LSAT Logical Reasoning : Parallel Reasoning
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Example Questions
Example Question #1 : Parallel Reasoning
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?
If all high interest debt should be avoided, and if some debt is high interest, then some debt should be avoided.
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.
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.
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.
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.
Example Question #1 : Parallel Reasoning
Everyone who thinks the Rams would win the championship thought that Jones would receive the award for Most Valuable Player. But Jones did not receive the award for Most Valuable Player. Therefore, anyone who believes the Rams will win the championship is wrong.
Which one of the following arguments contains flawed reasoning most similar to that in the argument above?
Anyone who thinks chickens are ugly thinks ducks are ugly. Since there is no reason to think ducks are ugly there is no reason to think chickens are ugly.
If you believe in fairies then you do not believe in vampires. Since Cindy believes in vampires, she cannot believe in fairies.
Anyone who thinks that eating before exercising is a good idea has never taken a health class. But Jim has never taken a health class and knows that he should not eat before exercising. Therefore, taking a health class is not necessary for you to know eating before exercising is not a good idea.
Anyone that believes that seagulls migrate based on advanced spatial recognition patterns believes that most bird species have highly developed frontal cortexes. But is has been conclusively proven that most bird species do not have highly developed frontal cortexes. Thus, the belief that seagulls migrated based on advanced spatial recognition patterns is false.
Anyone who believes animals deserve better treatment believes that animals are capable of moral judgment. You do not believe that animals deserve better treatment so you do not think they are capable of moral judgment.
Anyone that believes that seagulls migrate based on advanced spatial recognition patterns believes that most bird species have highly developed frontal cortexes. But is has been conclusively proven that most bird species do not have highly developed frontal cortexes. Thus, the belief that seagulls migrated based on advanced spatial recognition patterns is false.
The correct answer parallels the flawed reasoning of the stimulus. Both give a situation where the first argument is dismissed on the basis that the second argument presented is false.
Example Question #3 : Parallel Reasoning
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.
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.
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.
Even though general principles are broad enough to encompass most individuals or circumstances, there will always be outliers that require special attention.
Unique individuals and unique circumstances call for specialized training to meet their needs.
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.
The correct answer most closely conforms with the excerpt.
The incorrect answers are wrong for the following reasons:
- Saying that dogs should be treated the same with "slight room for variation" emphasizes continuity over individualization, and therefore is wrong.
- The statement "It is dangerous to apply a broad set of principles. . . " is not stated in the excerpt.
- "Unique individuals and unique circumstances call for specialized training to meet their needs" exaggerates the need for individualization.
- The concept of "outliers" is not present in the excerpt, a red flag that this is an incorrect answer choice.
Example Question #3 : Parallel Reasoning
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 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.
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.
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 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.
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.
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.
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.
Example Question #2 : Parallel Reasoning
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?
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.
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.
Brighter colors attract more attention. The professor attracts a lot of attention. Therefore, he probably tends to wear more bright colors.
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.
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.
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.
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
Example Question #3 : Parallel Reasoning
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 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.
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 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 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 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 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.
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.
Example Question #5 : Determining Which Answer Uses Parallel Reasoning To The Argument Provided
A high school football coach has made public comments criticizing the decision by the football coaching staff of the local university to not play their star quarterback. However, we should not listen to the high school coach’s criticism. His high school football team has not won a game in several seasons.
The flawed reasoning above most closely resembles which of the following arguments?
We should not listen to the neurobiologist’s predictions about the future state of the economy because he has no formal training in economics.
We should not heed the weather channel's warnings. They have failed to correctly predict the past twenty rainy days.
We should not listen to the car salesperson because she has an incentive to ignore negative features of the car in order to make commission off of a sale.
It is likely that the scholar plagiarized this paper because she has been known to plagiarize in the past.
We should not listen to this art critic's negative comments because it is well known that the art critic is a mediocre artist.
We should not listen to this art critic's negative comments because it is well known that the art critic is a mediocre artist.
The stimulus holds that an opinion is false on the basis that the person with that opinion has made past mistakes in the same area. The correct answer is similar because it follows the same pattern of critiquing a position based on the person with the opinion not the opinion itself.
Example Question #4 : Parallel Reasoning
The Forestry Service has issued new warnings about forest fires, which hikers in the National Forest are encouraged to read thoroughly. The Forestry Service believes that more than two-thirds of forest fires last year were down to human error. Their hope is to seriously curtail the amount of fires for the coming year.
Which statement uses reasoning parallel to the reasoning used in the above statement?
A small business owner adding new pieces to his inventory to increase sales
A company creating a training video to explain new procedures in their warehouses
A football coach instituting a new formation to gain an advantage on opponents
A non-profit organization providing relief to victims of natural disasters
A school having a class that teaches teenagers safer driving practices in order to lower the number of car wrecks
A school having a class that teaches teenagers safer driving practices in order to lower the number of car wrecks
The Forestry Service's main goal is to reduce the number of forest fires from year to year. Their reasoning is that educating people on how fires are started is the most effective way to achieve this goal. Similarly, the school wishes to reduce car wrecks among teenage drivers by educating teenagers about safe driving practices.
Example Question #5 : Parallel Reasoning
Few people have ever seen the initiation rituals of the secret society, as its leadership believes that if anyone reports these deep mysteries then the society will cease to have an attraction.
The reasoning used by the secret society’s leadership is most closely paralleled by __________.
a magician not revealing how tricks are performed in order to keep attracting an audience
a production company not committing itself to any specific future projects
a government agency designating specific documents as classified material
a criminal organization threatening any members who reveal information to law enforcement
a company enforcing a non-disclosure agreement about its new products
a magician not revealing how tricks are performed in order to keep attracting an audience
The secret society keeps its rituals secret, as do all of the other examples given in the answer choices; however, the secret society fosters this secrecy in the hope that it will attract more people to its ranks. This is most similar to a magician keeping secrets in order to attract an audience.
Example Question #6 : Parallel Reasoning
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 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.”
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 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 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.
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.
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.
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:
- There is no evidence in this answer choice that the writer said anything that was sincere in his email; all that we know is that he was releasing his frustration.
- The student does not channel completely unfiltered sincerity given the fact that she is making an effort to “respectfully” communicate her frustrations to her professor. She therefore is using filters in her communication with him.
- The mother is trying to pressure her son to study; she is not expressing her true feelings that she is worried he will not earn good grades.
- Athough the husband is speaking in part from the heart, he is also speaking with the motivation to make his wife happy. This therefore does not comport with the poet’s philosophy.
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