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Parallel Reasoning

98 questions

All types98Multiple choice55Multiple select4True / False5Matching34
Question 21Question →

Chef: To bake a flawless soufflé, a baker must use room-temperature eggs and precisely fold the egg whites into the batter. Marcus precisely folded the egg whites into his batter. Therefore, if Marcus fails to bake a flawless soufflé, it must be because he did not use room-temperature eggs.

Which one of the following arguments exhibits a flawed pattern of reasoning most similar to that in the chef's argument?

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Answer: Botanist: For a desert orchid to bloom, it must receive ample direct sunlight and be planted in well-draining soil. This particular desert orchid is planted in well-draining soil. Hence, if it fails to bloom, it must be because it is not receiving ample direct sunlight.

Answer

The argument about the botanist and the desert orchid exhibits the exact same flawed pattern of reasoning.
The correct answer exactly mirrors the highly specific, flawed logical structure of the stimulus. The stimulus establishes two necessary conditions for a goal (room-temperature eggs and precise folding for a flawless soufflé). It then states that one condition is met, and concludes that if the goal fails, it must be due to the absence of the other stated condition. This is flawed because it ignores the possibility of other unstated necessary conditions causing the failure (e.g., wrong oven temperature). Similarly, the correct answer establishes two necessary conditions for a goal (sunlight and well-draining soil for an orchid to bloom). It states that one condition is met (soil), and falsely concludes that if the goal fails (no bloom), it must be due to the absence of the other stated condition (sunlight), ignoring other possible causes for failure.

Step-by-Step Solution

1
Analyze the logical structure of the stimulus argument.
Structure: Goal (flawless soufflé) -> Necessary Condition 1 (room-temp eggs) AND Necessary Condition 2 (precisely fold).
Identifying the formal conditional logic is the first step in parallel reasoning.
2
Identify how the premises are applied to the specific case in the stimulus.
The argument states that Marcus met Necessary Condition 2 (precisely folded).
We must map the specific scenario to the abstract structure.
3
Analyze the conclusion to identify the exact logical flaw.
Conclusion: If Goal fails (Not Goal), it must be because of Not Necessary Condition 1. The flaw is assuming the stated necessary conditions are exhaustive. The soufflé could fail for an unstated reason (e.g., incorrect oven temperature) despite having room-temperature eggs.
Understanding the precise nature of the error is required to find its parallel.
4
Evaluate the answer choices for an identical structure.
The correct option states: Goal (bloom) -> N1 (sunlight) AND N2 (soil). Has N2 (soil). Concludes: If Not Goal, then Not N1. This is a perfect structural match.
The correct answer must match both the conditional premise structure and the exact flawed application in the conclusion.

Key Concept

Parallel Flaw - Assuming Stated Necessary Conditions are Exhaustive
Question 22Question →

If a startup company secures venture capital funding, it will rapidly expand its operations. The tech startup Zephyr Innovations did not secure venture capital funding. Therefore, Zephyr Innovations will not rapidly expand its operations.

Which of the following arguments exhibits a flawed pattern of reasoning most similar to the one exhibited in the argument above?

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Answer: If a museum acquires a highly anticipated exhibit, its daily visitor numbers will increase. The city art museum did not acquire a highly anticipated exhibit. Thus, its daily visitor numbers will not increase.

Answer

The argument concluding that the city art museum's visitor numbers will not increase because it did not acquire a highly anticipated exhibit.
The stimulus argument commits the fallacy of illegal negation (denying the antecedent). It establishes a conditional relationship (If A, then B), states that the sufficient condition (A) did not occur, and wrongly concludes that the necessary condition (B) cannot occur. The correct answer follows this exact flawed structure: it establishes that acquiring an exhibit leads to increased visitors, notes that the museum did not acquire an exhibit, and improperly concludes that visitors will not increase.

Step-by-Step Solution

1
Map the logical structure of the stimulus argument.
Premise 1: If Venture Capital (VC) -> Rapid Expansion (RE). Premise 2: Not VC. Conclusion: Therefore, Not RE.
Identifying the formal structure is necessary to pinpoint the exact logical flaw.
2
Identify the type of logical flaw committed in the stimulus.
The argument commits an illegal negation (denying the antecedent). It assumes that if the sufficient condition fails, the necessary condition must also fail.
Parallel flaw questions require matching the specific abstract type of erroneous reasoning.
3
Evaluate the answer choices to find the one with the identical flawed structure.
The museum argument matches exactly: Premise 1: If Acquire Exhibit (AE) -> Increase Visitors (IV). Premise 2: Not AE. Conclusion: Therefore, Not IV.
The correct answer must replicate the abstract structure of the original flaw, regardless of the subject matter.

Key Concept

Parallel Flaw: Illegal Negation
Question 23Question →

Most architects working in the modernist tradition deliberately avoid ornamentation. Furthermore, most architects working in the modernist tradition prioritize functional spatial layouts. It follows logically that at least some architects who avoid ornamentation prioritize functional spatial layouts.

The pattern of reasoning in the argument above is most logically similar to that in which one of the following?

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Answer: Most classical symphonies heavily feature a string section. Additionally, most classical symphonies are divided into four distinct movements. Consequently, some classical symphonies that heavily feature a string section are divided into four distinct movements.

