Study guide
This chapter groups three question types united by a shared skill: recognizing structure independent of subject matter. Principle questions ask you to match a general rule to a specific case or vice versa, parallel reasoning questions ask you to match one argument's logical form to another about a completely different topic, and method-of-argument questions ask you to describe how an author argues rather than what the argument concludes. Success in all three depends on being able to strip an argument down to its skeleton.
Principle Questions: Two Directions
Principle questions come in two directions, and telling them apart early saves time. In one direction, the stimulus gives you a specific situation, and you must identify the general principle, among the answer choices, that would justify or explain the judgment made about that situation; the correct answer is the broadest rule that, if true, would make the specific judgment reasonable. In the other direction, the stimulus gives you a general principle, and you must identify which specific scenario, among the answer choices, the principle would apply to or justify; here the correct answer is the specific case that actually satisfies every condition the principle sets out. A frequent trap in the second direction is an answer choice that satisfies most, but not all, of the principle's stated conditions, relying on the reader to overlook one clause. For example, if a stated principle holds that a promise should be kept unless keeping it would cause serious harm to an innocent third party, a correct matching scenario must show both that a promise was made and that no such serious harm to an innocent third party exists; a scenario involving only minor inconvenience to the promisor does not satisfy the exception and should not be selected as an example of a case where the promise may be broken. Read principle statements the way you would read a rule with conditions attached, checking each condition against the candidate scenario individually rather than judging the scenario's overall feel.
Parallel Reasoning: Matching Logical Form
Parallel reasoning questions ask which of the following arguments is most similar in its pattern of reasoning to the argument above, and the answer choices are always about a different, often unrelated topic, precisely to prevent you from matching on subject matter instead of logic. The task is to identify the stimulus argument's abstract structure, meaning the number and type of premises, the type of conclusion, and, importantly, whether the argument is logically valid or contains a specific flaw, then find the answer choice sharing that exact structure. If the original argument commits unsupported causation from a correlation between two variables, the correct parallel answer must also commit unsupported causation from a correlation, even though its topic might be totally unrelated, such as classroom attendance and grades instead of fire trucks and fire damage. A reliable method is to label each sentence in the stimulus with a generic tag, such as most A are B, this C is an A, therefore this C is probably B, and then check each answer choice sentence by sentence against that same labeled pattern, discarding any choice as soon as one sentence fails to match either in logical role or in strength (contrast all versus most, or probably versus certainly). Because parallel reasoning questions are usually longer, with five multi-sentence answer choices, working systematically sentence by sentence is faster and more accurate than reading each answer choice as a whole and judging by overall impression.
Parallel Flaw: A Special Case
A closely related variant, sometimes phrased which of the following contains a flaw most similar to the flaw in the argument above, is often called parallel flaw. This variant combines the skills from the flaw chapter with the structural matching of ordinary parallel reasoning: first diagnose the exact flaw in the stimulus using the vocabulary from unsupported causation, illicit conversion, or overreach, and then find the answer choice that commits that same named flaw, regardless of topic. The temptation on parallel flaw questions is to select an answer choice merely because it is also a bad argument; but the LSAT tests whether the specific type of badness matches, not whether both arguments happen to be weak. An argument that commits illicit conversion is not a match for an argument that commits unsupported causation, even though both are flawed. Because parallel flaw stimuli are always defective, do not waste time trying to strengthen or repair the original argument; your only task is to name its flaw precisely, then search for the same flaw elsewhere. This precision is exactly what separates a correct parallel flaw answer from an attractive but structurally different distractor.
Method of Argument Questions
Method-of-argument questions, phrased as which of the following describes the technique of argument used above or how does the author respond to the objection, ask you to describe the argumentative strategy at a structural level, not to evaluate whether the argument succeeds. Common techniques include arguing by counterexample, where the author refutes a general claim by presenting a single case that violates it; drawing an analogy, where the author argues that because two situations are alike in relevant respects, a conclusion true of one should hold for the other; appealing to a general principle and then applying it to a specific case; and undermining an opponent's argument by showing that its premises, if true, would also lead to an implausible or unwanted conclusion, a technique sometimes called reductio ad absurdum. When a stimulus includes two speakers, such as a dialogue between an initial claim and a reply, method-of-argument questions often ask specifically how the second speaker responds, and the correct answer usually describes whether the second speaker directly rebuts a premise, questions an assumption, offers a counterexample, or reframes the issue rather than truly engaging with it. As with flaw and parallel reasoning questions, correct answers here are written at an abstract, structural level; an answer choice that describes the topic rather than the technique is not addressing what the question asks.
Key terms
- Principle question
- — A question type asking you to match a general rule to a specific case, or a specific case to the general rule that justifies it.
- Parallel reasoning question
- — A question type asking which answer choice shares the same abstract logical structure as the stimulus argument, regardless of topic.
- Parallel flaw question
- — A parallel reasoning variant in which the stimulus argument is flawed and the correct answer must share that same specific flaw.
- Logical form
- — The abstract structure of an argument, including the type and number of premises and the type of conclusion, independent of its subject matter.
- Method-of-argument question
- — A question type asking how an argument is constructed or how one speaker responds to another, described at a structural level.
- Argument by counterexample
- — A technique that refutes a general claim by presenting one case in which the claim does not hold.
- Argument by analogy
- — A technique that concludes a claim true of one situation should also hold for a second, relevantly similar situation.
- Reductio ad absurdum
- — A technique undermining an argument by showing its premises lead to an implausible or clearly unwanted conclusion.
- Structural matching
- — The practice of comparing arguments sentence by sentence for logical role and strength, rather than for shared subject matter.
Exam tips
- Before reading principle answer choices, identify every condition the principle imposes and check each one individually against the specific case; a scenario missing even one condition is not a match.
- On parallel reasoning questions, label each stimulus sentence by its generic logical role first, then test answer choices sentence by sentence rather than by overall impression.
- On parallel flaw questions, name the specific flaw before scanning the answer choices; being merely bad in some way is not the same as being bad in the same way.
- Watch quantity and certainty words closely when matching structure, since a shift from most to all, or from probably to certainly, breaks an otherwise strong parallel match.
- On method-of-argument questions, describe the technique in structural terms (counterexample, analogy, principle-application) rather than summarizing the topic.