LSAT Logical Reasoning : LSAT Logical Reasoning
Study concepts, example questions & explanations for LSAT Logical Reasoning
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Example Questions
Example Question #12 : Determining The Flaw In The Argument
Beth: We should stop spending so much time and money on climate change research. From the studies I've read, even if it is an issue, it will not significantly affect our lifestyle for thousands of years. With the pressing problems we face today, we cannot afford to expend our resources in such a way. Besides, it's politically divisive.
Stan: So you'd rather we just turn a blind eye and ignore climate change? It's not just future generations that will be affected by these issues. Having environmental awareness right now will help to solve our energy and waste problems, not to mention the impact on health. You have to look at the bigger picture.
Stan's response to Beth's argument is most vulnerable to criticism on which of the following grounds?
It cites irrelevant data in support of its conclusion.
It appeals to evidence which has not been properly supported.
It fails to recognize the importance of planning for one's future.
It presupposes what it seeks to establish, and ignores potential counterevidence.
It attempts to refute a distorted version of an opposing position.
It attempts to refute a distorted version of an opposing position.
Stan's response focuses on awareness of climate change, whereas Beth's argument was about spending time and funding on climate change research. Therefore Stan distorts Beth's position and attempts to argue against the distorted position. The other answer choices, to the extent that they are valid at all, are not nearly as fundamental to Stan's reasoning.
Example Question #13 : Determining The Flaw In The Argument
The government always protects animals that are at risk of extinction. Further, some animals have become extinct even though they were protected by the government. Black bears must be at risk of extinction because the government recently began protecting them.
The argument is flawed because it does which of the following?
Without support, concludes that bears will become extinct because other animals protected by the government have become extinct
Determined that black bears only recently became at risk of extinction
Assumes that the government only protects animals that are at risk of extinction
Fails to account for the possibility that some animals at risk of extinction will not in fact become extinct
Assumes that some animals are not at risk of extinction
Assumes that the government only protects animals that are at risk of extinction
The argument states that all animals that are at risk of extinction are protected by the government. It does not follow from this, however, that only animals at risk of extinction are protected. The government could protect animals at risk of extinction as well as those that are not.
Example Question #20 : Flaw
Sports agent: College athletes should be paid for their efforts; otherwise, there is no incentive for them to stay in college rather than become professionals in their respective sports. After all, college sports are nearly as popular as professional sports nationwide, and billions of dollars are made annually by television stations, athletic conferences, and associations promoting the sports. Yet the student athletes themselves see none of the money as long as they remain students. The way to keep athletes in school is to begin paying them salaries commensurate with what they would receive as professionals.
The reasoning in the sports agent’s argument is most vulnerable to criticism on the grounds that the argument
fails to adequately support the premises in such a manner that the conclusion would follow from those premises
uses the key term “professional” in two different senses in various parts of the argument
presumes, without providing justification, that college sports are nearly as popular as professional sports nationwide
fails to consider the possibility that many student athletes do not play college sports with the intention of becoming professionals in those sports
bases its conclusion on subjective criteria rather than an objective assessment of the merits of paying student athletes
fails to consider the possibility that many student athletes do not play college sports with the intention of becoming professionals in those sports
The argument creates a false dilemma by assuming that all college athletes plan (and are able) to become professional athletes. The paragraph contains no premise which supports this assumption. The remaining answer choices do not properly identify flaws in the argument’s reasoning.
Example Question #21 : Flaw
Therapists who treat patients for long periods of time develop attachments to the patients. Once such attachments are formed, they are unable to take an objective view of the patients’ symptoms, leading to possible bias and inaccuracy in their diagnoses and treatment. Therefore, to improve the quality of their treatment, patients should switch therapists every three to six months.
The reasoning in the argument is most vulnerable to criticism on the grounds that the argument fails to consider the possibility that
long-term relationships between therapists and patients create benefits in the quality of treatment which outweigh the possible negative consequences of attachments
it is more expensive to switch therapists every three to six months than it is to remain with the same therapist for a long period of time
the quality of a patient’s treatment is often determined by the therapist rather than the patient
not every therapist develops a strong attachment to every one of his or her patients
most inaccuracies in diagnosis or treatment do not necessarily prevent the patient from continuing to progress therapeutically
long-term relationships between therapists and patients create benefits in the quality of treatment which outweigh the possible negative consequences of attachments
The argument’s conclusion states that patients should switch therapists to improve the quality of their treatment, but fails to indicate that the possible bias and inaccuracy resulting from attachments to patients necessarily leads to lower quality treatment. Hence, it is possible that long-term relationships create benefits which outweigh the negative consequences mentioned. The remaining answer choices are either irrelevant or attack the argument’s premises rather than its reasoning and conclusion.
