Logical Reasoning Sample Questions

This question asks you to identify the point on which Laird and Kim disagree with respect to pure research. Laird identifies two contributions of pure research: its medical applications (“technologies that contribute to saving lives”) and its role in expanding knowledge and providing new ideas. Of these, Laird considers the second contribution to be more worthwhile. Kim, on the other hand, maintains that “Saving lives is what counts most of all.” Since pure research saves lives through medical applications, Kim disagrees with Laird about whether pure research has its most valuable achievements in medical applications. The correct response, therefore, is (D).

Response (A) is incorrect since we can determine, based on their statements, that Laird and Kim agree that pure research “derives its significance in part from its providing new technologies.” Laird explicitly cites the value of pure research with respect to providing new technologies. Kim indicates agreement with (A), at least in the case of medical technologies, by asserting that “Without pure research, medicine would not be as advanced as it is.”

Response (B) is incorrect since we can determine, based on their statements, that Laird and Kim would likely agree that pure research “expands the boundaries of our knowledge of medicine.” Laird notes that pure research provides us with new technologies that have medical applications. Kim points out that “Without pure research, medicine would not be as advanced as it is.”

Response (C) is incorrect. Kim indicates agreement that pure research “should have the saving of human lives as an important goal” since Kim’s position is that “Saving lives is what counts most of all.” Since Laird cites the saving of lives as one way in which pure research is worthwhile or valuable, Laird also indicates agreement that pure research “should have the saving of human lives as an important goal,” although Laird indicates that expanding knowledge and providing new ideas should be an even more important goal of pure research. The same activity can of course have more than one goal.

Response (E) is incorrect. Laird clearly agrees that pure research has value “apart from its role in providing new technologies to save lives,” given that Laird explicitly cites a second way in which pure research is valuable. However, nothing in what Kim says suggests disagreement with (E). Kim’s position is that the greatest value of pure research is its role in providing new technologies to save lives. We cannot infer from this that Kim believes this role to be the only value of pure research.

This question was of medium difficulty, based on the number of test takers who answered it correctly when it appeared on the LSAT.

This question asks you to identify how the executive’s reasoning proceeds. The ads discussed by the executive appeared in two places—in a magazine and on the magazine’s website. Some information is available concerning the effect of the website ads on consumers, but no consumer response information is available about the print ads. The executive’s remarks suggest that the ads that appeared in print and on the website were basically the same, or very similar. The executive reasoned that information about the effect of the website ads could be used as evidence for an inference about how the print ads likely performed. The executive thus used the analogy between the print ads and the website ads to infer something about the print ads. (D), therefore, is the correct response.

Response (A) is incorrect. The executive’s conclusion about the likely consumer response to the print ads does not constitute a prediction, but rather a judgment about events that have already transpired. Moreover, the executive’s conclusion is not based on any reasoning about the cause of the consumer response to the print ads.

Response (B) is incorrect. The executive does conclude that certain events are likely to have transpired on the basis of what was known to have transpired in a similar case, but no distinction can be made in the executive’s argument between events of a general kind and a particular event of that kind. There are two types of events in play in the executive’s argument and they are of the same level of generality—the response to the website ads and the response to the print ads.

Response (C) is incorrect. The executive does not infer a statistical generalization, which would involve generalizing about a population on the basis of a statistical sample. The executive merely draws a conclusion about the likely occurrence of specific events.

Response (E) is also incorrect. The executive does use the comparability of the print and website ads as the basis for the conclusion drawn; however, as noted above, the executive’s conclusion about the likely consumer response to the print ads does not constitute a prediction about future events, but rather a judgment about events that have already transpired.

This was an easy question, based on the number of test takers who answered it correctly when it appeared on the LSAT.

The question asks you to identify the response that can be properly inferred from the passage. The passage indicates that the Quebec Bridge disaster in 1907 and the inquiry that followed caused the engineering “rules of thumb” used in construction of thousands of bridges to be abandoned. Since the Quebec Bridge disaster in 1907 prompted this abandonment, it can be inferred that these were the rules of thumb under which the Quebec Bridge was being built when it collapsed and that these were the rules of thumb used in bridge building before 1907. Further, since the Quebec Bridge collapsed while under construction and the rules of thumb being used were abandoned as a result, it can be inferred that the rules of thumb used in building the Quebec Bridge and bridges prior to 1907 were insufficient to completely assure the safety of bridges under construction. Finally, since the alternative that was adopted in place of the old engineering rules of thumb was to “depend on far more rigorous applications of mathematical analysis,” it can be inferred that the mathematical analysis incorporated in the engineering rules of thumb used prior to 1907 made them insufficient to completely assure the safety of bridges under construction. Thus, (E) is the correct response.