Answer

The argument about classical symphonies heavily featuring a string section and being divided into four movements.
The correct answer accurately replicates the 'Most + Most = Some' logical structure of the stimulus. It assigns two majority traits to a single subject (classical symphonies), and validly deduces that because both traits apply to more than half of the subject, there must be an overlap where at least some entities possess both traits.

Step-by-Step Solution

1
Analyze the logical structure of the stimulus argument.
Premise 1: Most A (modernist architects) are B (avoid ornamentation). Premise 2: Most A (modernist architects) are C (prioritize functional layouts). Conclusion: Therefore, some B are C.
Identifying the formal abstract pattern of the argument is required before finding its parallel.
2
Determine the validity of the stimulus argument.
The argument is logically valid. Because 'most' means more than half, if more than half of A are B, and more than half of A are C, those two majority subgroups must mathematically intersect, guaranteeing that at least some B are C.
A parallel argument must match not just the quantifier distribution, but also the logical validity of the original argument.
3
Evaluate the answer choices to find the exact structural match (Most A are B; Most A are C; therefore, Some B are C).
The option concerning classical symphonies matches this structure precisely: Most A (symphonies) are B (string section); Most A (symphonies) are C (four movements); therefore, Some B are C.
Only one option will maintain the exact premise-to-conclusion logical flow and quantifier strength.

Key Concept

Parallel Quantifier Logic
Question 24Question →

Any fossilized skeleton classified as a Spinosaurid must exhibit elongated neural spines. In turn, any fossilized skeleton exhibiting elongated neural spines belonged to an animal adapted to a semi-aquatic environment. Thus, if a fossilized skeleton did not belong to an animal adapted to a semi-aquatic environment, it cannot be classified as a Spinosaurid.

Which one of the following arguments exhibits a logical structure most similar to that of the argument above?

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Answer: Any painting definitively attributed to the anonymous Venetian master must feature genuine lapis lazuli pigment. Furthermore, any painting featuring genuine lapis lazuli pigment was created after the Eastern trade routes were established. Consequently, if a painting was not created after the Eastern trade routes were established, it cannot be definitively attributed to the anonymous Venetian master.

Answer

The argument concerning the Venetian master's paintings accurately mirrors the logical structure of the stimulus.
The correct answer accurately mirrors the structural logic of the stimulus. It establishes a chain of necessary conditions (If A then B, if B then C) and concludes with the valid contrapositive of that entire chain (Therefore, if not C then not A). Both the quantifier strength ('Any/All') and modal certainty ('must/cannot') match perfectly.

Step-by-Step Solution

1
Deconstruct the stimulus argument into formal logic.
Premise 1: Spinosaurid (A) -> Elongated spines (B). Premise 2: Elongated spines (B) -> Semi-aquatic (C). Conclusion: Not semi-aquatic (~C) -> Not Spinosaurid (~A).
Mapping the argument helps identify the exact logical architecture (Chain of Conditionals leading to a Contrapositive).
2
Determine the validity of the stimulus.
The argument is structurally valid. A -> B and B -> C combines to form A -> C. The contrapositive of A -> C is ~C -> ~A, which matches the conclusion.
You must know if you are looking for a valid parallel structure or an invalid parallel structure.
3
Evaluate the options to find the identical valid structure, ignoring superficial subject matter.
The correct argument maps as: Venetian master (A) -> Lapis lazuli (B). Lapis lazuli (B) -> After Eastern trade routes (C). Conclusion: Not after Eastern trade routes (~C) -> Not Venetian master (~A).
The correct answer in a Parallel Reasoning question must strictly duplicate the deductive architecture and quantifier strength of the original text.

Key Concept

Parallel Valid Structure
Question 25Question →

Any soil treatment designed to maximize crop yield must contain high levels of nitrogen. However, no organic fertilizer contains high levels of nitrogen. Therefore, no organic fertilizer is designed to maximize crop yield.

Which one of the following arguments is most similar in its logical features to the argument above?

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Answer: Every properly drafted legal contract includes a severability clause. No document written by a layperson includes a severability clause. Hence, no document written by a layperson is a properly drafted legal contract.

Answer

The argument demonstrating that since every properly drafted legal contract includes a severability clause, and no document written by a layperson includes one, no document written by a layperson is properly drafted.
The correct answer perfectly replicates the formal logical structure of the stimulus. The stimulus argues: All A are B (Yield -> Nitrogen); No C is B (Organic -> ~Nitrogen); Therefore, no C is A (Organic -> ~Yield). The correct option identically reasons: All A are B (Properly drafted -> Severability); No C is B (Layperson -> ~Severability); Therefore, no C is A (Layperson -> ~Properly drafted). Both are valid applications of contrapositive reasoning using matching absolute quantifiers.

Step-by-Step Solution

1
Abstract the formal logic of the stimulus.
Premise 1: Maximize Yield (M) -> High Nitrogen (H). Premise 2: Organic (O) -> ~High Nitrogen (~H). Conclusion: Organic (O) -> ~Maximize Yield (~M).
Identifying the symbolic structure reveals a valid application of the contrapositive across a universal 'no' statement.
2
Summarize the argument's core pattern.
The pattern is: All A are B; No C is B; Therefore, No C is A.
This abstracted template serves as the blueprint for evaluating the answer choices.
3
Evaluate the answer choices against the established blueprint.
Only the option discussing legal contracts matches the template: Properly Drafted (A) -> Severability (B); Layperson (C) -> ~Severability (~B); Therefore, Layperson (C) -> ~Properly Drafted (~A).
Finding an exact structural match, including validity and quantifier strength, is required to correctly answer a parallel reasoning question.

