Summarize Argument
The economist concludes that restricting imports to reduce a trade deficit won’t effectively strengthen the economy. She argues that this course of action would be just as ineffective as sticking a thermometer in cold water to lower someone’s fever. This is because, although a country’s trade deficit may indicate economic weakness, the trade deficit does not in itself weaken the country’s economy.
Describe Method of Reasoning
The economist uses an analogy to show that restricting imports to reduce a trade deficit won’t strengthen the economy because the trade deficit isn’t causing economic weakness. She compares it to the pointless act of sticking a thermometer in cold water to lower a fever, suggesting that restricting imports would be just as useless.
A
claiming that a crucial assumption entails a falsehood
The economist never points out a crucial assumption in someone else’s argument, nor does she point out any falsehoods.
B
demonstrating that an analogy explicitly used to establish a certain conclusion is faulty
The economist uses an analogy, but not in the way that (B) describes. (B) suggests that the economist is showing that someone else’s analogy used to support their conclusion is flawed. This is not the case. Instead, she draws her own analogy to support her own conclusion.
C
appealing to an analogy in order to indicate the futility of a course of action
The economist uses an analogy to show that one course of action (restricting imports to reduce a trade deficit) would be just as futile as another course of action (sticking a thermometer in a cold water to lower a fever).
D
calling into question the authority on the basis of which a claim is made
The economist doesn’t question the authority of anyone making any claims. She doesn’t actually challenge any claims at all.
E
showing that a recommended course of action would have disastrous consequences
The economist shows that a particular course of action would be useless. She doesn’t necessarily challenge a “recommended” course of action, and she certainly doesn’t claim that it would have disastrous consequences.
"Surprising" Phenomenon
Why do people enjoy seeing so many movies when most have recycled plots?
Objective
The correct answer will offer an unsatisfactory hypothesis, one that fails to explain why people enjoy seeing movies with unoriginal plots. Every wrong answer, meanwhile, will give a reason for people to enjoy these movies anyway.
A
Movies based on standard plots are more likely to be financially successful than are ones based on original plots.
This is a consequence of those movies’ popularity, not a reason for it. It does not explain why people choose to see them.
B
If the details of their stories are sufficiently different, two movies with the same basic plot will be perceived by moviegoers as having different plots.
This explains why people will see multiple movies with similar plots. If they do not notice that a film's plot is unoriginal, they will not be turned off by that unoriginality.
C
Because of the large number of movies produced each year, the odds of a person seeing two movies with the same general plot structure in a five-year period are fairly low.
This explains why people see new movies each year. Although most movies use recycled plots, the particular movies a given person sees are unlikely to share plots very often.
D
A certain aesthetic pleasure is derived from seeing several movies that develop the same plot in slightly different ways.
This explains why people will see multiple movies every year. They see an unoriginal plot as a positive, one that makes a movie more enjoyable.
E
Although most modern movie plots have been used before, most of those previous uses occurred during the 1940s and 1950s.
This explains why people continue to watch movies even though their plots are largely recycled. Because the movies first using those plots are so old, few viewers have seen them, so the plots are largely novel to the people watching.
Summary
If understanding a word requires knowing the dictionary definition, then understanding a word requires understanding all the words in the definition.
Some babies say things. But they don’t know the dictionary definitions of the words they say.
Some babies say things. But they don’t know the dictionary definitions of the words they say.
Notable Valid Inferences
There are no clear inferences to draw from these facts. One thing that we should definitely NOT infer is the idea that babies don’t understand the words they utter. We don’t know this is true, because we don’t know whether understanding a word requires knowing the dictionary definition.
A
Some babies utter individual words that they do not understand.
Could be false. We don’t know whether understanding a word requires knowing the dictionary definition. The first sentence starts with IF. The IF part of the first sentence is not necessarily true. So maybe babies can understand everything they say. We just don’t know.
B
Any number of people can understand some words without knowing their dictionary definitions.
Could be false. We don’t know that it’s possible to understand a word without knowing the dictionary definition. And even if we did, we don’t know that “any number of people” can understand without dictionary definition.
C
If some words can be understood without knowing their dictionary definitions, then babies understand some words.
Could be false. We don’t know that babies understand words that might be understood without knowing the dictionary definition. Maybe some words can be understood by teenagers and adults, but not necessarily babies.
D
If it is possible to understand a word without knowing its dictionary definition, then it is possible to understand a word without having to understand any other word.
