which one of the following?

(A) It concludes that a certain opinion is correct on the grounds that it is held by more people than hold the opposing view.

(B) It rejects the judgment of the experts in an area in which there is no better guide to the truth than expert judgment.

(C) It rejects a proven means of accomplishing an objective without offering any alternative means of accomplishing that objective.

(D) It bases a firm conclusion about a state of affairs in the present on somewhat speculative claims about a future state of affairs.

(E) It bases its conclusion on facts that could, in the given situation, have resulted from causes other than those presupposed by the argument.

Answer choice (E) is correct.

Here the author's point is that the critics’ evaluation—that the museum had lost first-rate pieces—is correct.

The price is, for her, what settles it—and we know that the price that the paintings resold for was two to three times the price the museum sold them for. We can think of an abbreviated core as follows:

Museum sold artwork at much lower price than that at which artwork was resold

The museum lost first-rate pieces.

There are many gaps to consider here. One, price does not define what a first-rate piece is, especially when it comes to what will be considered first-rate in the future. And we have very little information about whether the price was significant or not. Furthermore, there is an insinuation that the museum undervalued the paintings, but that isn't necessarily true. Perhaps, in the few months between the two sales, other factors caused the price of paintings in general, or paintings of a particular artist, to jump in unexpected ways?

(A) is factually inaccurate. The author never compares the number of people holding any of the views mentioned in the argument.

(B) has no bearing on the conclusion. We have no way of knowing whether there is “no better guide” than expert judgment, and even if we did, who are the experts in this case—the critics or the director? Eliminate it.

(C) is tempting because it addresses the fact that director wanted to purchase new works. However, this answer has no bearing on the critics’ contention, and thus doesn't represent a flaw in the core of this argument.

(D) is tempting because we may have noticed a flaw in the argument about art price stability (high prices at one point does not guarantee high prices in the future). However, the argument does not make claims about the future value of the sold paintings, so this choice is factually inaccurate. Eliminate it.

(E) is correct. It represents the second of the issues we discussed—the change in price could be due to reasons other than the paintings indeed being first-rate.

6. PT19, S4, Q6

The argument is most vulnerable to criticism on the grounds that it

(A) concludes that a claim must be false because of the mere absence of evidence in its favor

(B) cites, in support of the conclusion, evidence that is inconsistent with other information that is provided

(C) fails to establish that the phenomena interpreted as cause and effect are not both direct effects of some other factor

(D) takes a condition that by itself guarantees the occurrence of a certain phenomenon to be a condition that therefore must be met for that phenomenon to occur

(E) bases a broad claim about the behavior of people in general on a comparison between two groups of people that together include only a small proportion of people overall

Answer choice (C) is correct.

The conclusion here is based on an observation about the frequency with which two events occur together (owning a VCR and going to the movies more often)—a classic causality question! Remember our checklist?

1. Does the reverse make some sense too? Could B have a direct impact on A? Could going to the movies more often make people want to own a VCR? Sure—if they like the movies they see maybe they want to watch them again at home.

2. Could it be that something else impacts both A and B? Could these two events have a separate cause? How about a general love of movies? Or higher disposable income?

As soon as we identify a classic causality flaw in this type of question we probably have enough information to proceed to the choices—no reason to predict every possible alternative.

(A) is factually inaccurate. The author presents evidence contrary to the “popular belief” (although whether we agree with that evidence or not is up for debate).

(B) is factually inaccurate. There is nothing inconsistent about the information provided—“popular belief” may be inconsistent with the evidence, but belief is not evidence!

(D) is factually inaccurate. Don't be put off by the abstract language—break it down: is the author saying that people MUST own a VCR in order to go to the movies more often? No; eliminate it.

(E) is tempting because the author does make a claim about general behavior, but the groups of people mentioned are not a small proportion of the overall population. Owning a VCR and not owning a VCR are mutually exclusive—together, the groups of people that fall into those categories make up 100% of the population. Eliminate it.

This leaves us with answer (C), which is exactly one of the flaws we mentioned above (option 2).