Key Concept

Parallel Conditional Logic
Question 26Question →

If an architectural firm is to win the city's waterfront redevelopment contract, it must either incorporate extensive green spaces into its design or partner with a prominent local engineering company. However, a firm cannot partner with a prominent local engineering company unless it agrees to a profit-sharing model dictated by the city council. The Apex Architectural Group steadfastly refuses to agree to any profit-sharing model. Thus, if Apex is to win the waterfront redevelopment contract, it must incorporate extensive green spaces into its design.

Which one of the following arguments exhibits a pattern of reasoning most logically similar to that exhibited by the argument above?

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Answer: If a new drug is to be approved for treating the rare disease, it must either demonstrate unprecedented efficacy or have no severe side effects. A drug can have no severe side effects only if its active compound is synthesized at low temperatures. The experimental drug X-12 cannot be synthesized at low temperatures. Therefore, if X-12 is to be approved for treating the rare disease, it must demonstrate unprecedented efficacy.

Answer

The argument concerning the new drug approval perfectly parallels the logical structure of the architectural firm stimulus.
The correct answer perfectly mirrors the logical skeleton of the stimulus. Both arguments state a sufficient condition that requires at least one of two necessary conditions. They then establish a further necessary condition for one of the original disjuncts, demonstrate that a specific subject fails to meet this further condition, and validly conclude that if the subject fulfills the initial sufficient condition, it must satisfy the remaining necessary condition.

Step-by-Step Solution

1
Translate the stimulus into formal logic.
Win Contract (W) -> Green Spaces (G) OR Partner (P). Partner (P) -> Profit Sharing (S) (from 'cannot P unless S'). Apex: ~S. Therefore, Apex: ~P. Conclusion: For Apex, W -> G.
Identifying the precise conditional relationships and the valid chain of deductions is required to find an exact structural parallel.
2
Analyze the correct option's logical structure.
Approved (A) -> Efficacy (E) OR No Side Effects (N). No Side Effects (N) -> Low Temp (L) (from 'N only if L'). Drug X-12: ~L. Therefore, X-12: ~N. Conclusion: For X-12, A -> E.
Mapping the candidate argument demonstrates 1:1 structural isomorphism with the stimulus.
3
Evaluate the distractors for structural deviations.
The software argument concludes B -> A (illegal reversal). The novel argument concludes ~A -> ~B (illegal negation). The mayoral argument reaches an absolute rather than conditional conclusion. The athlete argument commits a necessary/sufficient flaw by affirming the consequent in the secondary premise.
Parallel reasoning requires exact logical equivalence; any formal flaw or mismatch in conclusion modality eliminates the option.

Key Concept

Parallel Conditional Logic
Question 27Question →

Any oil painting that is to be successfully restored must first be thoroughly cleaned. Furthermore, an oil painting can be thoroughly cleaned only if its original varnish is completely dissolved. The original varnish on the newly discovered portrait cannot be completely dissolved. Therefore, the newly discovered portrait cannot be successfully restored.

Which one of the following arguments exhibits a pattern of reasoning most similar to that exhibited by the argument above?

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Answer: A commercial development project can be approved by the city council only if it passes an environmental impact review. Any project that passes an environmental impact review must include a comprehensive traffic management plan. The proposed shopping plaza does not include a comprehensive traffic management plan. Thus, the proposed shopping plaza cannot be approved by the city council.

Answer

The argument concerning the commercial development project and the traffic management plan.
The correct answer perfectly mirrors the valid deductive structure of the original stimulus. The stimulus establishes a chain of necessary conditions (Restored -> Cleaned -> Varnish Dissolved), introduces a specific case where the final necessary condition is unmet (~Varnish Dissolved), and validly concludes that the sufficient condition cannot occur (~Restored). The correct option establishes an identical chain (Approved -> Review -> Traffic Plan), introduces a case where the final necessary condition is unmet (~Traffic Plan), and validly concludes that the sufficient condition cannot occur (~Approved).

Step-by-Step Solution

1
Diagram the formal logical structure of the stimulus.
Restored -> Cleaned. Cleaned -> Varnish Dissolved. The portrait is NOT Varnish Dissolved. Conclusion: Therefore, the portrait is NOT Restored.
Mapping the conditional statements reveals the underlying skeleton of the argument: A -> B, B -> C. ~C. Therefore, ~A.
2
Identify the type and validity of the reasoning in the stimulus.
The argument is a valid application of chain conditional reasoning followed by modus tollens (denying the consequent). All premises use absolute certainty (any, must).
To find a parallel argument, the correct answer must also be fully valid, use the same logical mechanics, and match the absolute degree of certainty.
3
Evaluate the options to find the exact matching structure, regardless of subject matter.
The correct option diagrams as: Approved -> Environmental Review. Environmental Review -> Traffic Plan. The plaza is NOT Traffic Plan. Conclusion: Therefore, the plaza is NOT Approved.
This is a perfect structural duplicate of A -> B, B -> C, ~C, therefore ~A, maintaining absolute certainty throughout.

