LSAT Logical Reasoning › Determining which answer uses parallel reasoning to the argument provided
Every successful business has a smart CEO or good customer service. The CEO at John's company is not smart, so the company's customer service must be good.
Which of the following most closely resembles the flawed logic exemplified above?
Every famous athlete has immense talent or a good sports agent. Henry's brother plays baseball but is not talented, so he must have a good sports agent.
Every famous athlete has immense talent or a good sports agent. Henry's brother plays baseball and has a good sports agent, so he must have immense talent.
Every famous athlete has immense talent or a good sports agent. Henry's brother plays baseball and has immense talent, so he must have a good sports agent.
Every famous athlete has immense talent or a good sports agent. Henry's brother plays baseball. He is not talented, so he must not have a good sports agent.
Every famous athlete has immense talent or a good sports agent. Henry's brother plays baseball and has immense talent, so he must be a famous athlete.
The passage states, "Every successful business has a smart CEO or good customer service." It says nothing, however, about whether John's company is successful. Therefore, we can't reasonably deduce that it has good customer service just because the CEO isn't smart.
Similarly, we know that Henry's brother plays baseball, but not that he is a famous athlete. Therefore, just because he does not have talent does not mean that he has a good sports agent.
Every successful marriage is built upon trust and compassion. Daniel and Beth do not have a successful marriage. Clearly, they do not trust each other.
Which of the following most closely resembles the flawed reasoning outlined above?
All skyscrapers have a solid foundation and are designed with classical architectural styles. This building is not a skyscraper. It must not have a solid foundation.
All skyscrapers have a solid foundation and are designed with classical architectural styles. This building was constructed with a modernist design. It must not be a skyscraper.
All skyscrapers have a solid foundation and are designed with classical architectural styles. This building has a classical architectural style. It must have a solid foundation.
All skyscrapers have a solid foundation and are designed with classical architectural styles.
All skyscrapers have a solid foundation and are designed with classical architectural styles. This building is not a skyscraper. It was not designed with a classical architectural style.
The reasoning in the passage is flawed because it presumes to know which (if either) of the necessary conditions is not satisfied in order for the marriage to be unsuccessful.
Similarly, just because the building does not qualify as a skyscraper does not mean that we know that its foundation is unstable.
It has been scientifically established that all dogs bark. As a result, any animal that barks is a dog. So, if a person hears an animal bark, that person can safely conclude that the animal is a dog.
Which of the following arguments most closely parallels the flawed reasoning above?
All debt that should be avoided is high interest debt because all high interest debt should be avoided. Debt that should be avoided must be high interest debt.
Only high interest debt is debt that should be avoided. Debt that is not high interest should not be avoided.
High interest debt should sometimes be avoided. As a result, some debt that should be avoided is high interest debt. So, a person can safely conclude that high interest debt should be avoided.
All high interest debt should be avoided. Debt that is not high interest need not be avoided. So, people should prefer low interest debt.
If all high interest debt should be avoided, and if some debt is high interest, then some debt should be avoided.
The argument assumes that if all A are B, then all B must be A. That is the central flaw of the argument because it may be true that all dogs bark and that seals also bark. Similarly, although it may be true that all high interest debt should be avoided, there may be other debt that should be avoided as well. It is important to note that the reasoning can be parallell even when the order of the argument may be slightly different.
If a wine receives a high score from the National Sommelier Association, it is more likely to be sold in fine-dining restaurants. A new wine from Oregon just received a high score from the National Sommelier Association. Therefore, it is more likely to be sold in fine-dining restaurants.
Which of the following choices most closely reflects the reasoning in the argument above?
Pearls that are larger than average are more likely to retail for a higher price. A pearl diver found a dozen pearls that are much larger than average. Therefore, the pearls are more likely to retail for a higher price.
Older coins are more valuable. Anita has a coin believed to have originated from the colonial era, but lacks any proof. Therefore, it is questionable whether her coin is valuable.
Brighter colors attract more attention. The professor attracts a lot of attention. Therefore, he probably tends to wear more bright colors.
Famous actors tend to appear in popular movies. Popular movies often feature famous actors. Therefore, it is unlikely to find a popular movie without famous actors.
Using recycled materials is beneficial to the environment. Some newspapers only use recycled paper in their products. Therefore, a newspaper is likely to be beneficial to the environment.
