A
more than half of the forest is unnaturally crowded with immature trees
B
mature trees are usually the first to be eaten by tussock moths
C
usually a higher proportion of mature trees than of immature ones are destroyed in forest fires
D
the expected outbreak of tussock moths will almost certainly occur if no attempt is made to counter it
E
there are no completely effective countermeasures against the moth
A
The price of any manufactured good depends more on how fashionable that good is than on the materials it is made from.
B
It is more important for the materials used in the manufacture of clothing to be fashionable than it is for them to be practical.
C
Materials that require relatively little labor in their production tend to be fashionable.
D
The appearance of a manufactured good is the only thing that determines whether it is fashionable.
E
Cultural trends tend to be an important determinant of the prices of materials used in manufacturing.
Question Stem
We're looking at a Necessary Assumption question. The key phrase in the question stem is "assumption required."
Foundational Skills
This question tests your understanding of how to negate conditional statements. What does it mean to say "If A then B is not always true"? It also tests your understanding of how to use an example to support a the negation of a conditional statement. You just need to show one instance of A and not B.
Aside from logic, this argument also tests your ability to distinguish among the concepts of a promise, an obligation, and an ability to perform an action.
Stimulus
The stimulus starts with the conclusion and it is phrased in the negative. The ethicist concludes "The general principle does not always hold true." Okay, what "general principle"? Read between the dashes. "If one ought to do something, then one can do it." That's the general principle and it's a conditional claim. Before you continue, you have to make sure that you know what it means to say "that does not always hold true" to the conditional claim. That's the lesson on negating conditionals. What is the negation of "if A then B?"
The wrong but perhaps tempting answer is "if A then not B" or "if one ought to do something, then one cannot do it."
The right answer is "A does not imply B" or "ought does not imply can." Another way to say that is "An obligation to do something doesn't automatically mean that you are capable of doing the thing." Fully and correctly fleshed out, this seems like a trivially obvious claim. There are so many things that one ought to do, but that doesn't mean that one can do it. "Ought" is a moral claim. "Can" is a physical claim.
But, we still have to support this somewhat obvious conclusion. Reading the next line in the stimulus, you see that the ethicist wants prove her conclusion by "considering an example." A good exercise is to pause here and ask yourself how you would proceed. How would you prove this conclusion with an example? Since the claim is "ought doesn't imply can" or "A does not imply B," you could support this with an example of a situation where there is an "ought" but there is not a "can." A and not B.
That's abstract. Let's bring it down to earth. Can you think of an "ought" situation? A situation where one ought to perform an action? A situation where one has an obligation to do something? How about this: one ought to financially support one's impoverished parents in their old age. That's the A.
Good. Now add to that situation "not B." How about this: but sometimes, one does not have the financial means to do so. There, that's a clean example of an "ought" (a moral obligation) does not automatically create a "can" (a capability).
Having gone through this exercise, let's now look at what example the ethicist provides. She asks us to suppose that someone promises to meet a friend at a certain time but because of an unforeseen traffic jam, it becomes impossible to do so. Remember, this example should be a situation where there is an "ought" (a moral obligation) coupled with a lack of capacity to carry out the obligation (a "cannot"). So is it?
If you think "yes" then you've already subconsciously taken the bait by supplying the missing assumption. The lack of capacity to do something is present given that it is "impossible" to meet the friend at the promised time. But what about the "ought" or the obligation? Is that present? Note the distinction between this example and the one above where it was explicit that "one ought to financially support one's impoverished parents in their old age." Here, there's just a "promise." So we've spotted one necessary assumption bridge, that "a promise creates an obligation." That's required. And stated explicitly, it seems so obvious, which is why it's easy to overlook. We all know that of course a promise creates an obligation, like what kind of jerk are you if that's not one of your operating moral principles in life? But that's not the point. The point of many necessary assumption questions is precisely to identify and make explicit these implicit assumptions, however foundational they might be to leading an ethical life.
I think this much you can anticipate based on the pure form of this argument. You just have to pay attention to the fact that what you were looking for was an obligation yet what the stimulus gave you was a promise. We need the necessary assumption bridge that "a promise creates an obligation."