Example Question #22 : Flaw
Theme park executive: While normally our park closes at 9:00 pm, we recently experimented by leaving it open until midnight for a period of one week. We did not expect a significant increase in traffic during nighttime hours. To our surprise, on each day during that week the park was more crowded between 9:00 pm and midnight than it was during any other three-hour period. Therefore, to maximize our attendance, we should leave the park open until midnight all year long.
The reasoning in the theme park executive's argument is flawed on the grounds that it
presumes, without providing justification, that those who remained in the park during the later hours would not have left had the park closed earlier
takes for granted that late-night attendance will remain constant during all seasons of the year
draws a conclusion regarding theme park attendance that merely restates one of the argument's premises
confuses a condition merely necessary for the observed effect to occur for a condition sufficient to cause the observed effect
overlooks the possibility that the experiment's novelty, rather than the operating hours themselves, was responsible for the observed attendance
overlooks the possibility that the experiment's novelty, rather than the operating hours themselves, was responsible for the observed attendance
There is a possible explanation for increased attendance during the late hours which is completely overlooked by the theme park executive: namely, that the late hours only occurred for a week. In other words, it is quite possible that attendance was high during those periods because attendees saw this as a special, one-time event (the equivalent of a product being available "for a limited time"). If the late hours became a permanent fixture of the theme park, the novelty might wear off and there is no indication that attendance would remain high in those circumstances. The argument does not assume that late-night attendance will remain constant throughout the year; rather, it assumes it will remain high enough to be profitable. The remaining answer choices do not accurately describe the argument's reasoning.
Example Question #21 : Flaw
Art history books are always written using elaborate language. Economics books are always written using unsophisticated language. Amanda’s professor wrote a book about the economics of art history. Therefore, the book uses moderately elaborate language.
Which answer choice uses the same flawed reasoning that is used in this example?
Chihuahuas are dogs that always have high-strung personalities. Corgis are dogs that always have mellow dispositions. Taylor has a dog that is a mix between a Chihuahua and a corgi. Therefore, Taylor’s dog has a moderately high-strung personality.
Women who shop at department stores always wear expensive clothing. Women who shop at thrift stores always wear inexpensive clothing. Therefore, women who shop at both department stores and thrift stores wear both expensive and inexpensive clothing.
Email is delivered more quickly than post mail. Post mail is more personal than email. Arnold scanned a letter that he received as post mail and then delivered it to his father using email. Therefore, the email that Arnold sent is both personal and was delivered quickly.
People who go fishing always live along the coast. People who go hunting always live in rural areas. John has property both along the coast and in a rural area. Therefore, John both goes fishing and hunting.
Dresses that are made from cotton are always comfortable. Dresses made from nylon are usually uncomfortable. Andrea bought a dress that is mostly made from cotton, but includes some nylon. Therefore, the dress is mostly comfortable.
Chihuahuas are dogs that always have high-strung personalities. Corgis are dogs that always have mellow dispositions. Taylor has a dog that is a mix between a Chihuahua and a corgi. Therefore, Taylor’s dog has a moderately high-strung personality.
The flawed reasoning follows the pattern that if “A” always has quality “X” and if “B” always has the opposite of quality “X,” then something that is a mix of “A” and “B” will have a moderate amount of quality X.
In the example, “art history books” (=A) always has the quality of “using elaborate language” (=X) However, “economics books” (=B) do not. Therefore, a mix of art history books and economics books (A + B) would use a moderate amount of (X), elaborate language.
In the correct answer, this same reasoning is followed.
