Rank 13 by frequency | 31 questions in corpus (1.3% of all questions)
Discerning Principles questions ask you to identify an abstract principle or generalization that underlies, governs, or is consistent with an argument in the passage. The answer is a general rule or philosophical claim — not a specific scenario. Where Analogy asks "which scenario matches?" and Application asks "what follows in a new case?", Discerning Principles asks "what general rule drives this argument?"
This is the most abstract of RC's transfer question types. The passage gives you a concrete argument — artists should experience the world before depicting it, or legal texts should be interpreted by their words rather than legislative intent, or moral worth depends on social contribution. The question asks what general rule that argument commits the author to. Your answer is the philosophical claim that would have to be true for the passage's argument to work.
Four skills are at play. Abstraction: extracting a general principle from a specific argument. Philosophical reasoning: seeing the forest (the principle) rather than the trees (the specific claims). Principled consistency: evaluating whether an abstract statement is logically consistent with a specific argument. And, on comparative sets, cross-passage analysis: identifying which principles distinguish the two arguments.
The central move is Principle Extraction: moving from a concrete example in the passage to the abstract principle that licenses it. If the passage argues that "artists should experience the world before depicting it," the principle could be: "Excellence in a particular activity requires serious participation in that activity." If the passage argues that "legal texts should be interpreted based on their language, not legislative intent," the principle could be: "The meaning of a text is determined by its words, not the intentions of its authors." If the passage argues that "moral worth depends on social contribution," the principle could be: "What makes actions morally right is their contribution to the public good."
The hard part is the level of abstraction. The correct answer has to be abstract enough to count as a principle (not just a restatement of the passage's claim) but specific enough that it actually underwrites this argument rather than any argument. Correct answers use general language — "a practice," "an activity," "a system" — instead of passage-specific nouns. If you see your answer still talking about painters or statutes or particular moral cases, the abstraction level is wrong.
Three stem variations account for the 31 corpus questions.
Variation A — "Which principle underlies the argument..." (18 questions, 58%). The dominant phrasing. Asks for the principle that grounds or drives the argument. "Which one of the following principles most likely underlies the author's argument?"; "The conception of X that underlies the author's argument is best expressed by which one of the following principles?"; "Which one of the following principles is most in keeping with the passage's argument?" "Underlies" signals that the principle is foundational — the argument depends on it being true, even though it's never explicitly stated.
Variation B — "Which principle does the author use..." (5 questions, 16%). Asks which principle the author employs in their analysis. "Which one of the following principles does the author use in analyzing typical accounts of X?"; "Which one of the following principles is consistent with the author's approach?" Focus is on methodology — the principle is a tool the author uses, not just an assumption they rely on.
Variation C — Comparative-Passage Principles (8 questions, 26%). Asks about principles that distinguish or connect two passages. "Which one of the following principles underlies the argument in passage A but not the argument in passage B?"; "Which one of the following principles would both authors most likely endorse?" Disproportionately common on comparative passages (26% here vs. 11.4% base rate). Tests whether you can identify the abstract commitments that make two arguments different.
Step 1 — State the passage's concrete argument. Before trying to abstract, be crisp about what the author actually claims. A one-sentence version in your own words.
Step 2 — Ask what has to be true for the argument to work. The principle is the assumption the argument smuggles in. If the passage argues X from Y, ask: "Y only yields X if some general rule connects them." That rule is the principle.
Step 3 — Restate at the right abstraction level. Strip the passage's specific nouns (painters, statutes, particular moral cases) and replace them with general terms ("a practice," "a text," "an action"). Check that the resulting principle still supports this argument, not a different one.
Step 4 — Verify that the principle is logically necessary. Imagine the passage's argument without the principle: does the reasoning still go through? If the argument collapses without your candidate principle, you've found the right one.
The correct answer states the principle at the right level of abstraction. Not too specific: it doesn't just restate the passage's argument in different words. Not too abstract: it isn't so general that it could support any argument. Logically necessary: the passage's argument requires the principle to be valid. Free from passage specifics: it uses general language rather than the passage's particular subject matter.
Stems average 19.9 words, and the word "principle" or "principles" appears in virtually every one — the signature identifier of the type. Answer choices average 17.1 words and are abstract principle statements — generalizations of the form "The value of a practice depends on the extent to which it promotes the common good," "A system that permits X must also permit Y," or "Excellence in a particular activity requires serious participation in that activity."
Three real examples: Difficulty 4 — Comparative (LSAT April 2025, Q12): "Which one of the following principles underlies the argument in passage A but not the argument in passage B?"; correct answer (E): "Discriminating judgment concerning a particular activity is acquired through serious participation in that activity." Difficulty 5 — Single passage (LSAT January 2023, Q21): "Which one of the following principles does the author use in analyzing typical accounts of the origins of bebop?"; correct answer (D): "The turns of phrase employed by historians can legitimately be analyzed to uncover the historians' assumptions." Difficulty 4 — Moral principle (PT22, Q20): "The conception of morality that underlies the author's argument in the passage is best expressed by which one of the following principles?"; correct answer (A): "What makes actions morally right is their contribution to the public good."
Trap 1 — Plausible but wrong principle. The choice states a principle that sounds related to the passage's topic but doesn't actually underpin the argument. If the passage argues for experience-based expertise, this trap states a principle about innate talent. Defense: test whether the argument actually depends on the principle; if it doesn't, the principle is wrong even when topical.
Trap 2 — Too specific. The choice restates the passage's specific claim and calls it a "principle." It's not a principle — it's just the argument in slightly different words. Defense: reject any choice whose nouns are still the passage's nouns (particular moral cases, painters, statutes).
Trap 3 — Too abstract. The choice states a principle so general that it could support almost any argument, which means it doesn't specifically license this one. Defense: the correct principle is specific enough that dropping it would break the argument; overly vague principles fail this test.
This is one of the hardest question types in the RC corpus. Base difficulty is 4, and over 90% of examples are difficulty 4 or 5 — only one question in the entire corpus is difficulty 3. Questions stay at 4 when the passage's argument clearly depends on an identifiable principle and the correct answer states it at an appropriate abstraction level. They climb to 5 when the principle is subtle, when the argument is complex enough that multiple principles seem relevant, or when the question targets a comparative passage and asks which principle distinguishes the two arguments (26 of 31 examples are difficulty 4 or 5).
Single passages account for 23 of the 31 questions (74%); comparative passages account for 8 (26%). The type is disproportionately common on comparative sets, where it asks which principle one passage relies on but the other doesn't. Comparative passages provide a natural built-in contrast for testing principled distinctions, which is why the test maker leans on the format for this question type.
The word "principle" or "principles" in a stem is the signature identifier. Recognize it and switch into Principle Extraction mode: state the argument, ask what must be true for it to work, raise the abstraction level, and verify that the principle is logically necessary.