7. PT20, S1, Q10

The reasoning in the argument is flawed because the argument

(A) accepts without question that insurance companies have the right to charge higher premiums for higher-risk clients

(B) fails to consider whether red cars cost the same to repair as cars of other colors

(D) does not specify precisely what percentage of red cars are involved in accidents

(E) makes an unsupported assumption that every automobile accident results in some loss of life

Answer choice (C) is correct.

The author's final conclusion is that lives could be saved by banning red cars. The reasoning used is the claim that a greater percentage of red cars are involved in accidents than are cars of any other color. We can think of the core of this argument as follows:

Red color cars have highest likelihood of accident

Lives could be saved by banning red cars.

Notice that in this case, the conclusion doesn't explicitly mention causation. However, causation is implied in the reasoning the author uses to connect evidence to conclusion. Why does the author think lives could be saved by banning red cars? Because he assumes that the car being red has some impact on lives being saved or lost. Remember that in evaluating any claim of causation, it is helpful to think about the potential for the reverse causation and also about no causal relationship at all.

Since the author is assuming that the color being red has an impact on the likelihood of an accident, we want to ask ourselves…

(1) Is it possible that having a higher likelihood of having an accident impacts whether the car is red?

This may seem implausible at first, but it actually makes a lot of sense. Perhaps those who are more inclined to drive in a manner that leads to accidents are more likely to buy red cars.

(2) Is it possible that the color red and the likelihood of being in an accident have no direct impact on one another?

Absolutely. Imagine that the most popular car in the world also happens to be the most dangerous, and it happens to only come in red. In that case, the color of the car could have no causal relation to the likelihood of an accident.

It's not essential that you come up with exact reasons why alternative modes of causation are possible during the course of the actual exam. However, it is critical that you recognize that alternative modes are indeed possible, and that the author is flawed in assuming one particular path of causation.

There is also a mismatch between premise and conclusion having to do with “accidents” versus “deaths.” It's possible certain cars are more likely to lead to accidents, but less likely to lead to fatal accidents. A correct answer could address this flaw as well.

With that in mind, let's take a look at the answer choices:

(A) has no bearing on whether lives will be saved by banning red cars and therefore can be eliminated quickly. Whether insurance companies have this right is not what is at issue.

(B) has no bearing on whether lives will be saved by banning red cars and can be eliminated quickly.

(D) is tempting, in part because such information would be helpful for us in understanding the argument. However, a precise percentage is not required for this argument to hold, and thus this answer doesn't represent a reasoning flaw in this argument.

(E) sounds a lot like the second issue we predicted, and therefore is probably the most tempting incorrect answer.

If we carefully inspect each word in answer (E), the term “every” jumps out at us. Certainly, the author is assuming a connection between accidents and loss of life, but is he assuming every accident results in loss of life? No.

That leaves us with answer (C): “ignores the possibility that drivers who drive recklessly have a preference for red cars.” This sounds exactly like an alternate mode of causation that we predicted.

If we inspect each word in answer (C), nothing jumps out as questionable, and answer (C) makes a lot of sense. In assuming one path of causation, the author is ignoring this other possibility.

Therefore, answer (C) is the correct answer.

8. PT21, S2, Q5

The argument is vulnerable to criticism on the ground that it

(A) makes exaggerations in formulating the claim against which it argues

(B) bases its conclusion on two contradictory claims

(D) concedes the very point that it argues against

(E) makes a generalization that is unwarranted because the sources of the data on which it is based have not been specified

Answer choice (C) is correct.

If the author flat-out declares another claim is true or false, that declaration is often the argument's main conclusion. What is the evidence used to prove that the claim about phosphorus's harmfulness to the swamp's native aquatic life is false? The fact that phosphorus in the swamp is less than phosphorus in certain common kinds of bottled water.

Do you see the mismatch? Whenever two things are compared, make sure those quantities are actually similar. Could water appropriate for human consumption contain higher phosphorus than water appropriate for a swamp's wildlife? Certainly—they are used for completely different functions; one is exclusively for drinking and one is pervasive throughout an entire ecosystem.

