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Argument Evaluation

289 questions

All types289Multiple choice150Multiple select23True / False57Matching59
Question 61Question →

Below are five brief arguments, each containing a specific logical vulnerability. Match each argument on the left to the abstract description of its flawed reasoning on the right.

Click a left item, then click its matching right item

Items

The architectural commission mandates that all historical district renovations maintain a 'conservative' aesthetic. The proposed gallery renovation relies on energy-efficient materials that conserve resources more effectively than traditional counterparts. Hence, the gallery's proposal fully satisfies the commission's aesthetic mandate.
An ecosystem can attain long-term equilibrium only if its apex predator population remains tightly constrained. In the sprawling northern taiga, recent conservation efforts have successfully implemented strict hunting quotas that keep the wolf population rigidly controlled. Consequently, the taiga ecosystem will soon achieve long-term equilibrium.
A recent survey of established novelists indicates a strong positive correlation between the frequency with which a writer hand-writes drafts and the critical acclaim their published works receive. It follows that aspiring novelists looking to maximize their critical reception ought to abandon their word processors in favor of pen and paper.
Each individual musician in the newly formed metropolitan symphony orchestra is a globally recognized virtuoso known for flawless timing and impeccable pitch. Therefore, the orchestra's inaugural performance will undoubtedly be a masterpiece of unified and perfectly synchronized musical expression.
In a recent poll of subscribers to 'Culinary Avant-Garde' magazine, over 80% reported that they strongly prefer molecular gastronomy techniques over traditional cooking methods. Therefore, we can safely conclude that the general dining public is rapidly losing interest in traditional cuisine.

Matches

Show answer & explanation

Answer

The correct pairings logically link each stimulus to its specific formal reasoning error: Argument 1 demonstrates Equivocation; Argument 2 commits a Necessary vs. Sufficient condition flaw; Argument 3 contains a Correlation vs. Causation error; Argument 4 commits a Fallacy of Composition; and Argument 5 relies on an Unrepresentative Sample.
The correct matches accurately pair each flawed argument stimulus with the formal description of its logical error, representing standard LSAT reasoning vulnerabilities such as Equivocation, Conditional Logic errors, Causal Flaws, Composition Flaws, and Sampling Flaws.

Step-by-Step Solution

1
Analyze Argument 1 to identify how the term 'conservative' is used differently in the premise versus the conclusion.
Identifies equivocation on the word 'conservative'.
Tracking term definitions is essential when a conclusion relies on satisfying a mandate.
2
Evaluate Argument 2's conditional logic regarding ecosystem equilibrium and apex predators.
Recognizes the confusion between a necessary condition and a sufficient condition.
The premise states equilibrium happens 'only if' predators are constrained, but the conclusion treats it as a guarantee.
3
Assess Argument 3's inference about hand-writing drafts and critical acclaim.
Identifies a flawed leap from correlation to causation.
The argument observes a correlation but prescribes an action, assuming direct causality without eliminating alternative explanations.
4
Examine Argument 4's reasoning moving from individual musicians to the orchestra as a whole.
Recognizes the part-to-whole composition fallacy.
Individual traits (virtuosity) do not automatically transfer to the collective entity (orchestral synchronization).
5
Analyze Argument 5's use of a subscriber poll to make a general claim.
Identifies an unrepresentative sample flaw.
The sample group is highly biased toward avant-garde cuisine and cannot represent the general public.

Key Concept

Identifying Formal and Informal Logical Flaws in Arguments
Question 62Question →

Art Historian: The planned restoration of the municipal fresco will undoubtedly destroy the centuries-old patina that has developed on its surface. Nevertheless, the restoration should proceed. The process will successfully remove centuries of grime to uncover the brilliant pigments originally applied by the fresco's creator.

Which one of the following principles, if valid, most helps to justify the art historian's reasoning?

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Answer: Any art restoration process that uncovers the original pigments applied by the creator should proceed, regardless of whether it destroys a centuries-old patina.

Answer

The principle stating that any process uncovering original pigments should proceed regardless of destroying a patina.
The correct answer perfectly bridges the logical gap in the stimulus. The art historian argues that because the restoration uncovers original pigments, it should proceed, despite the cost of destroying the patina. By providing a universal rule stating 'If a process uncovers original pigments, it should proceed regardless of destroying a patina', this answer choice logically forces the historian's conclusion to be true when combined with the stated premises.

Step-by-Step Solution

1
Identify the conclusion of the argument.
The conclusion is: 'the restoration should proceed.'
This is the primary claim the art historian is trying to prove.
2
Identify the premises supporting the conclusion.
Premise 1: The restoration will destroy a centuries-old patina. Premise 2: The restoration will uncover the brilliant pigments originally applied by the creator.
These are the facts provided to support the conclusion.
3
Identify the logical gap in the argument.
The argument jumps from a factual statement about uncovering pigments and destroying a patina to a normative conclusion that the action 'should proceed'.
Factual premises alone cannot logically entail a 'should' conclusion without a guiding principle.
4
Formulate a sufficient rule to bridge the gap.
If a project uncovers original pigments (even if it destroys a patina), then the project should proceed.
A 'justify' question requires a principle that, when added to the premises, guarantees the truth of the conclusion.

Key Concept

Principle - Justify
Question 63Question →

Marine biologist: In the coastal waters of Mako Bay, the overall density of kelp forests has decreased by nearly 30% over the past five years. During this exact same timeframe, the population of purple sea urchins, which aggressively graze on kelp, has doubled. It is clear that the surging purple sea urchin population is responsible for the decline of the kelp forests.

Which of the following, if true, most strengthens the marine biologist's argument?

Show answer & explanation

Answer: In sections of Mako Bay where researchers successfully prevented purple sea urchin populations from increasing, the density of kelp forests remained stable over the past five years.

Answer

The statement showing that kelp forests remained stable in areas where sea urchins did not increase.
The marine biologist concludes that an increase in sea urchins caused the decline in kelp based merely on the fact that both events happened concurrently. A highly effective way to strengthen a causal conclusion is to demonstrate that when the purported cause is removed or absent, the effect is also absent. The correct option provides a control scenario within the same environment: in areas where the urchin population did not grow, the kelp did not decline. This strongly supports the idea that the urchins are indeed responsible.