Answer Choice (A)
Answer choice (A) is incredibly tricky and I think it has the potential to trap students who understand conditional logic and even to some extent anticipated the missing bridge. Remember, we said that what we're looking for is the explicit statement that "a promise creates an obligation." In conditional form, that's "If one promises to do X, then one has an obligation to do X." In the contrapositive, that's "If one does not have an obligation to do X, then one has not promised to do X." Here now we get very close to the trap in (A). (A) says if one "failed to do something" that one "ought to have done," then one "failed to do something" that one "promised to do." Close in appearance, right?
But quite different in meaning. Not having an obligation to do X is not the same as having (and then failing) the obligation to do X. It's contradictory, in fact. I have no obligation to feed my neighbor's dog. That's not the same as my having (and then failing) the obligation to feed my neighbor's dog. Similarly, not promising to do X is not the same as promising (and then failing) to do X. I did not promise to feed my neighbor's cat. That's not the same as my having promised (and then failing) to feed my neighbor's cat.
Answer Choice (B)
Answer choice (B) puts a hard constraint or limit on what could possibly excuse or relieve a person from the obligation to keep a promise. (B) says that there's just one thing that could do it: an unforeseen traffic jam. Okay, but that damages the argument. According to (B) there is no obligation, because the obligation is excused owing to the unforeseen traffic jam. But if the obligation disappears, then the example becomes worthless. We only cared about the example in the first place because it was supposed to create an obligation. That's why (B) is wrong.
As a side note, think about just how absurd the claim in (B) is. I mean, really, nothing else (aside from the unforeseen traffic jam) can excuse me from the obligation to keep a promise? Like if I get into a car accident and have to go to the ER, that won't relieve me of the obligation to keep my promise?
Answer Choice (C)
Answer choice (C) is similar to (A) in that it's giving off the logical appearance of the bridge we anticipated, but in substance, it's all wrong. Remember, the bridge we need is "a promise creates an obligation." (C) tries to bridge "obligation" to "capacity" or "capability." (C) says that an "obligation" to not do X implies a "capability" to not do X. This claim is actually similar to the original general principle that the ethicist is trying to refute, the general principle that an "obligation" to do X implies a "capability" to do X. For example, an obligation to feed the neighbor's dog implies the capability to feed the neighbor's dog. Here, the X is stated in the negative, an obligation to refrain from doing X implies the capability not do X. Is this claim required? No, it's not. We can falsify this claim and leave the original argument unaffected.
Let's falsify this claim. For example, I have an obligation not to reveal to the Nazi officer that I'm hiding a Jewish family in my cellar. I'd like to think that that implies my being capable of not revealing this. But that's just false. Whether I'm capable or not of revealing this depends on so many incidental factors like how good my poker face is, how good the Nazi officer is at detecting lies, how resilient I am to questioning under torture, how committed I am to fulling my obligations. Obligation simply does not imply capability. Okay, (D) is falsified. But then what? We're still where we were with the original argument. There's still that bridge we identified that needs to be built. The argument is not ruined. It's not even affected.
Correct Answer Choice (D)
Answer choice (D) is the correct answer choice for two reasons. First is that it declares the bridge we needed. It says "The obligation created by a promise..." Good. We know this is necessary. Then it goes on to say something else that I did not anticipate. It goes on to say that that obligation (created by a promise) isn't relieved by the fact that the promise now cannot be kept.
Is this necessary? Yes. It didn't occur to me that an obligation once created can be uncreated. I was simply focused on formally bridging "promise" to the creation of an "obligation." But (D) points out something else just as necessary. That the obligation persists even when it becomes impossible to fulfill that obligation. Indeed that is what the ethicist's example requires. Imagine if (D) were false. That is, imagine if impossibility relieved or excused or unmade the obligation. Then the ethicist's argument is ruined. The example would then contain a situation without an obligation. That example would then become useless to support the conclusion.