Keeping that mismatch in mind, let's look at our choices:

(A) is inaccurate; the claim against which the author argues is simply stated: “increase in phosphorus is harming the swamp's native aquatic wildlife”—there is no exaggeration.

(B) is tempting because there are two contradictory claims presented, but the conclusion of the argument denies one of these claims in favor of the other, rather than basing its conclusion on both. Eliminate it.

(D) is incorrect because ceding a point to the opposition is not a flaw—stating a premise counter to the conclusion, then demonstrating why (despite that counter-premise) the conclusion still holds, is a technique often used in sophisticated arguments. Eliminate it.

(E) is tempting because the sources of the data are indeed not disclosed. However, you cannot dispute the accuracy of information presented in the premises. If the argument says something is a fact, then you must assume it is true (otherwise you could argue with everything simply by saying there isn't documentation for why that thing is true).

That leaves answer (C), which addresses the mismatch in comparability we discussed above. Unlike choice (E), which says we can't prove a conclusion without a specific source, choice (C) directly addresses the fact that the information itself (which we must assume is true because it is presented as true in the argument) may not be relevant to the argument. That's our answer.

9. PT33, S3, Q5

A flaw in the argument is its failure to consider that

(A) there may be many forms of dangerous radiation other than X-rays and the kinds of radiation absorbed by members of commercial airline flight crews

(B) receiving a dental X-ray may mitigate other health risks, whereas flying does not

(D) the longer and the more often one is exposed to radiation, the more radiation one absorbs and the more seriously one is harmed

(E) flying at high altitude involves risks in addition to exposure to minor radiation

Answer choice (D) is correct.

Did you spot the mismatch? There are two things being compared in the conclusion—are they truly comparable? The argument discusses single occurrences of events (an X-ray, a flight) then makes a conclusion about the damage made to multiple people who will undergo multiple occurrences of such events—a mismatch! Smoking a single cigarette may not kill someone, but smoking a single cigarette every waking hour for 20 years might.

(A) is tempting because it seemingly addresses an “alternate consideration” (other types of radiation), but look closely at the first premise. The sentence explicitly states: “The radiation absorbed…,” which covers all kinds of radiation, not just X-ray radiation. Also, the conclusion deals with radiation damage to flight crews, so we only care about the “the kinds of radiation absorbed” by these people. Eliminate it.

(B) has no bearing on the conclusion, because we only care about the risk associated with radiation to flight crews, not other types of risk.

(C) has no bearing on the conclusion. The first premise explicitly compares radiation exposure during an X-ray to radiation exposure during a flight, so higher levels are irrelevant.

(E) has no bearing on the conclusion, because we only care about the risk associated with radiation to flight crews, not other types of risk.

Choice (D) addresses the mismatch between the two quantities we are comparing—if the effect of radiation exposure is cumulative, it is quite possible that a flight crew member, who is repeatedly exposed to radiation, could be harmed more than the average person who only infrequently gets a dental X-ray.

10. PT36, S1, Q19

The reasoning above is questionable because it

(A) posits an unstated relationship between unemployment and crime

(B) takes for granted that straightforward patriotism is not possible for a serious writer

(D) overlooks the fact that some citizens prosper in times of high unemployment

(E) confuses irony with a general decline in public morale

Answer choice (C) is correct.

Why does the author conclude that “clearly…any apparent patriotism in Arton's work must have been intended ironically”? He draws that conclusion from the fact that the country's morale was low, and that it was not in a patriotic mood. There is a big mismatch here—does a citizen of a country necessarily reflect the overall mood of that country? Absolutely not. Let's look at the answers:

(A) has no bearing on the conclusion. Whether unemployment and crime are related has no effect on the core of the argument.

(B) is factually incorrect. The argument never implies this (and that word “not possible” creates a very extreme sentiment!).

(D) is tempting because this choice addresses the possibility that there may be exceptions to the general mood of the country. However, unemployment is only one of many facts cited as evidence for the generally low morale of the country. We must still accept at face value the premise that the “morale of her nation was at an especially low point.” This choice actually has no bearing on our conclusion.