Step-by-Step Solution

1
Identify the argument's premises and main conclusion.
Premise: Kelp decreased by 30% while urchins doubled. Conclusion: The urchin increase caused the kelp decrease.
Understanding the structure is required to evaluate what would bolster the argument's logic.
2
Determine the type of reasoning used in the argument.
The argument uses causal reasoning based on a correlation (two things happening at the same time).
Causal arguments have specific vulnerabilities and standard ways to be strengthened.
3
Anticipate what kind of evidence would strengthen this causal claim.
Evidence could eliminate an alternate cause, show that when the cause is absent the effect is absent, or show that the cause and effect always occur together.
Pre-phrasing helps quickly identify the correct structural match among the options.
4
Evaluate the options against the anticipated strengtheners.
The option describing sections of the bay where urchins were kept from increasing and kelp remained stable perfectly matches the 'cause absent, effect absent' method.
This isolates the variable (urchin population) to demonstrate its direct impact on the kelp, ruling out bay-wide environmental factors.

Key Concept

Strengthening Causal Arguments
Question 64Question →

Chef Mario’s new signature pasta dish features locally sourced organic white truffles. These truffles cost the restaurant significantly more per ounce than any other ingredient currently used in the kitchen. Because of the extreme cost of this single ingredient, Chef Mario's new pasta dish will have the highest menu price of any item offered at the restaurant.

Which of the following assumptions are logically necessary for the conclusion to be properly drawn? (Select all that apply)

Select all that apply

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Answer: The menu prices of the dishes at Chef Mario's restaurant are influenced, at least in part, by the cost of the ingredients used to make them.; There is no other dish on the menu whose combination of ingredients results in a total ingredient cost higher than that of the new pasta dish.

Answer

The correct assumptions are that the restaurant's ingredient costs actually influence its menu prices, and that no other dish on the menu has a higher total ingredient cost.
For the argument's conclusion to logically follow, two unstated premises must be true. First, there must be a relationship between the cost of ingredients and the final menu price. If the restaurant determined prices randomly or based solely on prep time, the conclusion would fail. Second, the argument relies on a single ingredient's per-ounce cost to make a claim about the total price of a dish. This requires assuming that no other dish uses a large enough quantity of other ingredients to surpass the pasta's total cost.

Step-by-Step Solution

1
Identify the core premises of the argument.
Premise: Truffles cost more per ounce than any other ingredient in the kitchen.
Understanding the foundation of the argument is required to find the logical gap.
2
Identify the main conclusion.
Conclusion: The new pasta dish will have the highest menu price of any item.
The necessary assumption must bridge the premises to this specific conclusion.
3
Identify the logical gaps between the premises and the conclusion.
Gap 1: The argument assumes ingredient cost dictates menu price. Gap 2: The argument assumes that having the most expensive single ingredient means having the highest total overall cost.
Conclusions often introduce new terms or comparisons not fully supported by the premises.
4
Apply the Negation Test to the candidate assumptions.
If menu prices are NOT based on ingredient costs, or if another dish has a higher total cost, the conclusion that the pasta dish will be the most expensive falls apart.
A necessary assumption is one that, if proven false, destroys the argument.

Key Concept

Necessary assumptions bridge unstated gaps in reasoning (Supporter) or rule out scenarios that would destroy the conclusion (Defender).
Question 65Question →

Biologist: The presence of xylotoxin in the venom of the deep-sea viperfish has traditionally been explained as an evolutionary adaptation for immobilizing highly evasive prey. However, we now know that the viperfish's primary food source, the sluggish abyssal slug, possesses complete immunity to xylotoxin. Given that the viperfish only rarely encounters highly evasive species in its deep-sea habitat, the xylotoxin must actually serve a strictly non-predatory physiological function.

Evaluate the following statement regarding the argument above:

The biologist's argument logically depends on the assumption that an evolutionary trait cannot be maintained in a species exclusively for a predatory function that is utilized only on rare occasions.

Show answer & explanation

Answer: True

Answer

True
The statement is True because it articulates a bridge assumption required for the conclusion to hold. The author concludes that xylotoxin MUST have a non-predatory function solely because its predatory target is encountered 'only rarely'. For this definitive conclusion to be valid, it must be inherently true that rare usage is insufficient to exclusively maintain such an evolutionary trait. If rare usage were sufficient, the conclusion would immediately fail.

Step-by-Step Solution

1
Identify the main conclusion and the premises supporting it.
Conclusion: Xylotoxin must serve a strictly non-predatory physiological function. Premises: Its primary prey is immune, and the evasive prey it was thought to target is only rarely encountered.
Deconstructing the argument is the essential first step in identifying logical gaps.
2
Analyze the logical gap between the premises and the conclusion.
The biologist jumps directly from 'the predatory function is used rarely' to the absolute claim that 'the toxin MUST serve a non-predatory function.'
Identifying the shift in scope or logic reveals what the author inherently takes for granted.
3
Apply the Negation Test to the provided statement.
Negated statement: 'An evolutionary trait CAN be maintained in a species exclusively for a predatory function that is utilized only on rare occasions.'
The Negation Test is the definitive method for proving if an assumption is strictly necessary.
4
Evaluate the impact of the negated statement on the argument's conclusion.
If the negated statement is true, the toxin could exist solely for those rare encounters, destroying the conclusion that it must serve a non-predatory function. Therefore, the original statement is strictly necessary.
If negating an assumption destroys the argument, the assumption is logically required.

Key Concept

Necessary Assumption and the Negation Test
Question 66Question →

Every painting acquired by the city museum before 1900 is considered part of the permanent collection. Therefore, every painting acquired by the museum before 1900 must be displayed on the first floor of the building.

Which one of the following, if assumed, enables the argument's conclusion to be properly drawn?

Show answer & explanation

Answer: Every painting that is part of the permanent collection must be displayed on the first floor of the building.

Answer

The correct assumption is that every painting that is part of the permanent collection must be displayed on the first floor of the building.
The argument provides the premise (A -> B) and draws the conclusion (A -> C). To make this logically valid, we must bridge the gap between B and C with the rule (B -> C). The correct answer explicitly provides this missing rule: if a painting is in the permanent collection, it must be displayed on the first floor.

