LSAT · Logical Reasoning58 flashcards

Cannot be true

58 flashcards covering Cannot be true for the LSAT Logical Reasoning section.

"Cannot be true" questions on the LSAT challenge you to analyze a scenario or argument and identify which answer choice must be false based on the given information. Unlike questions that ask what could be true, these require you to find the option that directly contradicts the details provided, often involving logical implications, assumptions, or relationships between elements. This helps build skills in precise reasoning and evaluating evidence, which are essential for legal analysis.

On the LSAT, these questions appear in the Logical Reasoning section, typically as part of stimulus-based problems where you must infer what's impossible from the facts. Common traps include overlooking subtle details or confusing what's possible with what's necessary, so focus on mapping out the logical structure and eliminating answers that could still hold. Mastering this topic improves your ability to spot inconsistencies quickly, which is crucial for scoring well.

Remember to read the question stem carefully to avoid misdirection.

Terms (58)

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    Cannot Be True Question

    A Cannot Be True question requires selecting the answer choice that must be false or impossible based on the information provided in the stimulus.

  2. 02

    Purpose of Cannot Be True

    This question type tests your ability to identify statements that contradict or are unsupported by the facts, evidence, or logic in the passage.

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    Key Difference from Must Be True

    Unlike Must Be True questions, which seek statements directly supported by the passage, Cannot Be True questions look for options that are inconsistent with it.

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    Approach to Answering

    To answer, evaluate each option against the passage and eliminate those that could be true, leaving the one that cannot be.

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    Common Stimulus Types

    Stimuli often involve scenarios with facts, arguments, or data, such as surveys, experiments, or logical chains, where inconsistencies can arise.

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    Role of Evidence

    In these questions, the passage's evidence must be used to determine what is impossible, focusing on direct contradictions rather than mere lack of support.

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    Spotting Contradictions

    Look for answer choices that directly oppose the passage's facts, such as reversing cause and effect or altering key details.

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    Conditional Logic in Cannot Be True

    If the passage includes conditional statements, check if an answer choice violates them by assuming a condition without its necessary consequent.

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    Percentages and Probabilities

    Answers involving percentages or probabilities cannot be true if they exceed or contradict the passage's data, like claiming a 100% certainty when only 80% is stated.

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    Assumptions in Cannot Be True

    While assumptions are key in other questions, here focus on whether an answer introduces information that the passage explicitly denies.

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    Common Trap Answers

    Trap answers often restate parts of the passage or introduce minor variations that could be true, distracting from the actual impossible option.

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    Negation Technique

    Sometimes, negating an answer choice can help verify if it's the one that cannot be true by checking against the passage's content.

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    Evaluating Quantifiers

    Be cautious with words like 'all,' 'none,' or 'some'; an answer that overgeneralizes beyond the passage's scope cannot be true.

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    Time and Sequence Errors

    If the passage describes a sequence of events, an answer that reverses or omits steps in a way that creates impossibility is the correct choice.

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    Causal Relationships

    Answers that misrepresent causality, such as claiming an effect causes its cause, cannot be true if the passage establishes the opposite.

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    Statistical Inconsistencies

    In passages with statistics, an answer that implies a result outside the data's range, like a negative percentage, cannot be true.

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    Hypothetical Scenarios

    For hypotheticals in the passage, an answer that contradicts the given conditions or outcomes is the one that cannot be true.

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    Analogy Pitfalls

    If analogies are used, an answer that extends the analogy in a way the passage doesn't support cannot be true.

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    Scope of the Passage

    Answers that go beyond the passage's discussed elements, making unsupported claims, may be impossible if they conflict with implied boundaries.

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    Inference vs. Contradiction

    Distinguish between drawing inferences and spotting contradictions; Cannot Be True focuses on the latter.

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    Multiple Choice Strategy

    Start by identifying what the passage clearly states, then test each option to see if it aligns or conflicts.

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    Advanced: Nuances in Wording

    Subtle word differences, like 'always' versus 'sometimes,' can make an answer impossible if the passage uses the opposite qualifier.

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    Dealing with Exceptions

    If the passage notes exceptions, an answer that ignores them and claims universality cannot be true.

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    Logical Flaws as Indicators

    Passages with flaws might make answers that exaggerate those flaws impossible.

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    Example: Basic Survey Data

    In a passage stating 60% of people prefer A, an answer saying 100% prefer A cannot be true because it exceeds the data.