(E) is tempting because it seems to address the mismatch between Arton's mood and the public's mood. However, remember to look at each word with ruthless specificity. Is “irony” itself being confused with low morale? No—the author is making a conclusion about irony based on low morale. Eliminate it.

Choice (C) properly addresses the mismatch between Arton's mood and the country's mood. If she was not attuned to the predominant national attitude, she may have sincerely expressed patriotism, rather than ironically expressing it.

Challenge Questions

11. PT36, S3, Q13

The argument is vulnerable to criticism because it ignores the possibility that

(A) the organic conditions that result in psychoses can be caused or exacerbated by environmental factors

(B) the symptoms of mental disturbance caused by purely organic factors can be alleviated with medicine

(D) the nature of any medical condition can be inferred from the nature of the treatment that cures that condition

(E) organic factors having little to do with brain chemistry may be at least partially responsible for neuroses

Answer choice (A) is correct.

Did you spot the many uses of extreme language in this argument? Let's look at the conclusion first. The phrase “this is conclusive evidence that” lets us know that a conclusion is coming:

“…psychoses, unlike neuroses, have NOTHING to do with environmental factors but rather are caused by some sort of PURELY organic condition.”

What is the evidence for this extreme claim? The argument starts with a counterpremise (“while..”), then lists its star witness—an observation about the best treatment for schizophrenia and other psychoses. The core of the argument looks like this:

schizophrenia and other psychoses are BEST treated by biochemical/medicinal means

psychoses have NO environmental causes and ONLY organic causes

Notice the mismatch in extreme language of the premise and the conclusion—are “best” and “only” the same thing? Just because biochemical treatment is most effective, does that mean no other treatments are effective at all? The alternative treatments may still work, but just not as well as biochemical treatments. And just because a medicinal treatment is effective, does that mean the condition is caused only by biology? No—for example, some people take drugs to alleviate the effects of environmental stress. There are several logic gaps here. There's no need to identify them all—just have a sense of one or two big ones when going to the answers.

(B) has no bearing on the conclusion. The author would probably agree that this choice is true—if psychoses are caused by organic factors, and psychoses are treatable by medicine, then medicine can treat conditions caused by organic factors. But we want to find the flaw in the argument. Eliminate it.

(D) is tempting because the author does make an assumption about the link between the type of treatment and the cause of a condition. But notice that little word “any.” Does the author make an assumption about any condition? No, he only makes one about this particular subgroup. Eliminate it.

(E) has no bearing on the conclusion. The author's claim concerns organic factors—whether they are related to brain chemistry is irrelevant. The phrase “such as” in the conclusion triggers examples of organic causes, not the only types of organic causes. Eliminate it.

Choice (A) addresses the alternate possibility that environmental factors may have an effect on psychoses (either by making the condition worse or by ultimately causing organic conditions that in turn cause psychoses). This is our answer.

12. PT18, S4, Q9

The argument contains which one of the following reasoning errors?

(A) It fails to establish that other methods that can be used to diagnose Parkinson's disease are less accurate than brain scans.

(B) It overestimates the importance of early diagnosis in determining appropriate treatments for people suffering from Parkinson's disease.

(C) It mistakes a correlation between the type of brain damage described and Parkinson's disease for a causal relation between the two.

(D) It assumes that people would want to know as early as possible whether they were likely to develop Parkinson's disease.

(E) It neglects to specify how the information provided by brain scans could be used either in treating Parkinson's disease or in monitoring the progression of the disease.

Answer choice (C) is correct.

The conclusion of this argument claims that a brain scan can help predict Parkinson's. Notice that the word “causes” shows up twice, to link two different correlations (exposure to neurotoxins + Parkinson's-type brain damage and brain damage + Parkinson's). Let's go to our causation checklist:

1. Does the reverse make some sense too? Could B have a direct impact on A?

We have two different causation claims, so check each independently. Could brain damage cause exposure to neurotoxins? Probably not. But could Parkinson's cause brain damage? It's possible.