Step-by-Step Solution

1
Identify the argument's premise.
If a painting was acquired before 1900, it is part of the permanent collection (Acquired Before 1900 -> Permanent Collection).
This establishes the starting condition of the logic chain.
2
Identify the argument's conclusion.
If a painting was acquired before 1900, it must be displayed on the first floor (Acquired Before 1900 -> First Floor).
This is the final destination the author is trying to prove.
3
Find the logical gap between the premise and the conclusion.
The argument leaps from 'Permanent Collection' in the premise to 'First Floor' in the conclusion without connecting them.
For the conclusion to be 100% guaranteed, there must be no unconnected terms.
4
Formulate the necessary bridge to guarantee the conclusion.
We must state that anything in the permanent collection must go to the first floor (Permanent Collection -> First Floor).
Chaining 'Acquired Before 1900 -> Permanent Collection' with 'Permanent Collection -> First Floor' deductively yields 'Acquired Before 1900 -> First Floor'.

Key Concept

Sufficient Assumption conditional chaining
Question 67Question →

Below are four distinct causal arguments and four potential pieces of evidence. Pair each argument with the single piece of evidence that most effectively bolsters its specific conclusion by addressing an underlying logical vulnerability.

Click a left item, then click its matching right item

Items

Researchers observed that employees utilizing standing desks report fewer instances of lower back pain than those using traditional seated desks. They conclude that standing desks directly alleviate back pain.
Following the introduction of an invasive hawk species to Elmwood Forest, the population of native ground squirrels declined sharply. Biologists conclude that the hawks are aggressively hunting the ground squirrels.
A recent educational study shows that students who learn to play a musical instrument score significantly higher on standardized math tests. The authors conclude that musical training actively enhances mathematical reasoning skills.
After the city of Morovia initiated a comprehensive tree-planting campaign in its downtown district, average summer daytime temperatures there dropped by two degrees. Planners assert the new trees directly caused this cooling effect.

Matches

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Answer

Match the Standing Desks argument with the evidence ruling out outside exercise; the Hawk argument with the evidence ruling out starvation/disease; the Musical Training argument with the evidence showing no initial math advantage; and the Tree Planting argument with the evidence regarding neighboring municipalities.
Each correct pairing successfully matches a causal argument with the specific piece of evidence that patches its unique logical vulnerability. By ruling out alternative causes (exercise, starvation/disease), eliminating selection bias (pre-existing math skills), and providing a negative control group (neighboring cities), each piece of evidence significantly increases the probability that the stated conclusion is true.

Step-by-Step Solution

1
Analyze the Standing Desks argument to identify its logical gap.
The argument assumes a correlation between desk type and pain reduction implies causation, ignoring the possibility that standing desk users might simply have healthier habits overall.
Identifying the unstated assumption is necessary to find the evidence that protects the argument from that specific vulnerability.
2
Select the evidence that addresses the gap in the Standing Desks argument.
The evidence stating that standing desk users do not engage in more back-strengthening exercises effectively rules out a major alternative cause, thereby strengthening the original claim.
Ruling out alternative causes is a primary method of strengthening a causal argument.
3
Analyze the Hawk and Squirrel argument and match it with corresponding evidence.
The argument assumes the new predator caused the prey decline. The evidence showing abundant food and no disease rules out the other two most common causes of animal population collapse.
Eliminating alternative explanations strengthens the likelihood that the stated cause is the correct one.
4
Analyze the Musical Training argument and match it with corresponding evidence.
The argument is vulnerable to selection bias. The evidence showing no initial math advantage proves the groups started equal, meaning the music training is the most likely cause of the later divergence in scores.
Establishing a neutral baseline rules out the possibility that the 'effect' actually preceded the 'cause'.
5
Analyze the Tree Planting argument and match it with corresponding evidence.
The argument assumes the local intervention caused the cooling. The evidence showing neighboring cities warmed up provides a control group that isolates the tree planting as the active variable.
Demonstrating that an effect did not occur where the cause was absent strongly supports a causal relationship.

Key Concept

Strengthening causal arguments requires addressing specific vulnerabilities: ruling out alternative explanations, eliminating selection bias, and utilizing control groups to demonstrate cause-without-effect controls.
Question 68Question →

Literary Critic: A novel can be considered a genuine masterpiece only if it profoundly disrupts the reader’s pre-existing worldview. Yet, the vast majority of critically acclaimed novels published during the past decade rely strictly on familiar narrative tropes that serve only to validate readers' existing ideological biases. Consequently, it is highly unlikely that future literary historians will recognize any of these recently acclaimed novels as genuine masterpieces.

Which one of the following is an assumption on which the literary critic's argument depends?

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Answer: Future literary historians will not recognize a novel as a genuine masterpiece if it serves only to validate readers' existing ideological biases.

Answer

The argument assumes that future literary historians will not recognize a novel as a genuine masterpiece if it serves only to validate readers' existing ideological biases.
The critic’s logic requires a bridge between a novel lacking the true qualities of a masterpiece and future historians properly withholding that title. The premises establish that recent novels fail the test for being true masterpieces because they validate rather than disrupt biases. However, the conclusion jumps to what historians will *recognize*. For this to hold true, it must be assumed that historians won't mistakenly grant masterpiece status to these exact types of flawed novels. Applying the Negation Test confirms this: if future historians *would* recognize novels that only validate biases as masterpieces, then the conclusion that they won't recognize these recent novels falls apart entirely.

Step-by-Step Solution

1
Identify the core conclusion of the argument.
The conclusion is that future literary historians will likely not recognize recent acclaimed novels as genuine masterpieces.
This is the final claim that the author is trying to prove using the provided evidence.
2
Identify the premises supporting the conclusion.
Premise 1: A masterpiece must disrupt the reader's worldview. Premise 2: Recent acclaimed novels only validate existing biases (meaning they do not disrupt worldviews).
Understanding the evidence is necessary to spot the logical leap the author makes to reach the conclusion.
3
Spot the gap or shift in language between the premises and the conclusion.
The premises establish that recent novels are *not actually* masterpieces. The conclusion claims that future historians will not *recognize* them as masterpieces.
Many LSAT flaws rely on the subtle distinction between objective reality (what a thing is) and subjective evaluation (how a thing is judged or recognized).
4
Apply the Negation Test to candidate assumptions to verify which one is strictly necessary.
Negating the correct option yields: 'Future historians WILL recognize a novel as a masterpiece even if it only validates biases.' If this were true, the fact that recent novels only validate biases would not prevent historians from recognizing them as masterpieces, and the argument would collapse.
The Negation Test is the definitive method for confirming a Necessary Assumption.