Key Concept

Parallel Valid Structure (Chain Conditionals and Modus Tollens)
Question 28Question →

Match each everyday argument to the formal valid deduction pattern that accurately describes its logical structure.

Click a left item, then click its matching right item

Items

If the city council approves the budget, the park will be renovated. The city council approved the budget. Therefore, the park will be renovated.
If the plant is a fern, it reproduces via spores. This plant does not reproduce via spores. Therefore, it is not a fern.
The suspect either fled to Canada or is hiding locally. The suspect did not flee to Canada. Therefore, the suspect is hiding locally.
If it rains, the soil gets wet. If the soil gets wet, the seeds will sprout. Therefore, if it rains, the seeds will sprout.

Matches

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Answer

Argument 1 matches Modus Ponens, Argument 2 matches Modus Tollens, Argument 3 matches Disjunctive Syllogism, and Argument 4 matches Hypothetical Syllogism.
Each everyday argument perfectly matches the formal structure of a standard deductive argument pattern, relying on established rules of logic to guarantee the truth of its conclusion.

Step-by-Step Solution

1
Analyze the first argument regarding the city council budget.
The structure is 'If A then B. A is true. Therefore B is true.'
This is the classic definition of Modus Ponens (Affirming the Antecedent).
2
Analyze the second argument regarding the fern reproducing.
The structure is 'If A then B. B is false. Therefore A is false.'
This is the classic definition of Modus Tollens (Denying the Consequent).
3
Analyze the third argument regarding the suspect fleeing.
The structure is 'Either A or B. A is false. Therefore B is true.'
This is the classic definition of Disjunctive Syllogism (Elimination).
4
Analyze the fourth argument regarding rain and seeds.
The structure is 'If A then B. If B then C. Therefore, If A then C.'
This is the classic definition of Hypothetical Syllogism (Chain Conditionals).

Key Concept

Identifying the formal structure of valid deductive arguments.
Question 29Question →

If a job applicant has a master's degree, they will be offered a second interview. Therefore, since Emily was offered a second interview, she must have a master's degree.

Which of the following contains a flawed pattern of reasoning most similar to that in the argument above?

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Answer: The old library must be historically significant. After all, if a building is historically significant, it will be protected by the city council, and the old library is indeed protected.

Answer

The option concluding that the old library must be historically significant because it is protected.
The correct answer perfectly replicates the illegal reversal flaw seen in the stimulus. The stimulus argues: If Master's (A) -> Interview (B). Emily got an Interview (B), therefore she has a Master's (A). The correct option argues: If Historically Significant (A) -> Protected (B). The library is Protected (B), therefore it is Historically Significant (A). Both erroneously confuse a necessary condition for a sufficient one.

Step-by-Step Solution

1
Analyze the logical structure and flaw of the stimulus.
The argument takes the conditional form: If A (has master's) then B (second interview). It states B is true (Emily offered a second interview), and concludes A is true (she has a master's).
Identifying the abstract structure is necessary to find a matching pattern.
2
Name the specific logical flaw.
The argument commits an illegal reversal. It treats a necessary condition (getting an interview) as if it were a sufficient condition to prove the original trigger (having a master's degree).
In parallel flaw questions, the correct answer must commit the exact same logical error.
3
Evaluate the options to find the identical structural flaw, ignoring the order of premises.
The option regarding the historically significant building takes the form: Conclusion A is true (it is historically significant) because if A then B (if historically significant, then protected), and B is true (it is protected).
This precisely matches the 'If A then B. B. Therefore A' illegal reversal structure of the original argument, despite the conclusion being stated first.

Key Concept

Parallel Flaw - Illegal Reversal
Question 30Question →

Match each flawed argument below to the abstract description that most accurately identifies its logical error.

Click a left item, then click its matching right item

Items

Anyone who gets the promotion will buy a new car. Therefore, since Sarah bought a new car, she must have gotten the promotion.
If the company increases its marketing budget, profits will rise. However, the company will not increase its marketing budget, so profits will certainly not rise.
The symphony orchestra is known worldwide for its flawless timing. Therefore, the orchestra's newly hired violinist must have flawless timing.
We should reject Dr. Smith's findings regarding the new food additive. After all, Dr. Smith was recently involved in a highly publicized tax evasion scandal.

Matches

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Answer

Argument 1 matches with treating a necessary condition as sufficient; Argument 2 matches with confusing the lack of a sufficient condition for the lack of a necessary condition; Argument 3 matches with the whole-to-part composition error; Argument 4 matches with the ad hominem source attack.
Each argument perfectly models one of the classic logical flaws tested on the LSAT: illegal reversal, illegal negation, composition (whole-to-part), and ad hominem. The corresponding abstract descriptions accurately summarize these precise structural errors without relying on the specific subject matter.