2. Could it be that something else impacts both A and B?

Could something else impact both exposure to neurotoxins and brain damage? Perhaps not likely but still possible—an explosion could expose someone to both neurotoxins and a physical accident that caused brain damage. Could something else cause both Parkinson's and brain damage? Sure; genetics, another disease, and non-neurotoxin chemicals are some possible candidates.

3. Could it be that A and B have no impact on one another?

Could the neurotoxins and brain damage, or the brain damage and Parkinson's, be completely unrelated? Absolutely. And could both of these relationships be unrelated to each other? Yes—just because a type of brain damage is similar to Parkinson's brain damage, that does not mean the first type is Parkinson's brain damage.

We're not suggesting that you identify every single one of these alternate models. After you identified one possible alternative, it is probably smart to move on to the answers so you can keep a brisk pace under time pressure (but keep that general flaw in mind!).

(A) has no bearing on the conclusion. We don't care about whether this method is more or less accurate than other methods; we only care if it works.

(B) has no bearing on the conclusion. The argument does not discuss treatment.

(D) has no bearing on the argument, which deals with whether brain scans can be used, not whether people will want to use them

(E) has no bearing on the conclusion. The argument does not discuss treatment or monitoring progression.

Choice (C) is the final causation flaw we identified above. Even if you stop before identifying all the flaws, and this flaw is not the specific one you saw first, you can quickly check to see that this statement is true.

13. PT16, S3, Q11

A flaw in the reasoning of the passage is that it

(A) allows moral issues to be a consideration in presenting evidence about matters of fact

(B) dismisses moral considerations on the grounds that only matters of fact are relevant

(D) asserts that the rehabilitation of criminals is not a moral issue

(E) relies on evidence drawn from a sample that there is reason to believe is unrepresentative

Answer choice (E) is correct.

The conclusion that the surgery has “a powerful rehabilitative effect” contains a word that lets us know the author is asserting a causal relationship—“effect.” Does surgery truly cause lower rates of recidivism? Let's go to our checklist:

1. Does the reverse make some sense too? Could B have a direct impact on A?

Could the lower rate of recidivism cause the surgery? Because one event happens later in time than the other, it is unlikely that the later event caused the earlier event (unless you believe in time travel!).

2. Could it be that something else impacts both A and B?

Could something else, however, have caused both surgery and a lower rate of recidivism? Prisoners were “awarded” surgery for good behavior—could this good behavior (or some underlying factor that caused the good behavior) also be responsible for fewer crimes committed after release? Absolutely.

This is a pretty big flaw, and probably enough for us to go on when attacking the answers. Let's look at the choices. Many of them address the morality/controversy of the surgery. A large portion of the argument text deals with the moral implications of the surgery, but notice that the conclusion itself begins with the phrase “putting moral issues aside.” This may help us do some rapid elimination.

(A) has no bearing on the argument. Morality is irrelevant to the primary conclusion of this argument.

(B) is tempting because it directly addresses the fact that the author sweeps morality aside. However, you must deal with the conclusion as given, and the conclusion as given excludes morality.

(D) has no bearing on the argument, and is factually inaccurate. The author never states that rehabilitation is not a moral issue.

This leaves us with answer (E), which may not seem at first to address the causation flaw we found. But take a closer look. How could the sample of prisoners be considered unrepresentative? The group that receives surgery is selected by good behavior, and is therefore not a clear control group to compare against the general population that does not receive the surgery. It is potentially difficult to separate the ultimate cause of the surgery (better behavior in prison) from the ultimate result (better behavior outside of prison). Therefore, choice (E) is our answer.

14. PT36, S1, Q10

The argument is most vulnerable to criticism on which one of the following grounds?

(A) It simply ignores the existence of potential counterevidence.

(B) It generalizes from atypical occurrences.

(D) It relies on the judgment of experts in a matter to which their expertise is irrelevant.

(E) It infers limits on ability from a few isolated lapses in performance.

Answer choice (C) is correct.