Key Concept

Evaluating the gap between objective fact and subjective recognition in Necessary Assumption questions.
Estimated Time:2m 0s
Question 69Question →

Identify the specific reasoning error in each of the following arguments by linking the short stimulus to its corresponding logical flaw description.

Click a left item, then click its matching right item

Items

Dr. Smith claims that our new diet plan is unhealthy. But Dr. Smith was recently fired from his job for being chronically late, so his criticism should be ignored.
The new sci-fi movie is definitely the most popular film of the year because everyone is going to see it.
I always wear my lucky socks when I play tennis, and I won my match today. Therefore, my lucky socks caused me to win.
We should adopt the new tax policy. After all, a famous actor who has starred in many successful action movies says it is the best economic plan for the country.

Matches

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Answer

The argument attacking Dr. Smith matches with rejecting a claim based on personal characteristics. The movie popularity argument matches with assuming the truth of the conclusion. The lucky socks argument matches with concluding causation from correlation. The tax policy argument matches with relying on irrelevant expertise.
Each argument represents a distinct, classic logical fallacy. The Dr. Smith argument is an ad hominem attack. The movie argument is circular reasoning. The lucky socks argument is a correlation-to-causation error. The actor argument is an appeal to inappropriate authority.

Step-by-Step Solution

1
Analyze the first argument regarding Dr. Smith.
Identify that the argument attacks Dr. Smith's professional record rather than his medical or dietary claims.
This helps match it to the description of a personal attack rather than addressing the substance of the argument.
2
Analyze the second argument regarding the sci-fi movie.
Identify that being the most popular and everyone going to see it mean the exact same thing.
This confirms the argument is circular, matching the description of assuming the conclusion in the premise.
3
Analyze the third argument regarding the lucky socks.
Identify that a causal relationship is drawn from a mere coincidence.
This corresponds to the flaw of assuming causation based on events occurring together.
4
Analyze the fourth argument regarding the tax policy.
Identify that an actor is being cited as an authority on an unrelated topic.
This matches the flaw of relying on an expert whose expertise is outside the relevant domain.

Key Concept

Identifying Common Logical Flaws
Question 70Question →

Urban Planner: To decrease traffic congestion in the downtown commercial district, the city plans to implement a new daily toll for any private vehicle entering the district during peak commuting hours. The city anticipates that this policy will successfully reduce the number of private vehicles entering the district. Clearly, this toll will achieve its goal of significantly reducing overall traffic congestion in the downtown commercial district.

Which one of the following is an assumption on which the urban planner's argument depends?

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Answer: The anticipated decrease in the number of private vehicles will not be accompanied by a corresponding increase in the number of commercial or public vehicles entering the downtown commercial district.

Answer

The argument depends on the assumption that the anticipated decrease in private vehicles will not be offset by a corresponding increase in other types of vehicles.
This statement is logically required by the argument. The argument concludes that overall traffic congestion will decrease based solely on the premise that private vehicle traffic will decrease. For this conclusion to hold, it must be true that other forms of traffic (like commercial or public vehicles) do not increase enough to offset the reduction in private vehicles. If they did, overall congestion would not decrease.

Step-by-Step Solution

1
Identify the main conclusion of the argument.
The conclusion is that the daily toll will significantly reduce overall traffic congestion in the downtown commercial district.
Understanding the exact scope of the conclusion is the first step in evaluating any logical argument.
2
Identify the supporting premise.
The premise is that the toll policy will successfully reduce the number of private vehicles entering the district.
We must determine what evidence the author uses to justify the conclusion.
3
Find the logical gap between the premise and the conclusion.
The argument shifts from a reduction in one specific type of vehicle (private) to a reduction in 'overall' traffic congestion. This ignores the possibility that other types of traffic might fill the void.
Necessary assumptions often bridge a gap between the specific terms in the premises and the broader terms in the conclusion.
4
Apply the Negation Test to the suspected necessary assumption.
Negating the correct statement yields: 'The decrease in private vehicles WILL be accompanied by a corresponding increase in commercial or public vehicles.' This negated statement destroys the conclusion because overall traffic would not decrease.
The Negation Test is the definitive way to prove whether a statement is strictly necessary for an argument to logically hold.

Key Concept

Necessary assumptions must be logically required for the conclusion to be true; often they defend the argument against alternative possibilities that would prevent the premise from leading to the conclusion.
Question 71Question →

Agronomist: The crop yields of farms in the Delta region have increased by 20 percent since a new soil-aeration technique was introduced three years ago. The developer of this technique claims that it improves nutrient absorption, directly causing the surge in yields. However, this claim is incorrect; the true cause of the increased yields is the unusually favorable rainfall pattern the Delta region has experienced over the same three-year period.

Which of the following, if true, provides the strongest evidence to support the agronomist's conclusion?

Show answer & explanation

Answer: Farms in the neighboring Echo region, which experienced the exact same favorable rainfall patterns but did not adopt the new soil-aeration technique, also saw a 20 percent increase in crop yields over the last three years.

Answer

The correct answer is the option stating that farms in the neighboring Echo region experienced the exact same favorable rainfall patterns but did not adopt the new soil-aeration technique, and still saw a 20 percent increase in crop yields.
The agronomist claims that favorable rainfall, rather than a newly introduced soil-aeration technique, caused a 20 percent increase in crop yields. This is a classic causal argument where two potential causes occurred at the same time. The correct answer provides a perfect control scenario: a neighboring region that experienced the exact same rainfall but did NOT use the new technique. Because this control region also experienced the identical 20 percent yield increase, it strongly supports the conclusion that the rainfall alone is sufficient to cause the surge, effectively isolating it as the true variable.