Step-by-Step Solution

1
Analyze the first argument's conditional structure.
Identify it as a conditional reasoning flaw where the necessary condition is used to incorrectly guarantee the sufficient condition.
To match it with the 'necessary treated as sufficient' description.
2
Analyze the second argument's conditional structure.
Identify it as a conditional reasoning flaw where the denial of the sufficient condition is incorrectly used to deny the necessary condition.
To match it with the 'sufficient condition not met' description.
3
Analyze the scope of the third argument.
Identify it as a composition flaw where an attribute of the orchestra is incorrectly applied to an individual member.
To match it with the 'characteristic of a group applied to a member' description.
4
Analyze the focus of the fourth argument.
Identify it as a source argument flaw where the author attacks the researcher instead of the research.
To match it with the 'dismissing a conclusion based on personal flaws' description.

Key Concept

Identifying abstract logical flaws within varied arguments.
Question 31Question →

Botanist: If a plant species originates in a tropical climate, it requires high humidity to thrive. The newly discovered Silvervine plant does not originate in a tropical climate. Therefore, the Silvervine plant does not require high humidity to thrive.

Which one of the following arguments exhibits a flawed pattern of reasoning most similar to that exhibited by the botanist's argument?

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Answer: If a vehicle is a commercial airplane, it has wings. This passenger train is not a commercial airplane. Therefore, this passenger train does not have wings.

Answer

The argument about the passenger train and wings perfectly mirrors the flawed structure of the botanist's argument.
The original argument exhibits a formal logic flaw known as illegal negation. It establishes a conditional statement (If Tropical -> High Humidity), states that the sufficient condition is not met (Not Tropical), and improperly concludes that the necessary condition is also not met (Therefore, Not High Humidity). The correct argument perfectly mirrors this flawed structure: it sets a rule (If Airplane -> Wings), negates the sufficient condition (Not Airplane), and falsely concludes the negation of the necessary condition (Therefore, Not Wings).

Step-by-Step Solution

1
Identify the logical structure and specific flaw in the botanist's argument.
Premise 1: Tropical -> High Humidity. Premise 2: Not Tropical. Conclusion: Not High Humidity. This is an Illegal Negation.
To find a parallel flaw, you must first precisely abstract the original argument's logical structure.
2
Evaluate the choices to eliminate arguments that use valid reasoning or different types of flaws.
The arguments about the greyhound and the indoor plant commit an Illegal Reversal. The basketball argument is a Part-to-Whole flaw. The smartphone argument is logically valid.
Options with different structural errors or no errors at all are incorrect in a Parallel Flaw question.
3
Match the exact abstract structure (Illegal Negation) to the remaining options.
The argument about the commercial airplane translates to: Airplane -> Wings. Not Airplane. Therefore, Not Wings.
The correct answer must replicate the exact logical pattern (If A -> B; Not A -> Not B) regardless of the subject matter.

Key Concept

Parallel Flaw: Illegal Negation
Question 32Question →

Pair each of the following flawed arguments with the argument that exhibits an identical pattern of faulty reasoning.

Click a left item, then click its matching right item

Items

If a city has a subway system, it experiences less traffic congestion. Springfield is currently experiencing less traffic congestion. Therefore, Springfield must have built a subway system.
Every individual puzzle piece in this box is shaped like a square. Consequently, when the puzzle is completely assembled, the final image will be shaped like a square.
Studies show that employees who take frequent walks report higher job satisfaction. Therefore, taking frequent walks directly increases an employee's job satisfaction.

Matches

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Answer

The city subway argument matches the baking powder argument (Illegal Reversal). The puzzle piece argument matches the brick building argument (Part-to-Whole). The employee walks argument matches the streetlight argument (Correlation vs. Causation).
Each pair correctly links a stimulus argument with a target argument that shares the exact same logical vulnerability: illegal reversal, part-to-whole composition, and confusing correlation with causation, respectively.

Step-by-Step Solution

1
Analyze the first argument about the city subway system.
Identify the flaw as an illegal reversal: 'If A (subway) then B (less traffic). B (less traffic) is true, so A (subway) must be true.'
Understanding the abstract structure of the error is required to find its match.
2
Find the matching flaw among the available options.
The baking powder argument uses the exact same structure: 'If A (baking powder) then B (cake rises). B (cake rises) is true, so A (baking powder) must be true.'
This establishes the first parallel flaw pair.
3
Analyze the second argument about the puzzle pieces.
Identify the flaw as a part-to-whole error (composition): assuming the whole has a property just because its constituent parts do.
Extracting the logical error allows for structural comparison.
4
Find the corresponding part-to-whole error.
The brick building argument assumes the whole building is light because individual bricks are light, directly matching the puzzle argument.
This establishes the second parallel flaw pair.
5
Analyze the third argument about employee walks.
Identify the flaw as confusing correlation with causation: assuming walks cause satisfaction simply because the two are linked.
Identifying the causal assumption isolates the final abstract flaw type.
6
Match the final argument.
The streetlight argument assumes streetlights cause lower crime just because they are correlated, which perfectly matches the employee walks argument.
This confirms and completes all parallel flaw pairings.

Key Concept

Parallel Flaw
Question 33Question →

If the city council approves the new zoning laws, the construction of the shopping mall will begin. If the construction of the shopping mall begins, the local traffic will increase significantly. Therefore, if the city council approves the new zoning laws, the local traffic will increase significantly.

Which one of the following arguments exhibits a pattern of reasoning most similar to that exhibited by the argument above?

Show answer & explanation

Answer: If the chef uses fresh herbs, the dish will be flavorful. If the dish is flavorful, the customers will be satisfied. Therefore, if the chef uses fresh herbs, the customers will be satisfied.

