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.

39 comments

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.

51 comments

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).


9 comments