Step-by-Step Solution

1
Identify the main conclusion and the premises of the argument.
The main conclusion is that unusually favorable rainfall caused the 20 percent increase in crop yields. The premises are that yields increased after the introduction of a new aeration technique, but favorable rainfall also occurred concurrently.
Evaluating an argument requires a precise understanding of the causal claim the author is attempting to prove.
2
Analyze the logical gap in the agronomist's reasoning.
The agronomist asserts that rainfall, rather than the aeration technique, caused the yield increase, but provides no evidence to definitively separate the effects of these two simultaneous variables.
Identifying the missing link allows you to determine what specific evidence is needed to strengthen the argument.
3
Evaluate the options to find one that isolates the agronomist's proposed cause.
The correct option demonstrates that in a comparable region where only the rainfall occurred (without the aeration technique), the exact same yield increase resulted.
In causal reasoning, showing a 'cause without effect' or an 'effect without the rival cause' (a control group) is the most robust way to strengthen a specific causal hypothesis.

Key Concept

Strengthening Causal Arguments via Control Groups
Estimated Time:1m 45s
Question 72Question →

Philosopher: A political doctrine cannot be considered genuinely egalitarian unless it categorically repudiates the concept of inherited executive authority, except in systems where the exercise of such authority is entirely symbolic. The foundational charters of the Valesian Order establish a governance model predicated on inherited executive authority. Consequently, the Valesian charters fail to offer a genuinely egalitarian political doctrine.

Which one of the following, if assumed, enables the philosopher's conclusion to be properly drawn?

Show answer & explanation

Answer: No governance model predicated on inherited executive authority restricts the exercise of that authority to entirely symbolic functions.

Answer

The correct assumption is that no governance model predicated on inherited executive authority restricts the exercise of that authority to entirely symbolic functions.
The philosopher's rule states that to be genuinely egalitarian, a doctrine must EITHER repudiate inherited authority OR possess authority that is entirely symbolic. The Valesian charters do not repudiate inherited authority. Therefore, to validly conclude that they are definitively not egalitarian, we must assume they also fail the second condition (i.e., their authority is not entirely symbolic). The correct statement provides a universal rule that any model with inherited authority (which the Valesian charters have) inherently fails to be entirely symbolic. This closes the logical gap and forces the conclusion to be 100% true.

Step-by-Step Solution

1
Map the formal logic of the philosopher's primary principle.
Genuinely Egalitarian -> Repudiates Inherited Authority OR Authority is Entirely Symbolic.
The phrase 'cannot be... unless... except when' creates a compound necessary condition. A doctrine must meet at least one of those two conditions to be considered egalitarian.
2
Analyze the application of the principle to the Valesian Order.
The Valesian charters establish inherited authority, meaning they fail the 'Repudiates Inherited Authority' condition.
The stimulus states the charters are 'predicated on inherited executive authority.'
3
Identify the logical gap leading to the conclusion.
The author concludes the charters are NOT egalitarian. For this to be definitively true, the charters must also fail the second necessary condition: their authority must NOT be entirely symbolic.
If the Valesian authority were entirely symbolic, it could still theoretically be egalitarian under the philosopher's rule. We must eliminate this possibility to guarantee the conclusion.
4
Evaluate the correct assumption.
The statement 'No governance model predicated on inherited executive authority restricts... to entirely symbolic functions' translates to: Inherited Authority -> NOT Entirely Symbolic.
Because the Valesian charters have inherited authority, this assumption guarantees their authority is not entirely symbolic, failing both necessary conditions and strictly proving they are not egalitarian.

Key Concept

Sufficient Assumptions with Compound Necessary Conditions
Question 73Question →

Match each flawed argument stimulus to the abstract description that most accurately identifies its reasoning error.

Click a left item, then click its matching right item

Items

Sociologist: A comprehensive ten-year study reveals that neighborhoods featuring numerous public parks consistently exhibit the highest levels of civic engagement. Therefore, city planners can directly foster community participation by investing in the construction of new green spaces.
Business Analyst: Any corporation that successfully dominates its market sector possesses a highly adaptable executive board. Given that the leadership at OmniCorp has demonstrated extraordinary flexibility during recent industry shifts, the company is virtually guaranteed to achieve market dominance.
Administrator: Critics allege that our institution is admitting a smaller total number of local residents than we did in the past. This is demonstrably false. Our internal records clearly show that local residents now comprise 35 percent of the incoming freshman class, a significant increase from just 22 percent five years ago.
Ethicist: Some critics argue that the corporation's aggressive takeover strategy is deeply unfair to small competitors. However, fairness essentially means playing by the rules of the game. Since the corporation has meticulously followed every financial regulation and broken no laws, its strategy must be considered entirely fair.

Matches

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Answer

The Sociologist's argument demonstrates a correlation-causation flaw. The Business Analyst's argument demonstrates a necessary vs. sufficient flaw. The Administrator's argument demonstrates a percentage vs. number flaw. The Ethicist's argument demonstrates an equivocation flaw.
Each argument commits a classic logical fallacy. The Sociologist infers causation from correlation. The Business Analyst treats a necessary condition as a sufficient condition. The Administrator attempts to refute a claim about raw numbers using only percentage data. The Ethicist shifts the meaning of 'fairness' from an ethical standard to a strictly legal one.

Step-by-Step Solution

1
Analyze the Sociologist's argument to identify its logical gap.
The premise establishes a correlation between parks and engagement, while the conclusion claims parks directly cause the engagement.
Identifying the leap from association to causation reveals the structural error.
2
Examine the Business Analyst's conditional reasoning regarding market dominance.
The argument establishes an adaptable board as a requirement, but concludes that it guarantees dominance.
Recognizing the illegal reversal isolates the necessary vs. sufficient fallacy.
3
Evaluate the metrics used in the Administrator's defense.
The critics discuss a total number (absolute magnitude), while the Administrator's counter-evidence only cites a percentage (fractional share).
Contrasting the units of measurement highlights the percentage vs. number flaw.
4
Deconstruct the Ethicist's argument about corporate fairness.
The critics use 'unfair' as a moral evaluation, while the Ethicist redefines 'fairness' as mere procedural legality.
Tracking the changing definition of the core concept exposes the equivocation.

Key Concept

Logical Reasoning: Flaw in the Reasoning
Question 74Question →

Review the following excerpts drawn from various public statements and reports. Identify the underlying logical error in each argument by pairing it with its most precise methodological description.

