Principle: One should criticize the works or actions of another person only if the criticism will not seriously harm the person criticized and one does so in the hope or expectation of benefiting someone other than oneself.

Application: Jarrett should not have criticized Ostertag’s essay in front of the class, since the defects in it were so obvious that pointing them out benefited no one.

Summary
Jarrett shouldn’t have criticized someone else’s work. Why not? Because according to the principle’s contrapositive, you should never criticize someone else’s work if either (1) the criticism will seriously harm that other person or (2) you don’t expect the criticism to benefit anyone else. And in Jarrett’s case, the criticism didn’t benefit anyone at all.

Missing Connection
Jarrett’s criticism didn’t benefit anyone, but it’s unknown whether he expected his criticism to benefit anyone. And the principle in the stimulus is concerned with whether there’s an expectation of benefiting others. (Whether or not the criticism actually does benefit others is irrelevant.) So we can make the argument valid if we assume that Jarrett didn’t expect his criticism to benefit others.

A
Jarrett knew that the defects in the essay were so obvious that pointing them out would benefit no one.
He wasn’t under the impression that his criticism would benefit anyone. This triggers the contrapositive of the principle: if you don’t have the hope or expectation of benefiting someone else with your criticism, you shouldn’t criticize. Thus Jarrett shouldn’t have criticized.
B
Jarrett’s criticism of the essay would have been to Ostertag’s benefit only if Ostertag had been unaware of the defects in the essay at the time.
The principle is concerned with whether there’s an expectation of benefiting others with one’s criticism. Whether or not the criticism actually does benefit others is irrelevant. (B) is about actual benefits, not expectations, so it has no effect on the argument.
C
Jarrett knew that the criticism might antagonize Ostertag.
Antagonizing is irrelevant to the argument. Any sufficient assumption must show that Jarrett either didn’t expect to benefit anyone with his criticism, or else the criticism seriously harmed Ostertag. “Might antagonize Ostertag” doesn’t trigger either of those conditions.
D
Jarrett hoped to gain prestige by criticizing Ostertag.
This says he hoped to benefit himself, but benefiting oneself is irrelevant to the argument. The principle is concerned with whether there’s an expectation of benefiting others. That Jarrett hoped to benefit himself tells us nothing about whether he also hoped to benefit others.
E
Jarrett did not expect the criticism to be to Ostertag’s benefit.
The principle is concerned with whether one expects to benefit someone other than oneself. (E) merely tells us that Jarrett didn’t expect to benefit Ostertag. To trigger the principle and reach the conclusion, we’d need to know that he didn’t expect to benefit anyone at all.

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Safety consultant: Judged by the number of injuries per licensed vehicle, minivans are the safest vehicles on the road. However, in carefully designed crash tests, minivans show no greater ability to protect their occupants than other vehicles of similar size do. Thus, the reason minivans have such a good safety record is probably not that they are inherently safer than other vehicles, but rather that they are driven primarily by low-risk drivers.

Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that the good safety record of minivans is probably due to their being driven primarily by low-risk drivers. This is based on the fact that in crash tests, minivans showed no greater ability to protect occupants than other vehicles of similar size do.

Notable Assumptions
The author assumes that there’s no other explanation for the better safety record of minivans besides their being driven primarily by low-risk drivers. For example, the author overlooks that other cars that drive near minivans might drive more safely because of the minivan’s presence.