Answer

The argument about the chef using fresh herbs to satisfy customers.
The correct answer exactly mirrors the valid conditional chain presented in the stimulus. It sets up two conditional premises where the necessary condition of the first becomes the sufficient condition of the second (If A then B; If B then C), and validly concludes that the first sufficient condition guarantees the final necessary condition (If A then C).

Step-by-Step Solution

1
Analyze the logical structure of the stimulus.
The stimulus follows the valid transitive property: Premise 1 (If A -> B), Premise 2 (If B -> C), Conclusion (Therefore, if A -> C).
Identifying the formal structure of the original argument is required to find its exact structural match.
2
Evaluate the structure of the answer choices to find an identical match.
The correct answer has the exact same structure: Premise 1 (If Herbs -> Flavor), Premise 2 (If Flavor -> Satisfaction), Conclusion (Therefore, if Herbs -> Satisfaction).
A parallel reasoning question requires finding the option with the same exact logical validity and premise-conclusion relationship.

Key Concept

Parallel Conditional Logic
Question 34Question →

Consider the following two arguments:

Argument 1: If the orchestra performs a symphony, the concert will last over two hours. The orchestra is performing a symphony tonight. Thus, the concert will last over two hours.

Argument 2: If the temperature drops below freezing, the fountain will be turned off. The fountain is turned off tonight. Thus, the temperature dropped below freezing.

The pattern of reasoning in Argument 2 is logically parallel to the pattern of reasoning in Argument 1.

Show answer & explanation

Answer: False

Answer

False
The statement is False because the two arguments use different structural deductions. Argument 1 uses a valid logical structure (If A then B; A is true; therefore B is true). Argument 2 uses an invalid logical flaw known as affirming the consequent (If A then B; B is true; therefore A is true). Because their logical structures do not match, the reasoning is not parallel.

Step-by-Step Solution

1
Analyze the logical structure of Argument 1.
Argument 1 structure: If A (performs symphony) -> B (lasts over two hours). A is true. Therefore, B is true. This is a valid deduction.
Identifying the baseline structure is necessary to have a point of comparison.
2
Analyze the logical structure of Argument 2.
Argument 2 structure: If C (temperature drops) -> D (fountain turned off). D is true. Therefore, C is true. This is an invalid deduction (affirming the consequent).
Identifying the second structure allows for structural comparison with the first argument.
3
Compare the two logical structures to determine if they are parallel.
Argument 1 is a valid Modus Ponens structure, while Argument 2 is a flawed structure that affirms the consequent. They are not parallel.
Parallel reasoning requires the arguments to share the exact same logical framework, including validity.

Key Concept

Parallel Conditional Logic
Question 35Question →

Sociologist: Most of the residents in this neighborhood commute by train. Furthermore, most of the residents in this neighborhood regularly vote in local elections. Consequently, it must be the case that most of the residents in this neighborhood who commute by train regularly vote in local elections.

The flawed pattern of reasoning in the sociologist's argument is most closely paralleled by which one of the following?

Show answer & explanation

Answer: Most of the novels on the bestseller list are thrillers. Additionally, most of the novels on the bestseller list are written by debut authors. Hence, most of the thrillers on the bestseller list must be written by debut authors.

Answer

The correct answer is the option stating that most of the novels on the bestseller list are thrillers and most are written by debut authors, concluding that most of the thrillers on the list must be written by debut authors.
The correct answer exactly replicates the flawed logical structure of the stimulus: 'Most X are Y, and most X are Z. Therefore, most X that are Y must also be Z.' In the stimulus, X is residents, Y is commuting by train, and Z is voting. In this option, X is novels on the bestseller list, Y is thrillers, and Z is written by debut authors. Both arguments erroneously assume that the intersection of two majorities must itself constitute a majority of the first subgroup.

Step-by-Step Solution

1
Analyze the premises and conclusion of the original argument.
Premise 1: Most A are B. Premise 2: Most A are C. Conclusion: Most of the A that are B, are C.
To find a parallel flaw, we must first abstract the exact structural pattern of the argument.
2
Evaluate the validity of the abstracted structure to identify the flaw.
The argument is flawed because two 'most' statements about a single group do not guarantee that a majority of the first subgroup belongs to the second subgroup.
For example, if 51% of group A are B, and 51% of group A are C, they might only overlap by 2%. Thus, we cannot logically deduce that 'most' of B are C.
3
Examine the answer choices to find the one that matches this specific flawed structure.
The option about novels and thrillers perfectly matches the 'Most A are B, Most A are C, therefore Most of A that are B are C' structure.
Parallel flaw questions require matching both the logical mechanics and the specific type of error committed, ignoring surface-level subject matter traps.

Key Concept

Identifying and matching flawed quantifier logic (specifically involving overlapping 'most' statements).
Question 36Question →

Analyze the reasoning in each of the following short arguments. Pair each argument with the abstract description that most accurately identifies its primary logical vulnerability.