Click a left item, then click its matching right item

Items

Civic Planner: A thriving metropolitan ecosystem fundamentally relies upon robust public infrastructure and an equitable taxation model. Since the newly elected administration has successfully modernized the city’s public infrastructure and implemented a progressive taxation model, a thriving metropolitan ecosystem will inevitably materialize.
Financial Analyst: The corporation's expansion into hardware has successfully generated more new revenue dollars than its core software business. After all, the hardware division's revenue grew by an impressive 65 percent this past fiscal year, whereas the software division's revenue grew by only 12 percent. This disparity clearly proves that the hardware division generated a greater absolute increase in revenue.
Constitutional Scholar: The charter explicitly protects the right of all citizens to freely exercise their deeply held religious and personal beliefs. Since maintaining peak physical fitness is a deeply held personal belief for many citizens, it is unconstitutional for the municipal government to restrict the hours that people can exercise at local gymnasiums.
Agronomist: The pervasive systemic necrosis affecting the region's tomato yield is undoubtedly driven by the recent proliferation of the Lygus bug. Comprehensive surveys demonstrate that agricultural sectors with the densest Lygus infestations invariably present the most advanced stages of necrosis, while pesticide-treated sectors devoid of the insects remain completely healthy.

Matches

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Answer

The Civic Planner matches the necessary-vs-sufficient flaw. The Financial Analyst matches the percentage-vs-absolute flaw. The Constitutional Scholar matches the equivocation flaw. The Agronomist matches the correlation-causation flaw.
Each stimulus exhibits a classic logical vulnerability. The Civic Planner commits a conditional logic error by confusing necessary requirements with sufficient guarantees. The Financial Analyst commits a mathematical reasoning error by substituting relative rate changes for absolute numerical shifts. The Constitutional Scholar commits a semantic error by equivocating on the dual meanings of the word 'exercise'. The Agronomist commits a causal error by assuming that a high degree of correlation between two localized phenomena proves a one-way causal relationship.

Step-by-Step Solution

1
Analyze the Civic Planner's argument to identify its structural flaw.
The argument assumes that meeting required conditions guarantees success, which is confusing a necessary condition for a sufficient one.
This directly aligns with the description of treating required conditions as sufficient.
2
Evaluate the Financial Analyst's reasoning regarding revenue growth.
The argument uses percentage growth figures to make definitive claims about absolute dollar amounts, which is mathematically invalid without knowing the starting values.
This matches the description concerning comparative absolute quantities versus percentage changes.
3
Examine the Constitutional Scholar's application of the term 'exercise'.
The scholar shifts from discussing the 'exercise' of a legal right to physical 'exercise' at a gymnasium.
This is a classic equivocation fallacy, matching the description of trading on an ambiguity.
4
Assess the Agronomist's conclusion about the cause of necrosis.
The agronomist uses a strong co-occurrence (correlation) between the bugs and the disease to conclude that the bugs cause the disease.
This represents a failure to distinguish between correlation and causation.

Key Concept

Evaluating flawed reasoning across multiple argument structures, including causal, quantitative, formal logic, and linguistic errors.
Question 75Question →

Archaeologist: Every major ancient civilization that collapsed due to a prolonged drought left behind distinct geological markers in the soil sediment of their central water reservoirs. Recent excavations at the central reservoir of the ancient city of Olaria have revealed these exact geological markers in the soil sediment. Therefore, the collapse of the Olarian civilization must have been caused by a prolonged drought.

Which of the following most accurately describes the flaw in the archaeologist's reasoning?

Show answer & explanation

Answer: It treats a condition that is necessary for a certain event to have occurred as a condition that is sufficient to guarantee that the event occurred.

Answer

The correct answer is the option stating that the argument treats a necessary condition as a sufficient condition.
The argument's first premise establishes a conditional relationship: if a civilization collapses due to drought, it must leave distinct geological markers. Leaving markers is therefore a necessary condition of a drought collapse. The author observes that Olaria met this necessary condition (the markers were found) and concludes that the sufficient condition (a drought collapse) must have occurred. Other events could potentially cause these exact same markers, so finding them does not guarantee a drought was the cause.

Step-by-Step Solution

1
Map the logical structure of the argument's premises and conclusion.
Premise 1: If an ancient civilization collapsed due to drought (A), then it left distinct geological markers (B). Premise 2: Olaria left distinct geological markers (B). Conclusion: Therefore, Olaria collapsed due to drought (A).
Deconstructing the argument into formal logic reveals its underlying mechanics and makes structural flaws apparent.
2
Identify the logical flaw committed in the argument's structure.
The argument commits the formal fallacy of affirming the consequent (A -> B, B, therefore A).
The author takes a condition that is guaranteed to follow from an event (a necessary condition) and assumes its presence guarantees the event happened (a sufficient condition).
3
Evaluate the answer choices to find the abstract description that matches this specific flaw.
The option describing the confusion between a necessary condition and a sufficient condition perfectly matches the structural error identified in Step 2.
LSAT flaw questions often describe formal conditional logic errors in terms of confusing necessary and sufficient conditions.

Key Concept

Identifying Conditional Logic Flaws (Illegal Reversal / Affirming the Consequent)
Question 76Question →

Match each institutional decision-making scenario with the universal principle that, if assumed to be true, most helps to justify its conclusion.

Click a left item, then click its matching right item

Items

A hospital board decides to fund research into a rare genetic disease rather than a common lifestyle-induced disease, even though both research programs cost the same. The board concludes this funding decision is morally correct.
A corporation chooses to award its limited bonus pool to a department that achieved its goals despite unforeseen supply chain failures, rather than a department that achieved its goals under normal conditions. The executive team concludes this distribution is equitable.
A judge imposes a lighter sentence on a defendant who embezzled funds to pay for emergency medical bills than on a defendant who embezzled the same amount for personal enrichment. The judge reasons that this disparity in sentencing is just.
A city council forgives the late tax penalties of a business that was forcibly closed by a natural disaster, while enforcing the penalties against a business that simply forgot to file. The council determines this disparate treatment is fair.

