On the LSAT, you must be able to identify any assumptions, or gaps, between the evidence and the conclusion. There are two types of Assumptions: Sufficient Assumptions and Necessary Assumptions. These questions typically ask you to identify the flaw and fix it. So, these are often like Strengthening/Weakening questions we just discussed.

CHALLENGE: Identify the Necessary Assumptions

Necessary Assumption questions have stems phrased in the following ways:

  • The argument requires/depends on/relies on the assumption that
  • Which of the following is an assumption on which the argument relies/depends?
  • Which one of the following is an assumption the argument requires?
  • The argument requires/depends on/relies on assuming which one of the following?

Notice that Necessary Assumption questions always contain a word that means “necessary” or “required”, while Sufficient Assumption questions ask for a guarantee that the conclusion will be reached.

Intro (0:01) | Ex.1 (4:23) | Ex.2 (13:09) | Trap Choices (18:07)
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Sufficient vs. Necessary Review

Sample Questions

Next LSAT: June 3rd

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Next LSAT: June 3rd