All LSAT Logical Reasoning Resources
Example Questions
Example Question #4 : Determining The Flaw In The Argument
The new music genre, “Eastern Vibe” has elements of different music genres. It has influences from Electronica, Dub Step, Rock, and Pop in its composition. Since it has no element in its composition that is original, it follows that the composition of “Eastern Vibe” cannot be considered original.
Which one of the following is a reasoning error made in the argument?
assuming that because something is true of each of the parts of a whole it is true of the whole itself.
generalizing the instances of a few to all instances.
interpreting a factor as a necessity rather than as a want.
presupposing what is to be proved by contradicting a claim.
deriving a conclusion from preferences rather than evidence.
assuming that because something is true of each of the parts of a whole it is true of the whole itself.
The author argues that the new musical genre copied elements of other genres and is therefore not original. This argument does not necessarily follow as there could be other elements of the genre that are original such as the use of new instruments and sounds or the amalgamation of different sounds to form a new coherent genre. Therefore, something can be true of a whole without it being true of its parts; thus the author makes the error described in the answer choice: “assuming that because something is true of each of the parts of a whole it is true of the whole itself.”
Example Question #3 : Flaw
Doctor X: I disagree with Doctor Y’s proposed treatment plan for Mr. Jones. Doctor Y recommends that Mr. Jones undergo surgery because he is in substantial pain. However, Mr. Jones cannot afford to pay for the procedure or the cost of the hospital stay.
The reasoning in Doctor’s X’s argument is flawed because the argument:
engages in ad hominen attacks
uses evidence concerning the economic feasibility of acting on a recommendation as a basis for questioning of the validity of the recommendation
fails to analyze the issue presented in terms of what is best for the patient
compares the use of short-term versus long-term analysis
does not take into account the comforts and amenities of the hospital where the procedure will be performed
uses evidence concerning the economic feasibility of acting on a recommendation as a basis for questioning of the validity of the recommendation
Doctor X only focuses on whether Mr. Jones can afford the procedure and does not discuss the medical merits of Doctor Y’s recommendation. Therefore, there is a scope shift. In other words, just because Mr. Jones cannot afford Doctor Y’s recommendation does not mean that his recommendation is suspect. This is reflected in the correct answer choice that states Doctor X’s flawed argument, “uses evidence concerning the economic feasibility of acting on a recommendation as a basis for questioning of the validity of the recommendation.”
Example Question #3 : Flaw
Mayor: Critics of the Healthy Eating Bill are delaying passage of this important law because they disagree with the more narrow definition of the term “unhealthy foods.” However, this legislation will place stricter limits on the type of foods that will be available to the public than our current laws. Therefore, by splitting hairs over semantics, these critics show their apathy to the public’s health.
The Mayor’s reply to the opponents of the Healthy Eating Bill is most vulnerable to which of the following criticisms?
It fails to adequately recognize the possibility that the definition of the term “unhealthy foods” determines the impact of the legislation.
It connects the motives of those who oppose the bill with the motives of those who produce soda.
It assumes that does who seek to defeat the Bill will profit from its defeat.
It attempts to defend the reputation of the author of Bill rather than the merits of the actual Bill.
It labels the critics of the Bill as supporters of the fast food industry.
It fails to adequately recognize the possibility that the definition of the term “unhealthy foods” determines the impact of the legislation.
The Mayor’s statement that the critics are “splitting hairs over semantics” indicates that he does not believe that the definition of the term "unhealthy foods" makes a difference to the argument. However, this is only his opinion. In actuality, a more restrictive, narrow definition of the term “unhealthy foods” may make significant difference to the critics of the bill. For example, a definition that excludes foods reputedly considered harmful to the public such as one that includes high fructose corn syrup or trans fat would not have the same impact as one that does; thus, support or criticism for the bill could turn on the definition of “unhealthy foods.” Therefore, the correct choice is: “It fails to adequately recognize the possibility that the definition of the term “unhealthy foods” determines the impact of the legislation.”
Example Question #11 : Flaw
The two opposing armies, Army 1 and Army 2, are the same in regards to size. Since certain diseases that have recently afflicted Army 1 can be attributed to its crowded conditions in its encampment, such diseases must also afflict Army 2.
The reasoning in the argument is most vulnerable to the criticism that it:
fails to take into account other factors that may have caused disease
fails to indicate whether the average life expectancy is lower in Army 1 than Army 2
does not take into account the advent of the germ theory of disease
does not distinguish between those diseases that are treatable and those that are not
presupposes that Army 2 is superior to Army 1
fails to take into account other factors that may have caused disease
The author comes to the hasty conclusion that two armies that share the same size will share the same problem (here disease) associated with the density of their encampments. The author assumes that no other factor could influence the issue, which is not true; e.g. different sanitation procedures, more or better skilled medical personnel, etc. could also influence the incidence of disease. This failure to take into account other alternative explanations is the correct answer choice, “fails to take into account other factors that may have caused disease.”
Example Question #12 : Flaw
Many senators do not listen to their constituents, nor are they reactive to the preferences of the people in their state. These politicians might state that they are acting in accordance with the preferences of the people in their state, but they really are not listening to their constituents because without being reactive to the preferences of the people in their respective states, it is impossible to listen to their constituents. It is clear from this that senators who do not listen to their constituents will be incapable of being reactive to the preferences of people in their state.