Response (A) is incorrect. (A) asserts that bridges built before about 1907 were unsafe for the public to use because they were built without thorough mathematical analysis. But this conclusion goes far beyond what is established by the passage. The passage gives evidence only about the safety of bridges built before 1907 while they were under construction. It is silent on whether bridges built before about 1907 were safe when open for use by the public. Moreover, the passage indicates that the rules of thumb used in bridge construction before 1907 were abandoned because the use of those rules did not provide adequate assurance of safety for bridges under construction. It does not follow that bridges built using those rules of thumb (those built before about 1907) actually were unsafe, either while under construction or when open for public use.

Response (B) is incorrect in claiming that Cooper’s absence from the construction site caused the breaking off of the cantilever. The passage does not establish that, had Cooper been at the site, he could have successfully intervened to prevent the cantilever from breaking off. By freezing the project, he might have spared lives by stopping work, but there is nothing in the passage to indicate that he necessarily would have prevented the collapse.

Response (C) is incorrect; there is no evidence in the passage about why nineteenth-century bridge engineers relied on their rules of thumb.

Response (D) is also incorrect. While the passage suggests that a more rigorous application of mathematical analysis would have prevented the collapse of the bridge, it offers no evidence that it is the only way the collapse could have been prevented. For example, it might have been prevented had corrective measures been taken in time.

This question was of medium difficulty, based on the number of test takers who answered it correctly when it appeared on the LSAT.

This question asks you to identify the response that most strengthens the argument. The argument concludes that “current theory is wrong in claiming that supernovas of a certain size always produce neutron stars” based on the observation that no evidence has been found of a neutron star left behind by the supernova event of 1987. However, the failure to find evidence of the predicted neutron star does not necessarily indicate that such evidence does not exist. It may instead indicate that the instruments used to search for the evidence are not powerful enough to detect a neutron star in the area where the 1987 supernova event occurred. The argument would thus be strengthened if there was evidence that the search instruments used would in fact be capable of finding the predicted neutron star if that star existed.

Response (B) provides such evidence. If “sensitive astronomical instruments have detected neutron stars much farther away than the location of the 1987 supernova,” then it is less likely that the predicted neutron star is outside the detection range of “the most sensitive instruments ever developed.” Thus, (B) is the correct response.

Response (A) reports that most supernova remnants that astronomers have detected have a neutron star nearby. Since (A) gives no information about the size of the supernovas that produced these remnants, it is possible that all of the remnants detected to date are consistent with the current theory’s claim that supernovas of a certain size always produce neutron stars. (A), therefore, lends no support to the argument that the current theory is wrong in this claim.

Response (C) reports that the supernova of 1987 was the first supernova that scientists were able to observe in progress. This information has no direct bearing on the question of whether this event produced a neutron star and thus cannot be used to strengthen the argument that the current theory is wrong.

Response (D) asserts that several important features of the 1987 supernova are correctly predicted by the current theory. This bolsters the support for the current theory and would thus, if anything, weaken the argument that the current theory is wrong.

Response (E) reports that not all neutron stars are the products of supernova events. Since this information pertains to neutron stars that were not produced by supernovas, it is irrelevant to the question of whether all supernovas of a certain size produce neutron stars, as the current theory claims. Hence, (E) lends no support to the argument.

This was a difficult question, based on the number of test takers who answered it correctly when it appeared on the LSAT.

This question asks you to identify how the reasoning in the political scientist’s argument is flawed. The argument bases its conclusion—that democracy does not promote political freedom—on two sets of historical examples. The first set of examples demonstrates that democracy is not sufficient for political freedom, and the second set demonstrates that democracy is not necessary for political freedom. But it does not follow from these examples that democracy does not promote political freedom. Even if democracy is not, by itself, sufficient for political freedom, it can still promote political freedom by contributing to it in most instances. Even if democracy is not necessary for political freedom, it can still be true that democracy is something that promotes political freedom wherever it is found. Thus, (D) is the correct response.

Response (A) is incorrect. The political scientist’s argument does not indicate that any particular conditions are necessary for political freedom, nor does it indicate that any particular conditions are sufficient to bring about political freedom. Thus the argument could not be said to confuse these two sorts of conditions. Rather, the political scientist’s argument attempts to demonstrate that democracy does not promote political freedom on the grounds that democracy is neither necessary nor sufficient for bringing about political freedom.

Response (B) is incorrect. The argument does fail to consider whether a substantial increase in the level of political freedom would cause a society to become more democratic, but this does not constitute a flaw in its reasoning. The truth of the claim that increased political freedom causes greater democratization would not by itself undermine the political scientist’s conclusion that democracies do not promote political freedom. Nor does that claim engage with the argument’s premises, which are concerned with the effect of democracy on political freedom, not the effect of political freedom on democracy.