Matches

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Answer

Scenario 1 pairs with the principle prioritizing resources for no-fault conditions. Scenario 2 pairs with the principle favoring rewards for overcoming external obstacles. Scenario 3 pairs with the principle allowing sanction disparities for existential necessity. Scenario 4 pairs with the principle allowing waivers for noncompliance caused by external catastrophes.
Each correct pairing successfully matches a scenario containing a logical gap between its factual premises and its normative conclusion with a universal conditional principle that serves as a sufficient premise to bridge that exact gap.

Step-by-Step Solution

1
Analyze the conclusion and the supporting premises for the first scenario.
The conclusion asserts the moral correctness of funding genetic disease research over lifestyle-induced disease research. The premises distinguish the diseases by their causes: unpreventable versus voluntary.
Identifying the logical gap between the factual premises and the normative conclusion is required to find the bridging principle.
2
Select the principle that logically guarantees the conclusion for the first scenario.
The principle stating that an institution acts morally when directing resources to address conditions arising through no fault of the affected parties perfectly bridges the gap.
This principle acts as a sufficient premise that strictly entails the moral correctness of the board's decision.
3
Examine the second scenario to identify its core normative claim.
The conclusion is that awarding bonuses to the department facing supply chain failures is equitable, justified by the presence of unforeseen external difficulties.
To formally justify an equitable distribution, a principle must explicitly validate overcoming unforeseen difficulties as a sufficient condition for equity.
4
Select the principle that justifies the second scenario's conclusion.
The principle asserting that a reward distribution is equitable if it favors those who succeed despite unpredictable external obstacles provides the necessary logical bridge.
It explicitly connects the factual condition (unforeseen failures) to the normative judgment (equitable distribution).
5
Analyze the third scenario's judicial decision.
The judge concludes the disparate sentencing is just because one crime was motivated by emergency medical bills (necessity) and the other by personal enrichment.
The appropriate principle must establish that a disparity in sentencing is just if motivated by such necessity.
6
Select the principle justifying the third scenario.
The principle stating that a disparity in sanction severity is just if the lighter sanction is imposed for an offense motivated by existential necessity secures the judge's reasoning.
Emergency medical bills represent existential necessity, fulfilling the sufficient condition established by the principle.
7
Analyze the fourth scenario's administrative decision.
The council concludes it is fair to forgive tax penalties for a business closed by a natural disaster, but not for one that simply forgot to file.
The justifying principle must permit waiving penalties as fair specifically when noncompliance is due to uncontrollable external events.
8
Select the corresponding principle for the fourth scenario.
The principle stating it is fair to waive punitive measures if noncompliance was caused by an unavoidable external catastrophe completes the argument.
A natural disaster perfectly aligns with the concept of an unavoidable external catastrophe, triggering the sufficient condition for fairness.

Key Concept

Identifying sufficient bridging principles that logically connect factual premises to normative or declarative conclusions.
Question 77Question →

Match each argument with the piece of new evidence that most effectively weakens its conclusion. Assume all evidence statements are true.

Click a left item, then click its matching right item

Items

Excavations at the ancient site of Kaelen yielded hundreds of bronze swords but no bronze agricultural tools. Historians conclude that the Kaelen people were primarily a warrior society that did not engage in farming.
In the year following the introduction of a premium loyalty program, a supermarket chain saw its total sales volume increase by 15%. Executives concluded that the new program successfully attracted a broader customer base.
One year after a corporate wellness initiative mandated ergonomic chairs, employee reports of chronic back pain rose by 25%. Management concluded that the new ergonomic chairs must be physically harmful.
A municipality deemed its recycling campaign a failure, noting that the percentage of total municipal waste successfully recycled fell from 30% to 22% over the campaign's duration. They concluded residents are recycling a smaller absolute amount of material.

Matches

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Answer

Argument 1 matches with the soil composition evidence. Argument 2 matches with the bankrupt competitors evidence. Argument 3 matches with the digital portal evidence. Argument 4 matches with the commercial waste expansion evidence.
Each correct pairing directly attacks the specific logical vulnerability in the argument's inferential leap without contradicting the stated premises. The soil preservation bias explains the missing tools; the closed competitors provide an alternate cause for the sales bump; the new portal explains the increased reports independently of actual pain; and the massive increase in total waste demonstrates how the recycling percentage could drop while the absolute amount recycled remained constant or increased.

Step-by-Step Solution

1
Analyze Argument 1 (Kaelen excavations)
Identify the flaw: concluding a lack of activity from an absence of evidence in the archaeological record.
Finding an alternative explanation for why the tools didn't survive perfectly attacks this gap.
2
Analyze Argument 2 (Supermarket loyalty program)
Identify the flaw: Correlation vs. Causation. The argument assumes the program caused the sales increase.
Finding an alternate cause for the sales bump (competitors closing) severs the causal link.
3
Analyze Argument 3 (Ergonomic chairs)
Identify the flaw: confusing an increase in reports of a problem with an increase in the actual incidence of the problem.
Evidence showing that reporting became easier explains the rise in reports without validating the chairs' harm.
4
Analyze Argument 4 (Recycling percentages)
Identify the flaw: Percentage vs. Number. A drop in percentage does not guarantee a drop in the absolute amount if the overall total increased.
Evidence showing the total waste denominator artificially inflated proves the absolute amount of recycling didn't necessarily drop.
5
Evaluate the remaining distractor evidence
Identify that the evidence regarding auditor data errors attacks the premises directly.
In standard logical reasoning evaluation, effectively weakening an argument requires accepting the premises as true and attacking the inferential leap, making this a classic trap.

Key Concept

Identifying and exploiting specific logical gaps (Alternative Explanations, Causal Flaws, Reporting Bias, and Percentage vs. Number errors) to undermine an argument's conclusion.
Question 78Question →

Match each brief argument with the specific piece of new evidence that most effectively weakens its conclusion.

Click a left item, then click its matching right item

Items

A university study found that students who take notes by hand score higher on exams than those who type. Thus, handwriting notes causes better academic performance.
After the regional government introduced a subsidy for solar panels, carbon emissions dropped by 15%. This proves the subsidy was highly effective.
A poll at a tech industry conference revealed that 85% of attendees believe AI will create jobs. Therefore, the general public is optimistic about AI.
Over the last five years, workplace accidents involving robotic arms have tripled, while accidents involving human workers decreased. Clearly, robotic arms are becoming less safe.