Answer Choice (E)
Answer choice (E) does not bridge "promise" to "obligation." It merely says that if some "unforeseen" event "interferes" with the keeping of a promise, then that promise should never have been made to begin with. It's an absurd claim, much like (B), but even if we accept this claim, we get no where on the argument. The consequence of this claim, if we accept it, is just that the promise to meet a friend at a certain time should never have been made to begin with. But the promise was made and the question remains whether that promise made created an obligation. (B) is silent.
More to the point, (B) is unnecessary. We can dispense with this absurd claim without damaging the argument. No, (B), that's just not true. You don't have to judge whether a promise should have been made by looking at whether unforeseen events would interfere with the fulfillment of that promise. You might want to look at whether foreseeable events would interfere. That seems reasonable. Like if you can foresee that you'll be attempting to cross downtown rush hour traffic, then you probably shouldn't promise that the trip will only take 10 minutes. But all of this leaves the argument unaffected. Regardless of whether a promise should have been made to begin with, the fact is that a promise was made and we need to know if that promise created an obligation.
Question Stem
We're looking at a Necessary Assumption question. The key phrase in the question stem is "assumption required."
Foundational Skills
This question tests your understanding of how to negate conditional statements. What does it mean to say "If A then B is not always true"? It also tests your understanding of how to use an example to support a the negation of a conditional statement. You just need to show one instance of A and not B.
Aside from logic, this argument also tests your ability to distinguish among the concepts of a promise, an obligation, and an ability to perform an action.
Stimulus
The stimulus starts with the conclusion and it is phrased in the negative. The ethicist concludes "The general principle does not always hold true." Okay, what "general principle"? Read between the dashes. "If one ought to do something, then one can do it." That's the general principle and it's a conditional claim. Before you continue, you have to make sure that you know what it means to say "that does not always hold true" to the conditional claim. That's the lesson on negating conditionals. What is the negation of "if A then B?"
The wrong but perhaps tempting answer is "if A then not B" or "if one ought to do something, then one cannot do it."
The right answer is "A does not imply B" or "ought does not imply can." Another way to say that is "An obligation to do something doesn't automatically mean that you are capable of doing the thing." Fully and correctly fleshed out, this seems like a trivially obvious claim. There are so many things that one ought to do, but that doesn't mean that one can do it. "Ought" is a moral claim. "Can" is a physical claim.
But, we still have to support this somewhat obvious conclusion. Reading the next line in the stimulus, you see that the ethicist wants prove her conclusion by "considering an example." A good exercise is to pause here and ask yourself how you would proceed. How would you prove this conclusion with an example? Since the claim is "ought doesn't imply can" or "A does not imply B," you could support this with an example of a situation where there is an "ought" but there is not a "can." A and not B.
That's abstract. Let's bring it down to earth. Can you think of an "ought" situation? A situation where one ought to perform an action? A situation where one has an obligation to do something? How about this: one ought to financially support one's impoverished parents in their old age. That's the A.
Good. Now add to that situation "not B." How about this: but sometimes, one does not have the financial means to do so. There, that's a clean example of an "ought" (a moral obligation) does not automatically create a "can" (a capability).
Having gone through this exercise, let's now look at what example the ethicist provides. She asks us to suppose that someone promises to meet a friend at a certain time but because of an unforeseen traffic jam, it becomes impossible to do so. Remember, this example should be a situation where there is an "ought" (a moral obligation) coupled with a lack of capacity to carry out the obligation (a "cannot"). So is it?
If you think "yes" then you've already subconsciously taken the bait by supplying the missing assumption. The lack of capacity to do something is present given that it is "impossible" to meet the friend at the promised time. But what about the "ought" or the obligation? Is that present? Note the distinction between this example and the one above where it was explicit that "one ought to financially support one's impoverished parents in their old age." Here, there's just a "promise." So we've spotted one necessary assumption bridge, that "a promise creates an obligation." That's required. And stated explicitly, it seems so obvious, which is why it's easy to overlook. We all know that of course a promise creates an obligation, like what kind of jerk are you if that's not one of your operating moral principles in life? But that's not the point. The point of many necessary assumption questions is precisely to identify and make explicit these implicit assumptions, however foundational they might be to leading an ethical life.