Response (C) is incorrect. The “causal claim being made” could only be the argument’s conclusion that democracy does not promote political freedom, which denies that there is a causal connection between democracy and political freedom. The historical examples in the argument are relevant to this claim, however. These examples are an important part of the larger body of historical evidence that one would look to when investigating the issue of whether democracy promotes political freedom.

Response (E) is also incorrect. The political scientist does not express a personal point of view or base the historical examples on such a view. On the contrary, the historical examples themselves are an impersonal, though flawed, basis for the argument’s conclusion.

This was a difficult question, based on the number of test takers who answered it correctly when it appeared on the LSAT.

The journalist states that pharmaceutical companies have both a need for profits to support future research and a moral obligation to provide medicines to those who most need them and cannot afford them. In order to balance these requirements, they have adopted a practice of selling drugs at lower prices in poorer countries. The journalist’s conclusion is that this practice is unjustified. To support this claim, the journalist points out that different individuals in the same nation have differing abilities to pay, but this consideration does not, by itself, establish that the pharmaceutical company’s policy is unjustified. The question asks you to choose the principle that would most help to justify the journalist’s reasoning.

The principle stated in response (C) connects the question of whether special consideration is deserved to personal, rather than societal, needs. The pharmaceutical companies’ practice provides special consideration based on the characteristics of one’s society, and not based on one’s personal needs. As a result, according to this principle, the practice tends to deny special consideration to some who deserve it (the poorer citizens of wealthier nations), while giving special consideration to some who do not deserve it (the middle class citizens of poorer nations). In this way the practice is failing to meet the pharmaceutical companies’ obligation to provide special consideration for those who most need the drugs and cannot afford them, and, in giving undeserved special consideration, failing to generate income that could have been used to support new drug research. The principle in (C) thereby provides strong support for the journalist’s reasoning that the pharmaceutical companies’ practice is unjustified. Thus, (C) is the correct response.

The principle stated in response (A) applies to balancing the consideration deserved by ill people and healthy people. However, the pharmaceutical companies’ practice, and the journalist’s argument against that practice, concerns only ill people (that is, people who need drugs). As a result, response (A) is not relevant to the journalist’s reasoning.

The principle stated in (B) requires that wealthy institutions use some of their resources to aid those in need. This tends to affirm the pharmaceutical companies’ moral imperative to provide medicines to those who need them but cannot afford them. However, this principle gives no support to the journalist’s reasoning, which contends that the pharmaceutical companies’ pricing policy is not justified by this moral imperative.

The principle stated in (D), that people in wealthy nations should not have better access to health care than those in poorer nations, is a principle that tends to support the companies’ practice, because the companies’ practice is one that tends to lessen the health care disparities between wealthy and poorer nations. For this reason, (D) actually runs counter to the journalist’s reasoning.

The principle stated in (E) concerns whether an unequal distribution of health care or an unequal distribution of wealth is more unfair. However, this is a different issue than the one the journalist is addressing. Response (E) is thus not relevant to the journalist’s reasoning.

This was an easy question, based on the number of test takers who answered it correctly when it appeared on the LSAT.

This question asks you to identify the option containing information that makes the conclusion of the argument follow logically. The conclusion of the argument is that it is false that any contemporary poet who writes formal poetry is performing a politically conservative act. To draw this conclusion logically, one only needs to show at least one contemporary poet who is writing formal poetry and is not thereby performing a politically conservative act. Showing such an instance would provide a counterexample to the claim attributed to the critics, demonstrating that the critics’ generalization is false.

The premise given is that there are two contemporary and politically progressive feminist poets who write formal poetry—Molly Peacock and Marilyn Hacker. If no one who is politically progressive is capable of performing a politically conservative act, and Peacock and Hacker are politically progressive, it follows logically that neither is capable of performing a politically conservative act. Since both write formal poetry, their writing of formal poetry cannot be a politically conservative act. This shows that one can write formal poetry without performing a politically conservative act, so (C) is the correct response.

If it is true that no one who is a feminist is politically conservative, as response (A) says, we can conclude that Peacock and Hacker, who are identified as being feminists, are not politically conservative. But we already knew this, as they were also identified as being politically progressive. As long as people who are not themselves politically conservative are capable of performing politically conservative acts, the question of whether it is possible for someone to write formal poetry without performing a politically conservative act remains unanswered. (A) is thus incorrect.

If no poet who writes unrhymed and unmetered poetry is politically conservative, as response (B) indicates, this tells us little about Peacock and Hacker, whose poetry, we are told, is almost exclusively formal. Insofar as (B) may indicate that Peacock and Hacker are not politically conservative (because they write some poetry that is not both rhymed and metered), we already knew this, as they are identified as being politically progressive. Since the argument works by presenting Peacock and Hacker as counterexamples to the claim that to write formal poetry is to perform a politically conservative act, (B) contributes nothing in the way of additional support for the conclusion.