Could be false. If it’s possible to understand a word without knowing the dictionary definition, it still could be the case that we need to understand other words. The stimulus doesn’t tell us what happens if understanding doesn’t require knowing dictionary definitions.
E
If some babies understand all the words they utter, then understanding a word does not always involve knowing its dictionary definition.
Must be true. If some babies understand everything they say, and we know from the stimulus that they don’t know the dictionary definitions of those words, that means understanding does not require knowing the dictionary definition.
Summarize Argument
The argument concludes that for peppered moths, which avoid predators by camouflaging themselves against trees, the darkest moths are the least likely to be spotted and eaten by predators. This is backed up with an observation that the lightest moths are the most visible against trees, so are most likely to be eaten.
Identify and Describe Flaw
The argument uses observations about the lightest moths being the most visible to support a conclusion about the darkest moths being the least visible. However, knowing which color is most visible doesn’t actually tell us which color is least visible.
For example, if trees are usually an intermediate shade between dark and light, the darkest moths may be more visible than average-colored moths.
For example, if trees are usually an intermediate shade between dark and light, the darkest moths may be more visible than average-colored moths.
A
The argument overlooks the possibility that light peppered moths had more predators than dark peppered moths.
The number of predators a moth has is irrelevant to the likelihood of a given predator noticing that moth when it tries to blend into its background, so this isn’t something the argument had to account for.
B
The argument takes for granted that peppered moths are able to control the degree to which they blend into their backgrounds.
The argument does not take this for granted—the whole point is that how different moths are colored affects their ability to blend into their backgrounds.
C
The argument presumes, without providing justification, that all peppered moths with the same coloring had the same likelihood of being seen and eaten by a predator.
The argument does not make this presumption. The entire argument is about the overall likelihood of moths being eaten based on their color, not the odds for any individual moth.
D
The argument overlooks the possibility that there were peppered moths of intermediate color that contrasted less with their backgrounds than the darkest peppered moths did.
The argument jumps straight from the lightest moths being the most visible to conclude that the darkest moths are the least visible, without considering that intermediate-colored moths might be even less visible. This means the conclusion relies on a baseless assumption.
E
The argument presumes, without providing justification, that the only defense mechanism available to peppered moths was to blend into their backgrounds.
The argument is focused on how effective the moths’ camouflage is based on color, so any other defense mechanisms they may have are irrelevant.
Historian: The standard “QWERTY” configuration of the keys on typewriters and computer keyboards was originally designed to be awkward and limit typing speed. This was because early typewriters would jam frequently if adjacent keys were struck in quick succession. Experiments have shown that keyboard configurations more efficient than QWERTY can double typing speed while tremendously reducing typing effort. However, the expense and inconvenience of switching to a new keyboard configuration prevent any configuration other than QWERTY from attaining widespread use.
Summary
The standard QWERTY style of keyboard was designed to slow down typing speed, because it was originally designed for early typewriters. These typewriters could jam if keys were typed too quickly. There exist faster keyboard configurations, but these aren’t used widely, because it would be too expensive and inconvenient to switch away from the QWERTY configuration, which people are used to.
Strongly Supported Conclusions
The original purpose of the QWERTY configuration has resulted in the standardization of a format that doesn’t allow for the fastest typing speed.
If keyboards were designed for something that didn’t jam when typing too quickly, a non-QWERTY keyboard configuration might have been used.
A
Most people who have tried typing with non-QWERTY keyboards have typed significantly more quickly using those keyboards than they usually have done using QWERTY keyboards.
Unsupported, because we only know that there are some faster configurations. There could be many others that are equally slow. And, most people might not be able to type faster even if the configuration makes it possible. They might need training and experience to type faster.
B
Early QWERTY typewriters were less likely to jam than were at least some more recent typewriters if adjacent keys were struck in quick succession.
Unsupported. We don’t have a comparison between early and later typewriters. If anything, we might suspect early typewriters were more likely to jam than later ones, assuming that technology improved in the later ones, allowing for faster typing.
C
If the designers of early typewriters had foreseen the possibility that technology would make it possible for adjacent keyboard keys to be struck in rapid succession without jamming, then they would not have proposed the QWERTY configuration.
Unsupported, because the designers of early typewriters would still be working within the limitations of the then-current technology. They still had to deal with the fact early typewriters could jam if typed too quickly.
D
The benefit to society that would result from switching to a keyboard configuration other than QWERTY is significantly greater than the overall cost of such a switch.