    Survey: 60% like coffee. Answer: Everyone likes coffee.

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    Predicting Answer Choices

    Anticipate that correct answers often directly oppose a key fact, while incorrect ones are neutral or possible.

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    Common Error: Overlooking Details

    Students often miss small details in the passage that make an answer impossible, so read carefully.

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    Grouping Answer Choices

    Categorize options as 'possible,' 'must be true,' or 'cannot be true' to narrow down quickly.

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    Impact of New Information

    An answer introducing information not in the passage might be impossible if it conflicts with what's given.

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    Advanced: Counterexamples

    If the passage provides a counterexample, any answer denying its existence cannot be true.

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    Relationships Between Elements

    Examine how elements in the passage relate; an answer disrupting those relationships cannot be true.

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    Example: Cause and Effect

    If a passage says X causes Y, an answer claiming Y causes X cannot be true.

    Passage: Smoking causes cancer. Answer: Cancer causes smoking.

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    Avoiding Absolute Language

    Be wary of answers with absolute terms if the passage uses relative ones, as they often cannot be true.

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    Contextual Interpretation

    Interpret the passage in its full context; isolated facts might make an answer seem possible but not when combined.

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    Advanced: Implicit Contradictions

    Some contradictions are implicit, like assuming a universal rule when the passage shows exceptions.

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    Prioritizing Key Sentences

    Focus on sentences that state facts or conclusions, as they are prime for identifying what cannot be true.

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    Example: Population Data

    If a passage says a town has 1,000 residents, an answer saying it has 500 cannot be true.

    Town population: 1,000. Answer: Town has 500 people.

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    Misinterpretation Risks

    Answers that twist the passage's meaning, like changing 'increase' to 'decrease,' cannot be true.

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    Logical Deduction Limits

    While deductions can be made, an answer requiring an unsupported leap cannot be true.

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    Advanced: Probability Thresholds

    If a passage gives a probability range, answers outside that range, like 0% when 10-20% is stated, cannot be true.

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    Example: Conditional Statement

    In a passage, if A implies B, an answer saying A without B cannot be true.

    If it rains, the game is canceled. Answer: It rains but the game proceeds.

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    Balancing Speed and Accuracy

    Practice quickly eliminating possible answers to find the one that cannot be true without second-guessing.

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    Common Theme in Passages

    Many passages involve debates or studies, where opposing views make certain answers impossible.

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    Advanced: Layered Arguments

    In complex arguments, an answer that undermines a core layer without basis cannot be true.

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    Example: Historical Facts

    If a passage states an event occurred in 1900, an answer saying it was in 1800 cannot be true.

    Event date: 1900. Answer: Event in 1800.

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    Question Stem Variations

    Stems might say 'which of the following cannot be true' or 'which is not possible,' but the core task remains the same.

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    Avoiding Personal Bias

    Base judgments solely on the passage, not real-world knowledge, to correctly identify what cannot be true.

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    Advanced: Interconnected Claims

    If claims are linked, an answer breaking one link in a way that invalidates the whole cannot be true.

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    Example: Comparative Data

    If A is greater than B, an answer saying B is greater than A cannot be true.

    A > B. Answer: B > A.

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    Frequency of Question Type

    Cannot Be True questions appear regularly on the LSAT, often in sets with other inference types.

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    Strategic Elimination Order

    Eliminate answers that are clearly possible first, then scrutinize the rest for impossibilities.

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    Advanced: Subtle Inconsistencies

    Look for answers that create paradoxes, like a circle where A depends on B and B on A when the passage doesn't support it.

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    Example: Exclusive Categories

    If the passage says something is either X or Y but not both, an answer saying it is both cannot be true.

    Either X or Y. Answer: It is both X and Y.

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    Practice Tip: Timing

    Aim to spend no more than 1-2 minutes per question by efficiently cross-referencing options with the passage.

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    Overgeneralization Trap

    Answers that generalize beyond the passage's specifics, like from a sample to the entire population without evidence, cannot be true.

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    Advanced: Modal Verbs

    Words like 'must' or 'cannot' in answers can directly conflict with the passage's modal language.

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    Example: Quantity Limits

    If a passage limits something to 5 items, an answer claiming 6 items cannot be true.

    Limit: 5 items. Answer: 6 items present.

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    Integration with Other Skills

    This question type often requires skills from Must Be True and Strengthen/Weaken, but focuses on negation.