A
When choosing what kind of vehicle to drive, low-risk drivers often select a kind that they know to perform particularly well in crash tests.
It’s not clear whether the average person buying a car knows anything about how minivans perform in crash tests. In any case, minivans don’t perform particularly well compared to other cars, so (A) doesn’t help establish the author’s theory.
B
Judged by the number of accidents per licensed vehicle, minivans are no safer than most other kinds of vehicles are.
If anything, this might weaken the argument, because we would expect that cars driven primarily by low-risk drivers should have fewer accidents per vehicle than other cars. (B) indicates this expectation isn’t met.
C
Minivans tend to carry more passengers at any given time than do most other vehicles.
This helps establish that minivans are the safest vehicles. More passengers per vehicle combined with fewest injuries per vehicle is strong evidence of safety. But it doesn’t reveal anything about the cause of this safety; is it the vehicle itself or the kind of driver?
D
In general, the larger a vehicle is, the greater its ability to protect its occupants.
This suggests part of the reason minivans are safer than other vehicles is their size. If anything, this might weaken by suggesting there are inherent aspects of the minivan that contribute to its safety.
E
Minivans generally have worse braking and emergency handling capabilities than other vehicles of similar size.
This shows the minivan has features that make it inherently less safe than other vehicles. Thus, we have even less reason to believe the minivan’s safety is due to being inherently safer than other cars. This eliminates an alternate explanation for the minivan’s safety.

66 comments

Consumer advocate: There is no doubt that the government is responsible for the increased cost of gasoline, because the government’s policies have significantly increased consumer demand for fuel, and as a result of increasing demand, the price of gasoline has risen steadily.

Summary
The author concludes that the government is responsible for the increase cost of gasoline.
Why?
Because the government’s policies have increased demand for fuel, and as a result of that increase demand, the price of gasoline has increased. (In other words, the government’s policies ultimately caused the price increase.)

Notable Assumptions
Is the government “responsible” for the increased cost, just because it enacted policies that led to that increased cost? Not necessarily — “responsible” in this context means something like fault or blame. But we don’t know that whoever caused the increased price must be at fault/blamed for it.
The author must assume that if the government’s policies caused the increased price of gas, then the government is responsible for the increased price.

A
The government can bear responsibility for that which it indirectly causes.
Necessary, because if it weren’t true — if the government CANNOT bear responsibility for that which it indirectly causes — then the conclusion would not follow from the premises. The premises establish that the government indirectly caused increased gas price. (It’s indirect because there was an intermediate cause — increased demand for fuel.) The author must assume that this indirect cause can result in the government bearing responsibility.
B
The government is responsible for some unforeseen consequences of its policies.
Not necessary, because we don’t know whether any of the consequences of the government’s policies were “unforeseen.” It might be that the government completely foresaw the increased gas price that would result from its policies.
C
Consumer demand for gasoline cannot increase without causing gasoline prices to increase.
Not necessary, because the argument concerns only a single instance in which consumer demand for fuel resulted in increased gas price. The argument concerns responsibility for that particular past phenomenon. But the author doesn’t have to assume anything universal about what consumer demand for gas always leads to.
D
The government has an obligation to ensure that demand for fuel does not increase excessively.
Not necessary, because what the government is obligated to do (what it should or should not do) is a separate issue from what the government is responsible for.
E
If the government pursues policies that do not increase the demand for fuel, gasoline prices tend to remain stable.
Not necessary, because the argument concerns a situation in which government policies did result in increased demand for fuel. What would have happened if the policies did not increase demand for fuel is not something that affects the reasoning of the argument.

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The question stem reads: The flawed pattern of reasoning in which one of the following is most closely parallel to that in the argument above? This is a Parallel Flaw question.

The author states," A species in which mutations frequently occur will develop new evolutionary adaptations in each generation." We can translate this into lawgic to read:

Mutations Frequently Occur -> Develop Evolutionary Adaptations

The author then states the premise and conclusion, "Since species survive dramatic environmental changes only if they develop new evolutionary adaptions (premise), a species in which mutations occur frequently occur will survive drastic environmental changes (conclusion)." Let's translate those into lawgic:

Premise:
Survive Dramatic Environmental Changes -> Develop Evolutionary Adaptations

Conclusion:
Mutations Frequently Occur -> Survive Dramatic Environmental Changes.