Unsupported, because the stimulus doesn’t give us enough to evaluate the costs and benefits of a new configuration. We know that switching would be costly and inconvenient, and we don’t know whether the benefit of faster typing would outweigh those costs.
E
If the keyboard had been designed for computers, then it would not have been designed to limit typing speed.
Strongly supported, because we know the QWERTY keyboard was designed to limit typing speed because they were designed for early typewriters. If keyboards were designed for something that did not jam when typed quickly, they probably wouldn’t have needed to limit typing speed.
Summarize Argument
The argument concludes that having a legal obligation to perform a certain action is the same as having agreed to perform that action. Why? Because agreeing to perform an action obligates someone to perform that action. From this, the argument draws the sub-conclusion that being obligated to perform an action must mean that one has agreed to perform that action.
Identify and Describe Flaw
The argument has a cookie-cutter flaw: confusing sufficient and necessary conditions. Just because an agreement to perform an action is sufficient to create an obligation to perform that action, that doesn’t mean an agreement has necessarily been made for every obligation. There might be other ways an obligation is formed.
The argument also baselessly treats “legal obligations” and “obligations” as equivalent by saying that they are “the same.”
The argument also baselessly treats “legal obligations” and “obligations” as equivalent by saying that they are “the same.”
A
The argument fails to make a crucial distinction between an action one is legally obligated to perform and an action with good consequences, and it takes for granted that everything true of legal obligations is true of obligations generally.
The argument doesn’t deal with actions with good consequences at all, so it isn’t a flaw to not distinguish them from legally obligated actions.
B
The argument takes for granted that there are obligations other than those resulting from agreements made, and it fails to consider the possibility that actions that uphold agreements made are sometimes performed for reasons other than to uphold those agreements.
The argument doesn’t take for granted that there are obligations that don’t result from agreements, or even consider that possibility. It’s also irrelevant to the argument why people make actions that uphold agreements.
C
The argument contains a premise that is logically equivalent to its conclusion, and it takes for granted that there are only certain actions that one should agree to perform.
The argument’s premise is not equivalent to its conclusion, and it doesn’t make any claims about what kinds of actions one should or shouldn’t agree to perform.
D
The argument treats a condition that is sufficient to make something an obligation as also a requirement for something to be an obligation, and it takes for granted that any obligation to perform an action is a legal obligation.
The argument treats a sufficient condition for an obligation—agreeing to perform an action—as a necessary condition, without considering that obligations can come from other sources. It also claims that legal obligations are “the same” as any other obligation to act.
E
The argument rests on an ambiguous use of the term “action,” and it fails to consider the possibility that people are sometimes unwilling to perform actions that they have agreed to perform.
The argument uses the term “action” consistently. It also doesn’t make any claims about people’s willingness to perform actions they’ve agreed to, only about their obligation to do so.
Summarize Argument
Predicting an invention is self-contradictory. Why? Because predicting an invention entails developing a detailed conception of how that invention will function. But if you manage to do that, congrats, you just invented the thing. So that’s not prediction. That’s just invention. Hence, predicting an invention is impossible.
Describe Method of Reasoning
Author argues that something (predicting an invention) is impossible because a necessary condition of that something (developing a detailed conception of how that invention will function) rules that something out by definition (you can’t predict an invention that already exists).
A
constructing a counterexample to a general hypothesis about the future
Descriptively inaccurate. Author does not construct a counterexample. There is no general hypothesis about the future to disprove.
B
appealing to definitions to infer the impossibility of a kind of occurrence
Descriptively accurate. The author implicitly appeals to the definition of “predict” (stating that something will happen) and explicitly appeals to the definition of “invent” (developing a detailed conception) to infer that a kind of occurrence (predicting an invention) is impossible.
C
countering a hypothesis by indicating the falsehood of the implications of that hypothesis
Descriptively inaccurate. We’ll grant that the “hypothesis” is that “it’s possible to predict an invention.” But the author does not demonstrate that the implications of that hypothesis are false. Rather, the author demonstrates that the hypothesis is self-contradictory.
D
pointing out how a problem is widely thought to be scientific yet is really conceptual
Descriptively inaccurate. Argument does not contain any problem that is “widely thought to be scientific” nor does the author point out any problem as being actually “conceptual.”
E
attempting to show that predicting any event implies that it has in fact already taken place
Descriptively inaccurate. Author does not attempt to show that predicting any event implies that it has in fact already taken place. That would mean prediction in general would be impossible. Author only attempts to show that predicting a specific type of event (inventions) would be impossible.