The flow of reasoning in the argument is that if X has Y quality, then Z is likely to happen.
In the text,
X = wine
Y = receives a high score from the National Sommelier Association
Z = likely to be sold at fine dining restaurants
The correct answer follows this reasoning:
Pearls that are larger than average are more likely to retail for a higher price. A pearl diver found a dozen pearls that are much larger than average. Therefore, the pearls are more likely to retail for a higher price.
X = pearls
Y = larger than average
Z = more likely to retail at a higher price
The local ice cream shop decided to stop offering cappucino-flavored ice cream to its customers. Anna was disappointed by this decision, because cappucino was her favorite ice cream flavor. Therefore, the local ice cream shop intentionally disappointed Anna.
The flawed reasoning above most closely resembles the reasoning in which of the following arguments:
Becca intentionally planted her flowers in the sun. Unfortunately, these particular flowers prefer shade, so the intense sunlight killed the flowers. Therefore, Becca intentionally killed her flowers.
Brittany stole 12.00 from Lindsey and bet it in Vegas. Then Brittany won 200.00 in Vegas. Therefore, Brittany actually stole 200.00 from Lindsey.
The lightning caused the power to go out, and the power outage caused the meat in the refrigerator to spoil. Therefore, the lightning caused the meat in the refrigerator to spoil.
Laura knows that Dungeness Crab is caught in Humboldt Bay, and that Humboldt Bay is in Northern California. Therefore Laura should know that dungeness crab is caught in Northern California.
The treatment plant increased the chlorine in the water, and whatever increased the chlorine in the water is responsible for the decrease in the frog population. Therefore, the treatment plant is responsible for the decrease in the frog population.
The flawed argument states that performing an intentional act led to a certain consequence, and draws the incorrect conclusion that the consequence itself was therefore intended. Similarly, the correct answer choice confuses an intentional act that resulted in a negative consequence with the intent to bring about that consequence.
Economist: All hamburger joints must offer fries and drinks to maximize their revenue. The Burger Shack is a hamburger joint. Because it offers fries and drinks, its revenue is clearly being maximized.
The flawed reasoning in which one of the following is most similar to that in the economist’s argument?
Every piano teacher needs to have a clear course of instruction and a patient personality to succeed. Beverly, a piano teacher, has both of these, so she is undoubtedly successful.
For a video game to sell well, it must include both a memorable character and lots of action. Arkham’s Revenge is a video game that has been selling well. Therefore, it must have a memorable character and lots of action.
Every traffic jam is caused by two factors: impatient driving and lack of available roads. In the city of San Calistranus, there are plenty of available roads and few impatient drivers. So, clearly, there are few traffic jams in San Calistranus.
It will never snow unless the temperature is below 40 degrees and there is sufficient humidity. On Thursday there was sufficient humidity, but the temperature was 45 degrees, so it didn’t snow.
Successful campaigning relies on two factors: powerful action committees and sufficient exposure. Sarah Strong was a congressional candidate in the last election. She must have had a powerful action committee and sufficient exposure, because she ran a successful campaign.
The correct answer choice is the only one which commits the fallacy of affirming the consequent. In other words, both it and the original argument improperly assume the converse of their conditional statements. We know that the Burger Shack needs to offer fries and drinks to maximize its revenue, but we do not know that its revenue is necessarily maximized if it offers them. Likewise, we do not know whether Beverly is a successful piano teacher simply because she has a clear course of instruction and a patient personality.
While there are certain dog-training techniques that generally tend to be effective for most dogs, it is important to keep in mind that each dog will respond particularly well to certain techniques that other dogs might not be receptive to. Therefore, the best practice is to keep general principles in mind when training dogs, while tailoring their educations to their particular traits.
Which of the following propositions does this reasoning above most closely conform to?
While a general set of principles exist for accomplishing a goal, it is important to acknowledge the unique circumstances or qualities that may exist, and to take them into consideration.
Although dogs are different, they are similar enough that a basic set of training principles can be applied to them universally, with slight room for variation.
It is dangerous to apply a broad set of principles to a set of unique individuals because they will react to the same set of circumstances differently.
Unique individuals and unique circumstances call for specialized training to meet their needs.
Even though general principles are broad enough to encompass most individuals or circumstances, there will always be outliers that require special attention.
