Most LR questions are argument-based. Thus, it is very important to understand arguments and their 3 different parts, listed below:
- The Conclusion
- Premises or Evidence
Everything in the argument that isn’t some type of conclusion can be classified as evidence. Evidence is important to identify because on the LSAT it is always true. You will never get a correct answer by negating, arguing with, or contradicting the premises of the stimulus.
The conclusion, on the other hand, may be more or less plausible based on the evidence given. Its validity depends completely on how well it is supported by the evidence. You may be asked to identify the conclusion, strengthen it, weaken it, identify why the reasoning in the argument is flawed, or find an answer choice with parallel reasoning to the stimulus. More detailed information on LR question types can be found later in this chapter.
Kevin de Laplante of The Critical Thinker Academy explains how to distinguish between evidence and conclusion using keywords and context clues in the following video.
Assumptions are slightly more complicated. While the conclusion and the premises are stated in the argument, assumptions are not. Assumptions are implicit premises or ideas taken (or “assumed”) to be true but not directly stated. Therefore, the presence of an Assumption always indicates faulty reasoning or that the conclusion can’t be properly determined without more information. 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. The following video explains these two types of Assumptions and how to identify them.
Sean Murphy draws clear distinctions among the terms most, all, some, and none as they appear on the test and discusses how each term can and cannot be negated.
It is also important to note his discussion of the Denial Test as a clear and efficient tool to test the answer choices on all Necessary Assumption questions.