Which of the statements is the conclusion? The words “pieces of evidence” and “since” in the second sentence signal that this second sentence contains premises that support something else.

The conclusion, therefore, is the first sentence.

The core of the argument is as follows:

(“evidence”) Cotrell submitted a few superior articles
+
(“since”) Cotrell is incapable of writing a better-than-average article, he must have plagiarized

Cotrell can only write low-to-average quality articles

When we break down the core, it is easier to see that the conclusion merely restates part of the second premise, without additional support.

(A) is factually inaccurate. The argument cites counterevidence (the few superior articles), but attempts to use that counterevidence to support the conclusion. Eliminate it.

(B) is factually inaccurate. There are “atypical occurrences” mentioned (the superior articles), but rather than generalizing from these occurrences, the author attempts to prove the opposite of what they would imply. (A generalization from these occurrences would suggest that Cotrell is able to write superior articles.) Eliminate it.

(D) is factually inaccurate. There are no experts cited in this argument.

(E) is tempting because the first part of the answer (“infers limits on ability”) is correct, but this conclusion is not drawn from isolated lapses in performance, but from isolated superior performances. Read every word of each choice carefully—the test writers may try to sneak something into the end of an otherwise tempting choice that makes it wrong. Eliminate it.

Choice (C) points out the similarity between the conclusion and second premise. The argument assumes the idea that Cotrell writes only low-to-average articles is true, and then uses that idea to prove that the statement “Cotrell writes only low-to-average articles” is true. Answer choice (C) is our answer.

Notice how short the argument and answer choices are—abstract language can make a seemingly simple question very tricky. When dealing with abstract language, which the test writers deliberately employ to confuse test-takers, don't let any small words off the hook—get more specific!

15. PT16, S2, Q22

The personnel director's reasoning is most vulnerable to criticism on the grounds that it

(A) fails to consider the possibility that Ms. Tours's complaint could be handled on an unofficial basis

(B) attempts to undermine the persuasiveness of Ms. Tours's evidence by characterizing it as “mere complaining”

(D) ignores the possibility that some of the people who did receive merit increases were not entitled to them

(E) overlooks the implications for the integrity of the firm's merit-based reward system of denying Ms. Tours's request

Answer choice (E) is correct.

The personnel director concludes that although Ms. Tours was unjustly underpaid, correcting that error would undermine the integrity of the merit system. We can think of the core of the argument in the following way:

Why does the personnel director think the integrity of the merit-based reward system would be compromised? There is a clear mismatch between the wording of the conclusion (“just complain enough”) and the wording of the premises (“compelling evidence” and “justified” complaint). Additionally, if “integrity” of the merit-based reward system is our ultimate goal, wouldn't this goal be threatened by the unfair violation of merit-based rewards in Ms. Tours's case? Let's look at the choices.

(A) has no bearing on the conclusion. Even if Ms. Tours's salary could be raised “unofficially,” the effect on the public perception of the merit-based system would not be improved. In fact, it might be compromised further, since backchannel ways of fixing problems are probably not the best way to demonstrate integrity. Also, the author states that “an official response is required.”

(B) is tempting, because it addresses the mismatch between “compelling evidence” and “just complain enough.” However, does the director actually attempt to undermine the persuasiveness of Ms. Tours’ evidence? No. In fact, he calls the evidence “compelling” and her claim “justified.” Eliminate it.

(C) is tempting because the author does not explicitly state that superior performance is grounds for merit-based increases. However, he does state that Ms. Tours's claim of unfair treatment is justified. The issue is not whether she is entitled to a merit-based increase, but whether the fair awarding of that increase would undermine the system. Eliminate it.

(D) has no bearing on the conclusion. We are only concerned with the effect of Ms. Tours's potential salary increase; we don't care about the salary increases of others.

While choice (E) does not address the more obvious vocabulary mismatch between “just complain enough” and “compelling evidence,” it does address the second concern we identified. If integrity is what we are after, then choosing to uphold something that we know is unfair will undermine that same integrity. This is our answer.