We can combine the argument to read:

P1: Mutations Frequently Occur -> Develop Evolutionary Adaptations
P2: Survive Dramatic Environmental Changes -> Develop Evolutionary Adaptations
____________________________________________________________________________
C: Mutations Frequently Occur -> Survive Dramatic Environmental Changes

We can see that the author confused the sufficient and necessary conditions of P2. Evolutionary adaptations are a requirement to survive dramatic environmental changes, but there might be additional requirements, such as having enough food. Let's take the general form of the argument:

A -> C
B -> C
____________
A -> B

By that line of reasoning, we could conclude that all apples (A) are peaches (B) because all apples (A) are fruit (C), and all peaches (B) are fruit (C).

When evaluating an answer choice, we need two sufficient conditions pointing to the same necessary condition. We also need a conclusion that says one of those sufficient conditions is sufficient for the other sufficient condition. Now that we know what we are looking for let's turn to the answer choices.

Answer Choice (A) is incorrect. The first premise says: properly built -> stones support each other. So the next premise needs "stones supporting each other" for the necessary condition. However, we get: sturdy -> properly built. So we can stop reading there.

Answer Choice (B) is incorrect. The first premise says: play before a different audience -> never get the same reaction. So the next premise needs to have "never get the same reaction" for the necessary condition. However, we get: play -> always has a different audience. Like (A), we can stop reading there.

Correct Answer Choice (C) is what we discussed. The first premise says: perfectly honest -> always tell the truth. So the next premise needs "always tell the truth" in the necessary condition. The next premise says: morally upright -> always tell the truth. Ok, so that checks out. The conclusion has to say: perfectly honest -> morally upright, which is exactly what (C) says. So (C) is the right answer.

Answer Choice (D) is incorrect. The first premise says: garden productive -> soil well drained. So the next premise needs "soil well drained" in the necessary condition. However, we get: soil well drained -> good soil. So we can eliminate (D).

Answer Choice (E) is incorrect. The forest premise says: diet healthful -> well balanced. So the next premise needs to have "well balanced" in the necessary condition. However, the next premise says: well-balanced -> includes fruit and vegetables. So we can eliminate (E).


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Scientist: Any theory that is to be taken seriously must affect our perception of the world. Of course, this is not, in itself, enough for a theory to be taken seriously. To see this, one need only consider astrology.

Summarize Argument
The scientist concludes that, while a theory must affect our perception of the world to be taken seriously, that alone isn’t sufficient to take a theory seriously. The scientist points to a supporting example—astrology.

Identify Argument Part
The scientist mentions astrology to provide support for her conclusion, which is that a theory shouldn’t be taken seriously simply because it affects our perception of the world. Evidently, the scientist thinks astrology affects our perception of the world, but shouldn’t be taken seriously for other reasons.

A
an example of a theory that should not be taken seriously because it does not affect our perception of the world
The scientist implies that astrology does affect our perception of the world. She uses it as an example precisely because it affects our perception of the world while nevertheless being a theory that we shouldn’t take seriously.
B
an example of something that should not be considered a theory
The scientist never says astrology shouldn’t be considered a theory. She implies it shouldn’t be taken seriously.
C
an example of a theory that should not be taken seriously despite its affecting our perception of the world
Sure, astrology affects our perception of the world—a necessary condition for a theory to be taken seriously. But the scientist still suggests astrology shouldn’t be taken seriously, presumably for other reasons.
D
an example of a theory that affects our perception of the world, and thus should be taken seriously
The scientist doesn’t believe astrology should be taken seriously, hence why she uses it as an example. Affecting perception is a necessary condition for a theory to be taken seriously, but not a sufficient one according to the argument.
E
an example of a theory that should be taken seriously, even though it does not affect our perception of the world
The scientist doesn’t believe astrology should be taken seriously, though she does believe it affects our perception. This is why she uses astrology as her example.