Click a left item, then click its matching right item

Items

If a municipality enacts restrictive zoning ordinances, local property values will invariably rise. Over the past decade, property values in the township of Oakhaven have risen dramatically. Thus, Oakhaven must have enacted restrictive zoning ordinances.
Every individual member of the Metropolitan String Quartet is an internationally renowned virtuoso. It logically follows that the Metropolitan String Quartet itself is an internationally renowned ensemble.
Recent sociological data reveals that regions with higher rates of daily internet consumption also report higher incidences of generalized anxiety. Therefore, it is evident that excessive internet consumption induces anxiety.
The two independent art critics we surveyed found the new abstract installation completely devoid of meaning. This definitively proves that no patron visiting the gallery will be able to derive meaning from the installation.

Matches

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Answer

The correct pairings match each specific flawed argument to its corresponding logical fallacy: the zoning argument contains an illegal reversal (sufficient/necessary flaw), the quartet argument commits a composition fallacy (part-to-whole), the internet argument confuses correlation with causation, and the art exhibit argument relies on an unrepresentative sample.
Each pairing accurately maps the specific logical vulnerability of the argument to its formal definition. The zoning argument confuses necessary and sufficient conditions. The quartet argument falsely equates the properties of individual parts to the whole. The internet argument jumps from correlation to causation. The art exhibit argument overgeneralizes from an exceptionally small sample.

Step-by-Step Solution

1
Analyze each stimulus argument on the left to isolate its premises and its conclusion.
The core reasoning structure of each argument is identified, stripping away the specific subject matter.
Parallel flaw analysis requires understanding the structural relationship between premises and conclusions, rather than the topical content.
2
Identify the specific logical gap or unwarranted assumption bridging the premises and conclusion in each argument.
The distinct fallacies are isolated: conditional reasoning reversal, part-to-whole projection, correlation-to-causation leap, and small sample generalization.
Pinpointing the exact nature of the flaw is necessary to find its abstract description.
3
Evaluate the abstract descriptions on the right and pair them with the arguments that exhibit the matching structural flaw.
Each argument is successfully mapped to its abstract logical error.
This completes the matching process by linking the applied reasoning to formal logical taxonomy.

Key Concept

Parallel Flaw - Identifying Abstract Logical Structures
Question 37Question →

All botanists possess a deep understanding of plant biology. Some participants at the current conference are botanists. Therefore, some participants at the current conference possess a deep understanding of plant biology.

Which of the following arguments is most similar in its logical structure to the argument above?

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Answer: All experienced pilots undergo rigorous training. Some members of the local aviation club are experienced pilots. Therefore, some members of the local aviation club undergo rigorous training.

Answer

The argument stating that all experienced pilots undergo rigorous training, some aviation club members are experienced pilots, and therefore some members undergo rigorous training.
The correct answer exactly mimics the structural logic of the original argument. The original argument states: All A (botanists) are B (deep understanding). Some C (participants) are A (botanists). Therefore, some C (participants) are B (deep understanding). The correct option states: All A (experienced pilots) are B (rigorous training). Some C (club members) are A (experienced pilots). Therefore, some C (club members) are B (rigorous training). Both are logically valid and use the exact same distribution of quantifiers.

Step-by-Step Solution

1
Analyze the logical structure of the stimulus argument.
Premise 1: All Botanists (A) -> Plant Biology (B). Premise 2: Some Participants (C) -> Botanists (A). Conclusion: Some Participants (C) -> Plant Biology (B).
To identify the exact quantifier logic pattern that needs to be paralleled.
2
Determine the validity of the stimulus.
The argument is a perfectly valid deductive syllogism.
Parallel reasoning requires matching both the structural terms (quantifiers) and the validity of the argument.
3
Evaluate the options to find the identical structure.
The correct argument matches the 'All A are B, Some C are A, thus Some C are B' structure perfectly using pilots, training, and club members.
This guarantees identical quantifier logic and deductive validity.

Key Concept

Parallel Quantifier Logic
Estimated Time:1m 0s
Question 38Question →

Match each flawed causal argument to the correct description of the logical fallacy it commits.

Click a left item, then click its matching right item

Items

Immediately after the new software update was installed, the computer network crashed. Therefore, the software update caused the crash.
People who use wheelchairs have a much higher rate of physical disability than those who do not. Clearly, using a wheelchair causes physical disabilities.
People who are seen carrying umbrellas are much more likely to be wearing rainboots. Thus, carrying an umbrella causes one to wear rainboots.
Eating excessive amounts of sugar is known to cause weight gain. Therefore, anyone who has gained weight must have eaten excessive amounts of sugar.

Matches

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Answer

The correct pairings match each specific argument with its corresponding causal flaw: temporal sequence to post hoc, wheelchair use to reversed causality, umbrellas/rainboots to a common third factor, and sugar/weight gain to assuming a sole cause.
Each argument perfectly demonstrates one specific causal fallacy. Matching them requires identifying the structural gap between the evidence provided and the causal conclusion drawn.

Step-by-Step Solution

1
Analyze the first argument regarding the software update.
Identify that the only evidence provided for causation is that the update happened immediately before the crash.
This matches the flaw of assuming causation based solely on a temporal sequence.
2
Analyze the second argument regarding wheelchair use.
Recognize that physical disability leads to wheelchair use, but the argument claims the opposite.
This represents the flaw of reversing the actual direction of cause and effect.
3
Analyze the third argument regarding umbrellas and rainboots.
Identify that rainy weather causes people to use both umbrellas and rainboots.
This matches the flaw of ignoring a common third factor that causes both phenomena.
4
Analyze the fourth argument regarding sugar and weight gain.
Note that while sugar causes weight gain, other factors can also cause weight gain.
This demonstrates the flaw of treating one possible cause as the only possible cause.