I think this much you can anticipate based on the pure form of this argument. You just have to pay attention to the fact that what you were looking for was an obligation yet what the stimulus gave you was a promise. We need the necessary assumption bridge that "a promise creates an obligation."
Answer Choice (A)
Answer choice (A) is incredibly tricky and I think it has the potential to trap students who understand conditional logic and even to some extent anticipated the missing bridge. Remember, we said that what we're looking for is the explicit statement that "a promise creates an obligation." In conditional form, that's "If one promises to do X, then one has an obligation to do X." In the contrapositive, that's "If one does not have an obligation to do X, then one has not promised to do X." Here now we get very close to the trap in (A). (A) says if one "failed to do something" that one "ought to have done," then one "failed to do something" that one "promised to do." Close in appearance, right?
But quite different in meaning. Not having an obligation to do X is not the same as having (and then failing) the obligation to do X. It's contradictory, in fact. I have no obligation to feed my neighbor's dog. That's not the same as my having (and then failing) the obligation to feed my neighbor's dog. Similarly, not promising to do X is not the same as promising (and then failing) to do X. I did not promise to feed my neighbor's cat. That's not the same as my having promised (and then failing) to feed my neighbor's cat.
Answer Choice (B)
Answer choice (B) puts a hard constraint or limit on what could possibly excuse or relieve a person from the obligation to keep a promise. (B) says that there's just one thing that could do it: an unforeseen traffic jam. Okay, but that damages the argument. According to (B) there is no obligation, because the obligation is excused owing to the unforeseen traffic jam. But if the obligation disappears, then the example becomes worthless. We only cared about the example in the first place because it was supposed to create an obligation. That's why (B) is wrong.
As a side note, think about just how absurd the claim in (B) is. I mean, really, nothing else (aside from the unforeseen traffic jam) can excuse me from the obligation to keep a promise? Like if I get into a car accident and have to go to the ER, that won't relieve me of the obligation to keep my promise?
Answer Choice (C)
Answer choice (C) is similar to (A) in that it's giving off the logical appearance of the bridge we anticipated, but in substance, it's all wrong. Remember, the bridge we need is "a promise creates an obligation." (C) tries to bridge "obligation" to "capacity" or "capability." (C) says that an "obligation" to not do X implies a "capability" to not do X. This claim is actually similar to the original general principle that the ethicist is trying to refute, the general principle that an "obligation" to do X implies a "capability" to do X. For example, an obligation to feed the neighbor's dog implies the capability to feed the neighbor's dog. Here, the X is stated in the negative, an obligation to refrain from doing X implies the capability not do X. Is this claim required? No, it's not. We can falsify this claim and leave the original argument unaffected.
Let's falsify this claim. For example, I have an obligation not to reveal to the Nazi officer that I'm hiding a Jewish family in my cellar. I'd like to think that that implies my being capable of not revealing this. But that's just false. Whether I'm capable or not of revealing this depends on so many incidental factors like how good my poker face is, how good the Nazi officer is at detecting lies, how resilient I am to questioning under torture, how committed I am to fulling my obligations. Obligation simply does not imply capability. Okay, (C) is falsified. But then what? We're still where we were with the original argument. There's still that bridge we identified that needs to be built. The argument is not ruined. It's not even affected.
Correct Answer Choice (D)
Answer choice (D) is the correct answer choice for two reasons. First is that it declares the bridge we needed. It says "The obligation created by a promise..." Good. We know this is necessary. Then it goes on to say something else that I did not anticipate. It goes on to say that that obligation (created by a promise) isn't relieved by the fact that the promise now cannot be kept.
Is this necessary? Yes. It didn't occur to me that an obligation once created can be uncreated. I was simply focused on formally bridging "promise" to the creation of an "obligation." But (D) points out something else just as necessary. That the obligation persists even when it becomes impossible to fulfill that obligation. Indeed that is what the ethicist's example requires. Imagine if (D) were false. That is, imagine if impossibility relieved or excused or unmade the obligation. Then the ethicist's argument is ruined. The example would then contain a situation without an obligation. That example would then become useless to support the conclusion.