Matches

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Answer

Argument 1 matches Evidence C. Argument 2 matches Evidence A. Argument 3 matches Evidence D. Argument 4 matches Evidence B.
Each correct pairing effectively targets the specific logical vulnerability in the corresponding argument: Argument 1 is weakened by an alternate cause for a correlation; Argument 2 is weakened by an independent alternate cause for an outcome; Argument 3 is weakened by exposing sample bias; and Argument 4 is weakened by providing context on population size changes (base rate).

Step-by-Step Solution

1
Analyze Argument 1 (Note-taking)
Identified a correlation-to-causation flaw. Look for evidence providing an alternate explanation for the correlation.
Evidence C shows that the motivation level of the students is the true cause of the higher scores, not the physical act of note-taking.
2
Analyze Argument 2 (Solar subsidy)
Identified a chronological correlation assumed to be causal. Look for an alternate cause for the emissions drop.
Evidence A provides a strong alternate cause: a decline in manufacturing due to a recession, weakening the claim that the subsidy was responsible.
3
Analyze Argument 3 (AI poll)
Identified a sampling flaw. The sample (tech attendees) is not representative of the conclusion's target group (the general public).
Evidence D highlights why this specific sample is inherently biased compared to the general public, destroying the argument's validity.
4
Analyze Argument 4 (Robotic accidents)
Identified a numbers vs. proportions flaw. An absolute increase in accidents doesn't mean safety decreased if usage also increased massively.
Evidence B shows the number of robots increased drastically, which naturally leads to more total accidents even if the rate of accidents per robot remained safe or improved.

Key Concept

Identifying and targeting specific logical vulnerabilities (causation errors, unrepresentative samples, and base rate neglect) to weaken arguments.
Question 79Question →

Safety Inspector: The factory management claims that they prioritize a culture of safety above all else. Yet, their recent decision to aggressively expand into volatile international markets is widely considered by industry analysts to be a highly risky move. Therefore, the management's claim regarding their prioritization is clearly false.

Statement: The safety inspector's argument is logically flawed because it relies on shifting the meaning of a key concept during the course of the reasoning.

Show answer & explanation

Answer: True

Answer

True
The safety inspector's argument commits a classic fallacy of equivocation. It takes the management's stated commitment to a 'culture of safety' (implying workplace and physical safety) and attempts to disprove it by citing a 'highly risky' financial and strategic business expansion. Financial risk and physical safety are distinct concepts. By treating them as opposites in the same context, the argument impermissibly shifts the meaning of the concept, making the given statement true.

Step-by-Step Solution

1
Analyze the premises and conclusion of the argument.
Premise: Management made a 'highly risky' business expansion. Conclusion: Management's claim about prioritizing a 'culture of safety' is false.
Identifying the core structure of the argument isolates how the evidence is used to support the conclusion.
2
Examine the relationship between the key terms in the premise and the conclusion.
The argument uses the presence of financial 'risk' to disprove a commitment to physical 'safety'.
Many logical flaws occur when the language connecting the premises to the conclusion is mismatched or assumes unstated equivalencies.
3
Evaluate whether the provided statement accurately describes this logical disconnect.
The statement identifies 'shifting the meaning of a key concept'. This perfectly describes the error of conflating financial risk with physical danger.
Determining the truth value requires matching the abstract description of the flaw in the statement to the specific error committed in the stimulus.

Key Concept

Flaw in the Reasoning: Equivocation
Question 80Question →

For each argumentative claim presented on the left, identify the factual statement on the right that most severely undermines its conclusion.

Click a left item, then click its matching right item

Items

An analysis of regional healthcare data indicates that patients recovering from joint surgery at Apex Clinic have shorter hospital stays than those at Zenith Hospital. Thus, Apex Clinic's surgical techniques must be superior.
Following the enactment of a municipal recycling mandate, the volume of refuse processed at the county incinerator dropped by twenty percent. It is evident that the mandate successfully minimized the amount of garbage residents generate.
Archaeological digs at the ancient city of Oakhaven revealed that grain storage silos built in the twelfth century are substantially smaller than those built in the tenth century. This suggests that Oakhaven's agricultural output declined over those two centuries.
Over the last quarter, the local bookstore 'Folio & Spine' saw a sharp increase in revenue immediately after they began hosting weekly author readings. Therefore, the author readings are driving the bookstore's financial success.

Matches

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Answer

The Apex Clinic argument matches with the admission policy statement; the recycling mandate argument matches with the manufacturing plant closure; the Oakhaven silos argument matches with the denser storage techniques; and the bookstore argument matches with the closure of the competing retailer.
Each correct match successfully targets the logical gap in the respective argument. The healthcare argument suffers from a flawed comparison (selection bias), which is exposed by the clinic's admission policy. The recycling argument shifts scope from total refuse to residential garbage, which is undermined by the factory closure. The archaeological argument assumes a direct volume-to-yield ratio, which is weakened by the denser storage fact. The bookstore argument commits a post hoc fallacy, which is undermined by the closure of a competitor providing an alternate cause for increased revenue.

Step-by-Step Solution

1
Analyze the healthcare argument.
Identified the conclusion (surgical techniques are superior) and the premise (shorter hospital stays).
To weaken the argument, we must find a statement showing the patient populations differ in a way that affects recovery times, which points to the admission policy statement.
2
Analyze the municipal recycling argument.
Identified the conclusion (mandate minimized resident garbage) based on the premise (a 20% total drop at the incinerator).
To weaken, we need an alternate source for the total drop that has nothing to do with residents, pointing to the closure of the manufacturing plant.
3
Analyze the archaeological argument about silos.
Identified the conclusion (agricultural output declined) based on the premise (silos are smaller).
To weaken, we must find a reason why silos would be smaller even if agricultural yield remained steady, pointing to the denser storage techniques.
4
Analyze the bookstore revenue argument.
Identified the causal claim (author readings drive success) based on temporal correlation.
To weaken a causal claim based on correlation, we must find an alternate cause for the revenue increase, pointing to the closure of the competitor.

Key Concept

Identifying unstated assumptions and evaluating alternative explanations to weaken causal or comparative arguments.
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Argument Evaluation Practice Questions — LSAT — Page 4 | Examkin