Key Concept

Identifying and categorizing distinct types of causal logical flaws.
Question 39Question →

To successfully cultivate the rare ghost orchid, one must precisely control the humidity of the greenhouse and use a specialized fungal fertilizer. The botanical garden has maintained precise humidity control in its new greenhouse and applied the specialized fungal fertilizer. Thus, the garden will certainly succeed in cultivating the ghost orchid.

Which of the following arguments exhibits a flawed pattern of reasoning most similar to that exhibited by the argument above?

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Answer: Sarah finished the qualifying race in two hours and fifty minutes and received a clean bill of health from her doctor. Consequently, Sarah will qualify for the marathon, because anyone who qualifies for the marathon must complete the qualifying race under three hours and pass a rigorous medical examination.

Answer

The argument concerning Sarah qualifying for the marathon replicates the identical flawed pattern of reasoning.
The correct answer replicates the illegal reversal of compound necessary conditions found in the stimulus. In the stimulus, the argument establishes that achieving a result (cultivating the orchid) requires two necessary conditions (humidity control and fertilizer), and then falsely concludes that meeting those conditions is sufficient to guarantee the result. The correct choice similarly states that qualifying for a marathon requires two conditions (time limit and medical exam), establishes that these conditions are met, and falsely concludes that this guarantees qualification. It perfectly mimics the logical structure while varying the order in which the premises and conclusion are presented to avoid superficial matching.

Step-by-Step Solution

1
Analyze the logical structure of the stimulus argument.
Premise 1: Successfully cultivating the orchid (A) requires humidity control (B) and fertilizer (C). [If A, then B and C]. Premise 2: The garden has humidity control (B) and fertilizer (C). Conclusion: The garden will succeed (A).
Identifying the formal abstract structure is required before evaluating the answer choices.
2
Identify the logical flaw in the stimulus.
The argument commits an illegal reversal (affirming the consequent). It treats two necessary conditions (humidity and fertilizer) as if they were jointly sufficient to guarantee success.
We must find an answer choice that commits this exact same abstract logical error.
3
Evaluate the answer choices to find a matching flawed structure, paying attention to reordered premises.
The correct argument states that qualifying for a marathon (A) requires a sub-three-hour race (B) and a medical exam (C). It notes Sarah achieved B and C, and concludes she will achieve A. This perfectly matches the [If A, then B and C; B and C, therefore A] structure.
The correct choice must replicate the compound necessary condition reversal, regardless of the order in which the sentences are presented.

Key Concept

Parallel Flaw - Confusing Necessary and Sufficient Conditions
Question 40Question →

Analyze the reasoning in each of the following flawed arguments. Match each argument with the abstract description that most accurately identifies its logical flaw.

Click a left item, then click its matching right item

Items

Every brick used in the construction of the new civic center is exceptionally small and fragile. It necessarily follows that the civic center as a whole will be exceptionally small and fragile.
Some of the firm's legal advisors are proficient in corporate tax law, and some of the people proficient in corporate tax law are also expert litigators. Thus, at least some of the firm's legal advisors must be expert litigators.
A recent public health study revealed that municipalities with a high concentration of fitness centers also have unusually high rates of locally-owned health food stores. This demonstrates that opening fitness centers in a municipality stimulates the creation of health food stores.
To receive a highly competitive research grant from the foundation, a scientist must have conducted experiments involving human subjects. Dr. Vance has conducted multiple experiments involving human subjects. Therefore, Dr. Vance will certainly be awarded the research grant.

Matches

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Answer

The civic center argument matches the part-to-whole flaw. The legal advisors argument matches the overlapping sets quantifier flaw. The fitness centers argument matches the correlation-causation flaw. The research grant argument matches the necessary/sufficient condition flaw.
Each argument represents a classic logical flaw commonly tested on the LSAT. By abstracting the specific subject matter and focusing entirely on the reasoning structure of each stimulus, we can accurately identify the corresponding abstract flaw description. This is a matching question, so all valid rationales are detailed in the correct pairs.

Step-by-Step Solution

1
Analyze the first argument regarding the civic center's bricks.
The argument moves from a characteristic of the components to a characteristic of the entire structure.
Identifying the premise-to-conclusion relationship reveals a classic part-to-whole (composition) flaw.
2
Analyze the second argument regarding the legal advisors and litigators.
The argument incorrectly assumes two distinct groups must overlap just because they both overlap with a common third group.
Diagramming the 'some' statements shows that the intersection of the two outer groups is logically unsupported.
3
Analyze the third argument regarding fitness centers and health food stores.
The argument takes a statistical correlation and concludes there is a direct causal relationship.
The premise only establishes that two things happen simultaneously, but the conclusion unjustifiably claims one causes the other without ruling out alternative explanations.
4
Analyze the fourth argument regarding the research grant.
The argument treats a strict requirement for an outcome as a guarantee of that outcome.
Translating the conditional language reveals an illegal reversal flaw, confusing necessary and sufficient conditions.

Key Concept

Parallel Flaw
Estimated Time:2m 0s
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