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Parallel Reasoning and Parallel Flaw

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Question 41Question →

Any proposal to overhaul the municipal zoning code will face opposition from the local historic preservation society if it includes provisions for high-density residential towers. The mayor's new housing initiative clearly includes provisions for high-density residential towers. However, it does not propose overhauling the municipal zoning code. Therefore, the local historic preservation society will not oppose the mayor's new housing initiative.

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

Show answer & explanation

Answer: Any tax reform legislation will be vetoed by the governor if it raises the corporate tax rate. The proposed budget bill clearly raises the corporate tax rate. However, it is not tax reform legislation. Therefore, the proposed budget bill will not be vetoed by the governor.

Answer

The correct answer is the option describing the tax reform legislation and the proposed budget bill.
The correct answer exactly parallels the stimulus's flawed reasoning. The stimulus establishes a compound sufficient condition (zoning overhaul AND high-density provisions) that triggers a necessary condition (opposition). It then introduces a scenario where one part of the sufficient condition is met (high-density) but the other is not (not a zoning overhaul), and fallaciously concludes the necessary condition will not occur (no opposition). This is a Mistaken Negation. The correct option mirrors this perfectly: it establishes a compound sufficient condition (tax reform legislation AND raises corporate tax rate) triggering a necessary condition (governor's veto). It introduces a scenario meeting only one condition (raises tax rate) but lacking the other (not tax reform), and incorrectly concludes the necessary condition won't occur (no veto).

Step-by-Step Solution

1
Analyze the logical structure of the stimulus argument.
The stimulus states that if a proposal is a zoning overhaul (A) AND includes high-density provisions (B), it will face opposition (C). It concludes that because a new initiative has (B) but is not (A), it will not face opposition (not C).
Understanding the exact structural formula and logical flaw is required to find a parallel argument.
2
Identify the specific logical flaw in the stimulus.
The argument commits a Mistaken Negation of a compound sufficient condition. It incorrectly assumes that failing to meet one part of a sufficient condition guarantees the necessary condition will not occur.
Parallel flaw questions require matching both the formal structure and the exact type of logical error.
3
Evaluate the options to find an argument with the identical flawed structure: (A and B) -> C; has B but not A; therefore not C.
The option regarding tax reform legislation matches perfectly: if it is tax reform (A) AND raises corporate tax (B), it will be vetoed (C). The budget bill has (B) but not (A), concluding it will not be vetoed (not C).
Only this option replicates the exact compound conditional structure and the specific mistaken negation flaw.

Key Concept

Parallel Reasoning and Parallel Flaw
Question 42Question →

Carefully read the following five arguments. Pair each argument with the abstract description that most accurately identifies its structural pattern of reasoning or its specific logical defect.

Click a left item, then click its matching right item

Items

If the new congestion pricing plan is enacted, downtown traffic will be reduced only if public transit capacity is expanded. The transit authority's budget was just severely cut, guaranteeing capacity cannot be expanded. Thus, if the congestion pricing plan is enacted, downtown traffic will not be reduced.
All consistently profitable retail chains in this sector have implemented highly automated inventory management systems. Omnimart recently completed the rollout of a comprehensive automated inventory system across all its regional stores. Therefore, Omnimart is guaranteed to become a consistently profitable retail chain.
Several species of amphibians in the coastal ecosystem have developed a physiological tolerance to the invasive fungus. Furthermore, several amphibian species in this ecosystem are currently experiencing a rapid population decline. Consequently, there must be at least one amphibian species in this ecosystem that has both developed a tolerance to the fungus and is experiencing a rapid population decline.
Any ethical framework grounded entirely in utilitarian principles will inevitably justify the infringement of personal liberties in extreme emergency situations. The newly drafted constitution's bill of rights absolutely prohibits the infringement of personal liberties under any circumstances. Therefore, the new constitution's bill of rights does not represent an ethical framework grounded entirely in utilitarian principles.
A municipal ordinance is considered legally enforceable if and only if it is approved by a majority vote of the city council and subsequently signed by the mayor. The recently drafted commercial zoning restriction was vetoed and never signed by the mayor. Thus, regardless of whether the city council overwhelmingly approved it, the zoning restriction is not legally enforceable.

Matches

Show answer & explanation

Answer

The arguments logically map to their abstract structures as follows: The congestion pricing argument validly establishes a conditional conclusion based on a failed requirement. The Omnimart argument commits a necessary-versus-sufficient flaw. The amphibian argument unjustifiably presumes subset intersection. The philosophical argument uses a valid contrapositive deduction. The zoning restriction argument validly denies a compound necessary requirement.
Each argument stimulus has a unique logical structure that precisely corresponds to only one abstract characterization. The congestion pricing argument perfectly matches the description of establishing a conditional conclusion via a failed necessary condition. The Omnimart argument precisely demonstrates the necessary-for-sufficient flaw. The amphibian argument showcases the subset intersection fallacy. The philosophical argument is a textbook contrapositive application. The zoning restriction argument validly denies a compound condition.

Step-by-Step Solution

1
Analyze the public policy argument regarding congestion pricing.
Structure: A -> (B -> C); ~C; Therefore, A -> ~B. This is a valid conditional deduction.
To identify its logical mechanism: proving a necessary condition for a conditional outcome cannot be met.
2
Analyze the corporate argument regarding Omnimart.
Structure: A -> B; B is true; Therefore, A is true. This is a classic formal logic flaw.
To identify the confusion between a necessary condition and a sufficient condition.
3
Analyze the biological argument regarding amphibians.
Structure: Some X are Y; Some X are Z; Therefore, Some X are Y and Z. This is flawed quantitative reasoning.
To identify the unwarranted assumption that two independent partial subsets must intersect.
4
Analyze the philosophical argument regarding utilitarianism.
Structure: A -> B; ~B; Therefore, ~A. This is a valid application of modus tollens.
To identify the correct application of a contrapositive inference to deny a characteristic.
5
Analyze the legal argument regarding the zoning restriction.
Structure: A <-> (B and C); ~C; Therefore, ~A. This is a valid deduction based on compound requirements.
To identify that the failure of one part of an 'AND' necessary condition guarantees the failure of the outcome.

Key Concept

Parallel Reasoning and Parallel Flaw analysis requires abstracting the logical skeleton of an argument and accurately mapping it to a descriptive formal characterization.
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