Self-study
LR Stimulus Logic
29 LR Stimulus Logic tags
Ad hominem
Analogy (LR)
Bad authority
Causal chain
Causal reasoning
Circular reasoning
Conditional reasoning
Confusing sufficiency and necessity
Correlation
Diagram?
Eliminating options
Equivocation
False dichotomy
Internal contradiction
Kick it up
Lack of support v. false conclusion
Link assumption
Math
Mental state v. reality
Misdirected response
Part v. whole
Phenomenon-hypothesis (LR)
Quantifier
Relative v. absolute
Rule-application
Sampling
Time
Value judgment
Weighing factors
Ad hominem
Avg. 0.25 per section
Counterarguments that attack opponents directly instead of the substance of their reasoning, often accusing opponents of hypocrisy or bias. Learn more.
Correct answer criteria
- The stimulus features another viewpoint distinct from the author's, which the author criticizes
- The author's criticism does not respond directly to the opposing reasoning
- The author's reasoning relies on a premise about the other party directly
Key tactics
- Learn to recognize this common flaw by name when it appears
- When you catch it, go into "hunt mode" for the answer choices, scanning first for an answer that points to this flaw
Answer choice tips
- Example answer choices that point to this flaw:
- rejects an argument on the grounds that those making it have failed to abide by what the argument recommends
- dismisses the proposed ordinance because of its source rather than because of its content
- disputes a claim on the basis of a supposed motive for making the claim rather than by assessing the evidence relevant to the claim
- rejects a claim merely because the person making the claim stands to benefit by doing so
Analogy (LR)
Avg. 1.35 per section
Stimuli that feature arguments by analogy, where the success or failure of that analogy informs the answer choices. Learn more.
Logical Reasoning: Lesson 4 - City Council's Wisdom (W)
Logical Reasoning: Lesson 2 - Swimming Pools and Soft Drinks
Correct answer criteria
- To support a judgment in one situation, the author presents information about another, distinct situation that is purportedly similar in all relevant respects
Key tactics
- Arguments by analogy are common in every LR question type, in both sections of the LSAT, and also in the broader world of legal argument
- Learn to recognize them by name when they appear, and ask whether the analogy is well crafted or vulnerable to criticism
- The two things being compared in an analogy are always similar in some ways and different in others. What matters is if there are RELEVANT differences that affect the author's specific conclusion
Answer choice tips
- In "Flaw" or "Method of reasoning" questions, correct answers will often use the words "analogy" or "analogous" directly
- In other question types (WSE, NA, SA, etc.), information that bolsters or challenges the analogy is likely to appear in the correct answer choice
- For example, if the author argues for a certain tax policy in one country because it was successful in another country, look for information about relevant economic differences between the two countries
Causal chain
Avg. 0.4 per section
Stimuli that feature a chain of causal claims (e.g. A causes B, B causes C, so A causes C). Learn more.
Key tactics
- Causal chains often appear as support for causal conclusions. For example, if the conclusion is "A causes C," the premises could say "A causes B" and "B causes C." Evidence like this does lend some support for the conclusion by fleshing out the causal mechanism.
- That said, causal chains do not provide ironclad support. Most commonly, causal chains can be broken by introducing additional factors that outweigh those mentioned in the chain (see the "Weighing factors" tag).
- For example, let's say smoking cigarettes causes an elevated mood, and an elevated mood leads to improvements in physical health. While it's true that ONE element of cigarette smoking has a positive, indirect impact on physical health, OTHER elements of cigarette smoking directly damage physical health, undercutting the claim that "smoking cigarettes leads to improvements in physical health."
Answer choice tips
- If in a WSE question (most common), look for additional causal factors that could weigh against the chain's purported effects.
- Look also for link assumptions between the concepts in the causal chain, or between those concepts and the conclusion. Link assumptions are subtle shifts in terminology that mean the concepts being linked up change from one claim to the next.
- If in a MSS question, look for weakly-worded conclusions that merely assert that A can have some effect on C, as opposed to conclusions asserting a definite, overall causal relationship when other factors could be present.
