LSAT Logical Reasoning: Assumptions, Strengthen, Weaken, and Inference
Logical reasoning begins with a simple discipline: identify the task before evaluating an answer. An assumption question, a strengthen question, a weaken question, and an inference question can use similar language while asking you to do different things. Read the question stem closely, then separate the premises from the conclusion.
Find the gap between evidence and claim
An argument may move from one group to another, from a correlation to a cause, or from a limited observation to a broad prediction. Describe that move in a short sentence. For example: 'The argument assumes what worked in one location will work in another.' This gives you a specific relationship to examine.
For a necessary assumption, look for something the argument needs. Negating the answer should expose a serious failure in its support. A sufficient assumption has a different job: when added to the premises, it must make the conclusion follow. Something helpful can fall short of either standard.
Match the answer to the task
Strengthen answers improve the support for the conclusion; they do not have to prove it. Weaken answers reduce that support; they do not have to establish that the conclusion is false. Ask what the new information changes about the connection between the evidence and the claim.
For an inference task, reason from the information given. If the stem asks what must be true, the answer needs to follow, not merely sound plausible. If it asks what is most strongly supported, respect that wording. In either case, avoid importing outside facts or turning 'some' into 'most.'
Train it. Feel it click.
Try two cards from the app’s current training bank. Pick your vibe, swipe up or down or tap an answer, then learn why it works. These original LSAT BEAST drills are not official LSAT® questions.
A shopper assumes Vivet’s streaming backpack and travel backpack are interchangeable. New fact: The streaming design covers broadcast equipment, while the travel design carries personal items.
Two cards from the current training bank. Preview points stay in this sprint.
A common mistake to catch.
Do not select an answer merely because it discusses the same topic. A new fact must affect the claim’s support to strengthen or weaken it. For an inference, ask what the words require, not what sounds likely.
Your next rep.
For each practice question, write three brief notes: task, conclusion, and reasoning gap or inference rule. Review why your chosen answer meets that specific task. Build vocabulary with LSAT BEAST drills, then apply the same process to official LSAT® questions through LawHub®.
Official resources
The explanations and training cards above are original LSAT BEAST material. Use LSAC’s resources for official questions and current test information.