4 comments

Dogs learn best when they are trained using both voice commands and hand signals. After all, a recent study shows that dogs who were trained using both voice commands and hand signals were twice as likely to obey as were dogs who were trained using only voice commands.

Summarize Argument
Dogs learn best when trained with both voice commands and hand signals. How do we know? In a recent study, dogs trained with both methods were twice as likely to obey instructions compared to dogs trained with only voice commands.

Identify Argument Part
The referenced text is the conclusion. The rest of the argument supports the claim by citing a study.

A
It is an explicit premise of the argument.
The referenced text is a conclusion. Premises, such as the one about the study, support conclusions.
B
It is an implicit assumption of the argument.
If it’s referenced text, it can’t be an implicit assumption! The referenced text is very explicitly the argument’s conclusion.
C
It is a statement of background information offered to help facilitate understanding the issue in the argument.
It’s not background information. It’s a claim that requires support, which the author provides in the form of a recent study.
D
It is a statement that the argument claims is supported by the study.
The referenced text is a supported claim, or in other words, a conclusion. The author supports her claim about dogs learning best with both hand signals and voice commands by citing a recent study. This works!
E
It is an intermediate conclusion that is offered as direct support for the argument’s main conclusion.
There’s only one conclusion in the argument—that dogs learn best with both hand signals and voice commands, which is exactly what the referenced text says.

1 comment

In a study of patients who enrolled at a sleep clinic because of insomnia, those who inhaled the scent of peppermint before going to bed were more likely to have difficulty falling asleep than were patients who inhaled the scent of bitter orange. Since it is known that inhaling bitter orange does not help people fall asleep more easily, this study shows that inhaling the scent of peppermint makes insomnia worse.

Summarize Argument: Phenomenon-Hypothesis

The author hypothesizes that inhaling the scent of peppermint makes insomnia worse. She bases this on the observation that patients with insomnia who inhaled the scent of peppermint before bed were more likely to have difficulty falling asleep than patients who inhaled the scent of bitter orange, which doesn’t help people fall asleep more easily.

Notable Assumptions

The author assumes that inhaling peppermint directly causes difficulty in falling asleep, without considering alternative explanations and other factors.

She also assumes that the only difference between the two groups is the scent they were exposed to, without considering other possible differences that could influence the outcomes.

She also assumes that the study was conducted properly and that the study’s sample is representative of all insomnia sufferers.

A
Several studies have shown that inhaling the scent of peppermint tends to have a relaxing effect on people who do not suffer from insomnia.

The study and the author’s conclusion are only addressing the effects of inhaling the scent of peppermint on people who do suffer from insomnia. So the effects on people who do not suffer from insomnia is irrelevant.

B
The patients who inhaled the scent of bitter orange were, on average, suffering from milder cases of insomnia than were the patients who inhaled the scent of peppermint.

The author assumes that the only difference between the two groups is the scent they inhaled, but (B) shows that those who inhaled bitter orange already had milder insomnia than those who inhaled peppermint. This weakens the conclusion that peppermint worsens insomnia.

C
Because the scents of peppermint and bitter orange are each very distinctive, it was not possible to prevent the patients from knowing that they were undergoing some sort of study of the effects of inhaling various scents.

We don’t know that the patients’ knowledge of the study affected their ability to fall asleep, or why it would have affected one group’s ability but not the other’s. (C) also doesn’t address the author’s conclusion or assumptions.

D
Some of the patients who enrolled in the sleep clinic also had difficulty staying asleep once they fell asleep.

The study and conclusion are only about the effects of the scents on falling asleep. Whether patients stayed asleep is not relevant.

E
Several studies have revealed that in many cases inhaling certain pleasant scents can dramatically affect the degree to which a patient suffers from insomnia.

This could mean that inhaling certain pleasant scents can make insomnia worse or that it can make it better. We also don’t know what qualifies as a “pleasant scent” here. (E) is simply too vague to apply to the author’s conclusion about this specific study.


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