Chihuahuas = A
Corgis = B
High-strung personalities = X
Example Question #2 : Identifying Causal Flaws
Advertisement: Coma Cola is the best-tasting cola on the market and we conducted a test using over 1000 cola consumers to prove it. Each consumer was given two identical cups filled with a carbonated beverage from the same fountain. One cup was filled with Coma Cola and the other was filled with unadulterated soda water. Ninety-nine percent of the consumers preferred the Coma Cola. So, Coma Cola is the best tasting cola available.
The advertisement’s reasoning is most vulnerable to criticism on the grounds that it fails to consider whether ___________________
Coma Cola has more or less caffeine than other colas.
The consumers tested had the opportunity to evaluate colas other than Coma Cola.
Any portion of the population is allergic to any of the ingredients in Coma Cola.
The consumers tested had the opportunity to evaluate flavored soft drinks other than colas.
Coma Cola is cheaper or more expensive than other colas.
The consumers tested had the opportunity to evaluate colas other than Coma Cola.
The advertisement's claim, that Coma Cola is the best tasting cola, is based on 99% percent of cola consumers choosing it over soda water. The flaw in the experimental setup is that just because a consumer chooses Coma Cola over soda water, it does not mean that she will choose Coma Cola over any other cola, let alone over all other colas.
The correct answer recognizes that, in order to validly make such a claim, one would have to show a preference for Coma Cola over other colas, not over soda water (or even over other flavored soft drinks, as one of the incorrect answer choices indicates).
Example Question #23 : Flaw
Students that drink green tea while studying have higher test scores than those that drink soda while studying. Tea manufacturers emphasize that students who reported drinking green tea while preparing for a test achieved consistently higher test scores than those students who reported drinking soda while preparing for the same test. If this claim is true, then if the students who drink soda switched to drinking green tea, their test scores will rise.
The reasoning in this argument is flawed because the argument
accepts the conjecture without challenge that green tea is healthier for students than soda
ignores the possibility that students who drink green tea may have other characteristics besides their drink preference that yield to higher test scores than those students who prefer to drink soda
fails to consider the cost difference between a cup of green tea and a can of soda
utilizes an unsupported assumption that soda lowers the IQ of students
does not provide the precise percentage rise in scores of drinking green tea
ignores the possibility that students who drink green tea may have other characteristics besides their drink preference that yield to higher test scores than those students who prefer to drink soda
The author, here, makes the mistake of assuming that drinking green tea raises test scores or that conversely, drinking soda yields lower test scores. Therefore, the author ignores the possibility that there may be other characteristics besides drink preference that determines a test taker’s score. Thus, the correct choice is “ignores the possibility that students who drink green tea may have other characteristics besides their drink preference that yield to higher test scores than those students who prefer to drink soda.”
Example Question #24 : Flaw
Everyone who achieves success must struggle first. Seth has achieved success. Therefore, Seth must have struggled first.
If the author's premise is to be taken as true, what is the flaw in the author's argument?
Seth may achieve success without ever struggling.
Not everyone will both struggle and achieve success.
Seth may have achieved success first and struggled later.
Not everyone who struggles will eventually achieve success.
There is no flaw in the argument.
There is no flaw in the argument.
If the author's premise is true, then there is no flaw in the author's argument. The premise states that everyone who achieves success must struggle first. Therefore, if the premise is true, it is logical to conclude that if Seth has achieved success, he must have first struggled.
Example Question #25 : Flaw
Criminal trials that are tried before a jury end up in guilty verdicts two out of every three times, while trials that are tried before a judge end up in guilty verdicts three out of every four times. Therefore, a criminal defendant has a better chance of receiving a not guilty verdict if he elects to try the case before a jury (made up of jurors) instead of a judge.
Which of the following is a flaw in the argument?
Judges have a better understanding of the law than jurors.
Jurors tend to be more emotional than judges.
Both judges and juries find more defendants guilty than they find defendants not guilty.
Juries deliver longer sentences for guilty defendants when compared to judges.
Several variables affect whether defendants elect a judge or jury trial.
Several variables affect whether defendants elect a judge or jury trial.
The flaw in the argument is best represented by the choice that several variables affect whether defendants elect a judge or jury trial. These variables could influence if a defendant is found guilty or not. For example, defendants who are guilty but who wish to receive shorter sentences may elect the forum in which that is more likely. This could skew the results for guilty verdict rates. None of the other choices represent a flaw in the argument.
All LSAT Logical Reasoning Resources