Causal reasoning
Avg. 8.05 per section
Stimuli that feature the logic of causation (e.g. phenomenon-hypothesis, causal chain, experiments). Learn more.
Foundations: You Try - Minivans and Sports Cars
Foundations: Summary
Foundations: You Try - Decline in NGOs
Correct answer criteria
- The Causal reasoning tag applies to any stimulus that features causal premises or attempts to draw a causal conclusion.
- Flawed causal reasoning is one of the most tested concepts on the LSAT, but many stimuli feature causal reasoning that we're meant to treat as appropriate.
Key tactics
- When evaluating arguments featuring causal reasoning, keep the following questions in mind:
- Is the reasoning designed to explain a certain phenomenon? If so, are there potential alternative explanations for that phenomenon?
- What is the causal mechanism being proposed? Is that mechanism plausible?
- If the conclusion asserts that A causes B, could B plausibly cause A? Or could there be some additional concept C that causes both A and B?
Answer choice tips
- Example answer choices that point to flawed causal reasoning:
- fails to establish that the phenomena interpreted as cause and effect are not both direct effects of some other factor.
- does not consider the possibility of other causes of [the phenomenon].
- takes correlation to imply a causal connection.
Circular reasoning
Avg. 0.1 per section
Arguments for which accepting one of the premises involves having already accepted the conclusion. Learn more.
Conditional reasoning
Avg. 4.5 per section
Stimuli that feature conditional and set logic (e.g. A → B, A is true, therefore B is true). Learn more.
Foundations: Conditional Logic in 30 Minutes
Foundations: You Try - The Coffee Shoppe
Foundations: 4 Groups of Conditional Indicators Summary
Foundations: FAQ - Lawgic
Correct answer criteria
- The Conditional reasoning tag applies to any stimulus that features conditional claims (e.g. if ___, then ____), or claims about sets (e.g. all cats are mammals).
- Flawed conditional reasoning is one of the most tested concepts on the LSAT, but many stimuli feature valid conditional reasoning patterns as well.
Key tactics
- Fluency in formal logic diagramming (we call our language "Lawgic") is immensely helpful, both in the learning process and on the test itself.
- Diagramming takes time to learn, and it's normal for it to feel slow or confusing at first. For most students, it's worth the investment because it builds a deeper understanding of conditional logic that pays off on test day.
Answer choice tips
- THE important thing to note about conditional claims is that they cannot be reversed or negated. For example, consider the claim "All my friends are nerds":
- For example, the claim "All my friends are nerds" does NOT mean "All nerds are my friends" (that's reversed), and it does NOT mean "Anyone who is not my friend is not a nerd" (that's negated).
- In MBT and MSS questions you can expect wrong answers that express the claim you want, but reversed or inverted.
- In questions involving flawed arguments (Flaw, WSE, NA, SA, etc.), the conclusion will often be a reversed or inverted version of a supported claim.
Confusing sufficiency and necessity
Avg. 0.6 per section
Arguments that misinterpret conditional claims (A → B), either reversing them (B → A) or inverting them (/B → /A) to draw an invalid conclusion. Learn more.
Foundations: Confusing Sufficiency for Necessity
Logical Reasoning: Lesson 4 - A Secretive Trade Group
Correlation
Avg. 0.7 per section
Stimuli that involve two phenomena that are correlated with one another. Learn more.
Foundations: Correlation Phenomenon
Foundations: Correlations - Positive or Negative
Foundations: Correlation v. Explanation
Foundations: Competing Hypotheses to Explain Correlation
Correct answer criteria
- By contrast to "one-off" phenomena (e.g. Walt smoked for 30 years and got lung cancer), correlation phenomena describe change that happens together (e.g. how frequency of smoking relates to the odds of getting lung cancer).
- Correlative claims often appear as premises in causal arguments (which are then often flawed because correlation does not imply causation).
- But correlative claims also often appear as conclusions in their own right, with the premises offering data that purports to show that two things change together.
Key tactics
- Learn to recognize the crucial difference between correlative and causal claims -- correlation tells us two things change together, but does not tell us WHY they do so.