Response (D) says that anyone who sometimes writes poetry that is not politically conservative never writes poetry that is politically conservative. However, to make the conclusion of the argument follow logically, one must show that some contemporary poets who write formal poetry are sometimes not performing a politically conservative act. The information in (D) is not applicable to this question.

Response (E) concerns the effects of the content of a poet’s work on determining the political consequences of the work. However, the question that must be answered is whether any contemporary poet who writes formal poetry is performing a politically conservative act, not what the consequences of that poetry might be. The question of whether writing a particular poem is a politically conservative act is different from the question of what that poem’s political consequences will be. Moreover, because the content of neither Peacock’s nor Hacker’s work has been specified, (E) does not even allow us to draw a conclusion about the political consequences of their work.

This was a difficult question, based on the number of test takers who answered it correctly when it appeared on the LSAT.

This question asks you to find the assumption required by the argument. In other words, find the statement whose truth is required if the argument is to succeed in demonstrating its conclusion.

Response (E) is the correct response. If the bones were not already in the sediments when the lake dried up, that means that they got into the sediments later; that is, less than one-and-a-half million years ago. But then their existence would not provide evidence that there were human ancestors in western Asia between two million and one-and-a-half million years ago; that is, the conclusion of the argument would not follow if (E) is false.

Response (A) is incorrect. The existence of other lakes in the area is irrelevant to the argument.

Response (B) is incorrect. If response (B) turned out to be true, that might provide a reason why humans were in the area of the lake, but this particular explanation need not be assumed in order for the argument to succeed in demonstrating its conclusion.

Response (C) is incorrect. It does not matter for the argument whether or not there were such remains in the lava, and the argument does not state or imply that there were no humans in the region prior to two million years ago. This was by far the most popular incorrect response.

Response (D) is incorrect. The remains could have gotten into the lake in any number of other ways; to give just one, perhaps the people in the area put their dead into the lake.

This was of medium difficulty, based on the number of test takers who answered it correctly when it appeared on the LSAT.

This question asks you to resolve an apparent discrepancy in information. The discrepancy arises because the passage presents two pieces of information that are in conflict.

Response (C) is correct. If only very careful drivers use headlights when their use is not legally required, then this explains why, when headlight use is optional, those drivers are less likely to be involved in a collision than are drivers who use headlights only when visibility is poor. It stands to reason that if headlight use is made mandatory, many less-careful drivers will also use headlights. But then the group of drivers using headlights expands to include not only the very careful drivers, but drivers of all sorts—including some who are not very careful. So it is not at all surprising that the overall number of collisions is not reduced: unsafe drivers do not become more careful when forced to use headlights.

Response (A) is incorrect. Statistical information about the percentage of drivers who use headlights for daytime driving in jurisdictions where such use is optional does not help to explain why making the use of headlights mandatory does not reduce overall collisions.

Response (B) is incorrect. Rather than helping to resolve the apparent discrepancy, this statement would, if true, rule out a possible resolution. If, contrary to response (B), such a law were difficult to enforce, that might help explain why such laws do not reduce collision rates.

Response (D) is incorrect. This choice can do nothing to explain discrepancies between cases in which the use of headlights is optional when visibility is good and cases where the use of headlights is mandatory at all times. This choice introduces a third scenario that does not explain anything about either of the situations discussed in the passage.

Response (E) is incorrect. If it is true that the jurisdictions in which the use of headlights is mandatory are areas that have poor daytime visibility, one might expect the use of headlights to reduce the overall number of collisions, at least in those places. But in any case, response (E) does not explain why, in jurisdictions where use of headlights is optional, drivers who use headlights at all times are less likely to be involved in collisions. This was the most popular incorrect answer.

This was a difficult question, based on the number of test takers who answered it correctly when it appeared on the LSAT.

This question asks you to find the response that contains a pattern of flawed reasoning most similar to that contained in the passage’s argument. To do this, you must understand the flawed pattern in the passage’s argument. Then choose the response that exhibits the most similar flawed pattern.

Response (D) is correct. Just because most As are Bs, that does not mean a particular B is likely to be an A. There may be many more Bs than As. This is the flaw in the passage, and in response (D).

Response (A) is incorrect. This argument is not flawed. Its premises, if true, provide good evidence for drawing its conclusion.

Response (B) is incorrect. This argument is flawed in generalizing from a specific case that may not be representative. But that is not the flawed pattern in the passage’s argument.

Response (C) is incorrect. This argument is not flawed. Its premises, if true, provide good evidence for drawing its conclusion.

Response (E) is incorrect. This argument is not flawed. Its premises, if true, provide good evidence for drawing its conclusion.

This was a very difficult question, based on the number of test takers who answered it correctly when it appeared on the LSAT.