The argument above is logically suspect because it:
draws a conclusion that simply restates a claim given in support of that conclusion
blames senators for problems that are outside of their control
does not consider the impact of negative attack advertising
fails to take into account that not every senator wants to listen to his political party instead of his constituents
does not distinguish between doing what is best for one’s constituents and acting in accordance with the preferences of one’s constituents
draws a conclusion that simply restates a claim given in support of that conclusion
Circular reasoning assumes the conclusion and is when the evidence and conclusion are functionally identical. Here, this is the case, and both the evidence and the conclusion are rewrites of each other. Thus, the correct answer choice is, “draws a conclusion that simply restates a claim given in support of that conclusion.”
Example Question #13 : Flaw
Meteorologist: The average temperature last winter was 30 degrees fahrenheit. That was the lowest average temperature for a winter in 20 years. The average temperature this winter will most likely be warmer than last winter's average temperature.
The reasoning in the argument is most vulnerable to the criticism that it
assumes that last winter's average temperature will determine this winter's average temperature
predicts a future event from past events that may have no relationship to the predicted event
suggests that the average temperature in a particular winter can predict the temperature on a particular day
assumes that last winter's average temperature will have no bearing on this winter's average temperature
draws a universal conclusion from information about one event
predicts a future event from past events that may have no relationship to the predicted event
The meteorologist did not establish a relationship between past temperatures and future temperatures. As a result, the conclusion does not necessarily follow from the information given. To remedy this flaw, the meteorologist would need to establish that past temperatures predict future temperatures.
Example Question #14 : Flaw
Patient: The doctor who diagnosed my broken leg and recommended I wear a cast for six months has only seen three prior patients with broken legs. Dr. Green, an orthopedic surgeon, has evaluated thousands of patients who had broken legs. Even though a consultation with Dr. Green is more expensive, he will likely give a more accurate diagnosis of my leg than I got from the prior doctor.
The reasoning in the patient's argument is most vulnerable to criticism on the grounds that the argument
treats a merely necessary condition as though it were a sufficient condition
falsely equates the terms consultation and diagnosis, when one does not necessarily lead to the other
fails to take into account the possibility that Dr. Green may not have been practicing for as long as the other doctor
presumes, without further justification, that a doctor's experience in evaluating patients likely determines the accuracy of his or her diagnosis
fails to specify a source for the claim that the doctor who evaluated the patient's leg has only seen three prior patients with broken legs
presumes, without further justification, that a doctor's experience in evaluating patients likely determines the accuracy of his or her diagnosis
The patient’s fundamental assumption is that Dr. Green’s diagnosis will be more accurate simply because he has more experience in evaluating patients. Yet there is no logical reason to assume this. The other doctor’s diagnosis may be accurate regardless of how many patients he has evaluated.
Example Question #15 : Flaw
Movie critic: Films nowadays rely heavily on special effects and computer graphics to entertain audiences. Fifty years ago, when such technology did not exist, films had to rely on well-written plots and dialogue to keep the audience’s attention. It is clear that today’s written screenplays are not held to the same standards they would have been fifty years ago.
The movie critic’s argument is flawed in that it
assumes that the standards of written screenplays nowadays are lower based solely on the prevalence of special effects and computer graphics
attacks modern screenplays on an aesthetic basis rather than a logical basis
provides no basis for the assertion that certain technology did not in fact exist fifty years ago
fails to consider the possibility that audience’s attention spans were longer fifty years ago, and thus they were more easily entertained
downplays the importance of acting and directing in determining the box office success of films
assumes that the standards of written screenplays nowadays are lower based solely on the prevalence of special effects and computer graphics
Nothing in the argument supports the conclusion that screenplay standards have dropped; all we know is that there are more special effects and computer graphics. Whether these entertain audiences more than the screenplay is beside the point. The movie critic does not address the possibility that modern films could still have well-written plots and dialogue regardless of their special effects.
Example Question #11 : Determining The Flaw In The Argument
Cook: Often times when I cook, I find that I can become over-ambitious and prepare multiple dishes at once. As a result, I don’t always pay enough attention to everything that I am preparing and have a tendency to overcook some of my creations. I have heard about a new type of cookware that is designed to prevent overcooking, and am thinking of investing in it so that I can prepare better food.
The cook’s reasoning is flawed because he is:
confusing cause and effect.
assuming that a condition precedent has already occurred.
relying on information that does not have a credible source.
relying on a sample size that is too narrow.
mistaking correlation for causation.
mistaking correlation for causation.
The cookware is correlated to reduced overcooking. However, the chef thinks that the cookware will cause his food to no longer be overcooked, when the cause of such overcooking appears to be his inability to focus on a single dish because of his excessive multitasking. Therefore, the chef mistakes the cookware that he is using as being the cause of his food being overcooked.
The correct answer identifies the cause/ correlation error that the chef has made.
Example Question #17 : Flaw
Market analyst: Physical media, like DVDs and CDs, will not be sold for much longer. In the past five years, digital movie downloads have increased by 60%, and digital music downloads have increased by 70%. These trends are likely to continue, especially when one considers the fact that digital media content providers are not hampered by the manufacturing and labor costs of physical media.
The reasoning in the argument is most vulnerable to criticism on the grounds that the argument
presumes that the rights to most movies and music will be given to digital media content providers
fails to take into account the possibility that some digital movies and music are illegally downloaded
presumes, without providing justification, that an increase in sales of one type of media necessarily leads to a decrease in sales of another type
fails to provide a source for its claim that digital download trends are likely to continue
fails to define the terms “manufacturing” and “labor”
presumes, without providing justification, that an increase in sales of one type of media necessarily leads to a decrease in sales of another type
The argument provides no data indicating that sales of physical media are decreasing, nor does it explain any connection between increased digital media sales and physical media sales. Without additional information, one could assume that both types of media are increasing in sales. The incorrect answer choices do not attack the argument’s reasoning, but focus on other factors which do not necessarily affect the conclusion.