- When you see a correlative claim, it is very likely you're in a Phenomenon-hypothesis situation, and should therefore adopt the mindset and approach associated with that common pattern of reasoning.
Diagram?
Avg. 0.5 per section
Diagramming the logic is likely helpful (but not necessary) to solve the problem.
Eliminating options
Avg. 0.5 per section
Stimuli that reason by laying out a set of options, ruling some of those options out, then concluding we must choose the remaining option(s). Learn more.
Equivocation
Avg. 0.05 per section
Arguments that use a single term to mean two substantially different things, resulting in misleading or invalid reasoning. Learn more.
False dichotomy
Avg. 0.15 per section
Arguments that split the world up into two (or more) mutually exclusive, jointly exhaustive options, when in fact there may be additional available options, or the options given do not actually exclude one another. Learn more.
Internal contradiction
Avg. 0.1 per section
Arguments that feature two or more statements that are logically inconsistent with one another (e.g. "bread is delicious" and "bread is not delicious"), or set forth a rule and then come to a judgment that contradicts the rule.
Kick it up
Avg. 0.1 per section
Stimuli that are made significantly easier to understand by kicking some concepts up into the argument's domain. Learn more.
Lack of support v. false conclusion
Avg. 0.25 per section
Stimuli that reason from premises saying "A has not been proven" to a conclusion saying "A must be false." Learn more.
Link assumption
Avg. 3.2 per section
Arguments that feature an unjustified shift from one concept to another, which don't fit neatly into other common flaw categories (e.g. moving from premises about "houses" to a conclusion about "dwellings"). Learn more.
Math
Avg. 0.85 per section
Stimuli that require certain math skills for full comprehension. Most often "% v. amount" or "averages v. individual data points." Learn more.
Logical Reasoning: Math: Percentage v. Amount
Logical Reasoning: Math: Rates and Ratios
Logical Reasoning: Math: Averages
Mental state v. reality
Avg. 0.4 per section
Stimuli that feature a jump from a claim about reality to a claim about mental state (or vice versa) in a way that informs our evaluation of the answer choices. Learn more.
Misdirected response
Avg. 0.15 per section
Counterarguments that either mischaracterize their opponent's position, or fail to address key elements of their reasoning.
Part v. whole
Avg. 0.2 per section
Stimuli that assume characteristics that apply to something as a whole must also apply to all its parts, or vice versa. Learn more.
Phenomenon-hypothesis (LR)
Avg. 4.55 per section
Stimuli that describe a state of affairs (phenomenon), then offer a conclusion as to what has caused that state of affairs (hypothesis). A sub-type of causal reasoning. Learn more.
Quantifier
Avg. 1.2 per section
Stimuli that feature the logic of intersecting sets (e.g. some, most, all; might, probably, certainly). Learn more.
Relative v. absolute
Avg. 0.1 per section
Arguments that illicitly reason from relative premises (e.g. Fronk is taller than Spiro) to absolute conclusions (e.g. Fronk is tall), or vice versa. Learn more.
Rule-application
Avg. 1.7 per section
Stimuli that involve the application of a general rule to specific scenarios. Learn more.
Sampling
Avg. 0.95 per section
Stimuli that take data from a small pool (e.g. college students) and draw conclusions about a larger pool (e.g. people in general), where the sample pool may be unrepresentative of the broader pool (e.g. measuring science literacy). Learn more.
Time
Avg. 0.05 per section
Arguments that assume past circumstances (e.g. I have always lost the baking contest) guarantee circumstances in the present or future (e.g. I will lose tomorrow's baking contest).
Value judgment
Avg. 1.05 per section
Stimuli in which a jump from descriptive claims (i.e. "is" claims) to normative claims (i.e. "ought" claims) informs our evaluation of the answer choices. Learn more.
Weighing factors
Avg. 2.1 per section
Reasoning that involves considering or overlooking multiple factors pulling in different directions — whether causal forces with counteracting effects or costs and benefits of a decision — and determining how they balance out overall. Learn more.