Definition

The word "assumption" is used in everyday conversation in many ways, commonly used to mean "something a person probably believes ". Incorrect choices will commonly contain something that the author seemingly would agree with, but these are not necessary assumptions (and do we know whether or not the author would actually agree with the statement).

For the LSAT, you must be precise about the definition -- an assumption is an unstated premise that connects the stated premise and the conclusion. The LSAT will ask for assumptions that are "required", "necessary", or on which the argument "depends". For examples of incorrect choices that provide something the author probably believes (but we don't know for sure), see (A) and (C) on LSAT PrepTest 48, Section 4, Question 10. Also see (C) on LSAT PrepTest 50, Section 2, Question 22, as well as (B), (C), (D) on LSAT PrepTest 50, Section 4, Question 9.

 

Negating choices

Negating a choice to see whether it weakens the argument is an excellent technique for identify assumption questions. However, some choices will weaken the argument before the choice is negated. So, if you negate choices ensure that you do so precisely and carefully because if you try to cut corners and negate choices without careful precision, you may end up more confused than had you not used it. See LSAT PrepTest 50, Section 4, Question 11.

Negating choices provides the following benefits:

1- Turns difficult negative language into straightforward, easy-to-understand choices. See (D) on LSAT PrepTest 50, Section 4, Question 11.

2- Turns assumption questions into weaken questions. It's often easier to attack an argument rather than to simply analyze it. If you find that you're good at weaken questions and poor at assumption questions, try negating choices. See LSAT PrepTest 50, Section 4, Question 9.

3- Provides a different perspective. Even if you are equally good at weaken and assumption questions, by negating choices you will gain a different perspective and thus may understand the argument better by taking a different approach.

 

Distinguish between an assumption an implication/inference

Suppose you encountered the following information:

	If X g Y
	If Y g Z

This information implies that If X, then Z.

However, some might state : "From the above information, we may assume that If A, then C." However, this is an incorrect use of the word "assume". Instead, one should state: "From the above information, we may infer that If A, then C."

An assumption is an unstated premise. An implication (inference) is an unstated conclusion. Knowing the difference can help you out. See (A) on LSAT PrepTest 50, Section 2, Question 16, which might be tempting if you confuse "assume" and "infer".