Answer Choice (E)
Answer choice (E) does not bridge "promise" to "obligation." It merely says that if some "unforeseen" event "interferes" with the keeping of a promise, then that promise should never have been made to begin with. It's an absurd claim, much like (B), but even if we accept this claim, we get no where on the argument. The consequence of this claim, if we accept it, is just that the promise to meet a friend at a certain time should never have been made to begin with. But the promise was made and the question remains whether that promise made created an obligation. (B) is silent.
More to the point, (B) is unnecessary. We can dispense with this absurd claim without damaging the argument. No, (B), that's just not true. You don't have to judge whether a promise should have been made by looking at whether unforeseen events would interfere with the fulfillment of that promise. You might want to look at whether foreseeable events would interfere. That seems reasonable. Like if you can foresee that you'll be attempting to cross downtown rush hour traffic, then you probably shouldn't promise that the trip will only take 10 minutes. But all of this leaves the argument unaffected. Regardless of whether a promise should have been made to begin with, the fact is that a promise was made and we need to know if that promise created an obligation.
Since many specially bred aquarium fish do not pass their traits to their offspring, their value might diminish overtime for those collectors who hope to breed them.
The fancy tails and strangely shaped fins of specially bred aquarium fish allow them to be outcompeted for food by ordinary fish, which tend not to have fancy tails and strangely shaped fins.
A
Specially bred aquarium fish must receive special care if they are to survive.
B
Connoisseurs are not interested in dull-colored, simply shaped fish.
C
Most specially bred aquarium fish are purchased by connoisseurs.
D
Ordinary fish tend not to have elaborate tails or strangely shaped fins.
E
Strangely shaped fins and elaborate tails interfere with a fish’s ability to reproduce.
Sartore is a better movie reviewer than Kelly. A movie review should help readers determine whether or not they are apt to enjoy the movie, and a person who is likely to enjoy a particular movie is much more likely to realize this by reading a review by Sartore than a review by Kelly, even though Sartore is more likely to give a movie an unfavorable review than a favorable one.
Summarize Argument
The author argues that Sartore is a better movie reviewer than Kelly. The author supports this by asserting that a quality of good movie reviewers is helping readers determine whether or not they will enjoy the movie. What’s more, Sartore fulfils this quality better than Kelly does because Sartore’s reviews are more likely than Kelly’s to make a reader realize what movies they will probably enjoy.
Notable Assumptions
The author assumes that helping readers to determine whether they will enjoy a movie or not is the most important thing that movie reviews should do.
The author also assumes that a person who is likely not to enjoy a movie is equally or more likely to realize this by reading a review by Sartore compared to a review by Kelly.
A
Sartore has technical knowledge of film, whereas Kelly is merely a fan.
This doesn’t strengthen, since the argument only defines a good movie reviewer based on the outcome of their reviews, i.e. helping readers determine which movies they will or won’t like. The background of the movie reviewers is irrelevant.
B
Most of Kelly’s movie reviews are unfavorable to the movie being reviewed.
It’s irrelevant to the argument whether most of the reviews of either critic are positive or negative, as long as the reviews fulfil the criterion of helping readers determine whether or not they will enjoy the movie.
C
One who is apt not to enjoy a particular movie is more likely to realize this by reading a review by Sartore than a review by Kelly.
This strengthens the argument by affirming the assumption that Sartore helps more people than Kelly not just with determining which movies they will enjoy, but also which movies they won’t enjoy.
D
Reading a movie review by Sartore will usually help one to enjoy the movie more than one otherwise would have.
This does not strengthen, because the author never claims that a movie review changing the reader’s enjoyment of the movie influences whether the review is good or not.
E
Most of the movies that Sartore reviews are also reviewed by Kelly.
This is irrelevant, as the argument only compares Sartore and Kelly based on whether their reviews of a given movie will be more likely to help a reader determine whether they would enjoy that movie. It doesn’t matter how much overlap there is between the movies they review.