The correct answer most closely conforms with the excerpt.
The incorrect answers are wrong for the following reasons:
All limes are green. Therefore, any fruit that is green is a lime. If a person sees a fruit that is green, that person may assume that the fruit is a lime.
Which of the following most closely parallels the flawed reasoning above?
Immigration courts adopt more liberal views. Therefore, any court that adopts a more liberal view is an immigration court. If a person encounters a court that has a more liberal view, that person may assume that the court is an immigration court.
Liberal views are often expressed in immigration courts. Therefore, if a person encounters a liberal view, it is likely that the view was expressed in an immigration court.
Immigration courts tend to adopt more liberal views. Therefore, if a person encounters a conservative view, it is unlikely that the view was expressed in an immigration court.
Immigration courts have more liberal views. Therefore, liberal views are only expressed by immigration courts. Therefore, if a person encounters an immigration court, that person can assume that the court will have a liberal view.
Liberal views are expressed in immigration courts. Therefore, immigration courts are liberal. If a person encounters a liberal view, that person can assume that the view was expressed in an immigration court.
The flawed reasoning in the text is as follows:
X has trait Y. Therefore, anything with trait Y must be X. If a person encounters something with trait Y, then it must be X.
The correct answer properly reflects this reasoning. All the other answer choices do not properly follow this pattern: they may leave out a link of the causal reasoning or misconstruct it.
All English Springer Spaniels have long hair. All Rottweilers have short hair. Each of Tina's dogs is a cross between an English Springer Spaniel and a Rottweiler. Therefore, Tina's dogs have medium-length hair.
Which one of the following uses flawed reasoning that most closely resembles the flawed reasoning used in the argument above?
All halogen gases are toxic to humans. All non-radioactive noble gases are non-toxic to humans. "Nobagen" gas is a mixture of a halogen gas and a noble gas. Therefore, "nobagen" gas is moderately toxic to humans.
All typists who practice at least one hour per day can type one hundred words per minute. But some typists who do not practice can also type one hundred words per minute. Mike, a typist, practices thirty minutes per day. Therefore, Mike types fifty words per minute.
All players on the Wildcats have brown hair. All players on the Razorbacks have red hair. Members of the Moye family are on both the Wildcats and the Razorbacks. Therefore, some members of the Moye family have brown hair and others have red hair.
All economists know linear algebra. All physicists know relativistic mechanics. Wilma is both an economist and a physicist. Therefore, Wilma knows both linear algebra and relativistic mechanics.
All cars made by Chord are very well made. All cars made by Fysler are very poorly made. Half of the cars on Jim's lot are very well made and the other half are very poorly made. Therefore, half of the cars on Jim's lot are Chords and half are Fyslers.
The flawed reasoning used in the passage is that a combination of two "parent" items with different attributes necessarily yields a "child" product having attributes that are averages of its parents' attributes. The correct answer uses parallel reasoning inasmuch as the argument uses the fact that halogen and noble gases differ with respect to toxicity to conclude that a combination of such gases would yield a gas having toxicity that is the average of the toxicity of its "parent" gases.
Poet: True sincerity is spoken from the heart, without filters. This form of expression contrasts sharply with what is (sadly) the more common way of speaking: a manner in which communication is made to create a comfortable situation, rather than to speak the truth.
Which of the following individuals best embodies the message that the poet is conveying?
A piano teacher, aggravated at his pupil’s refusal to practice, vents to a colleague that the pupil’s lack of motivation has caused him to feel utterly unmotivated as well.
A writer, outraged that no publishing house has yet agreed to publish his manuscript, sends an angry email to his agent in order to release his frustrations. The writer’s email accuses the agent of not advocating on his behalf with enough zeal.
A student, frustrated with the classroom preparation that she was given to tackle a problem set, respectfully tells her professor that she feels that she was not adequately instructed on the material necessary for her to complete her assignment.
A mother, worried that her son will not earn good grades if he does not start studying, tells him, “If you want to get into college, you really need to start doing your homework.”
While a husband is out with his wife, he wants her to feel loved and appreciated. He tells her in complete honesty that from the moment he saw her, he thought she was stunning and had felt immediately drawn to her.
The piano teacher speaks with the most sincerity because he does not speak with any filters, and has no reason to edit what he says.
The other answer choices are incorrect for the following reasons: