Hello snuggs,
Good question! Let me see if I can help shed some light on the issue...
First, some basic concepts: in Justify questions, you need to identify a statement that is sufficient to prove the conclusion. In other words, if all the answers are true statements, one of them--when combined with the premises in the argument--will prove the conclusion. For example:
Premise: Snuggs just got a 172 on the LSAT.
Conclusion: Snuggs will be admitted to Harvard.
To justify this conclusion, it is sufficient to say that "Everyone who gets a 172 on the LSAT gains admission at Harvard" (i.e. 172
Harvard). Other examples of Justify answers include:
- 172 is a top-1% score, and a top-1% score is sufficient to secure admission to Harvard.
Everyone named "snuggs" is automatically admitted to Harvard.
Everyone who gets a score higher than 165 gets into Harvard.
Everyone taking the LSAT is automatically admitted to Harvard.
These examples all conform to the following structural paradigm:
- Justify Formula: Answer choice + Premise Conclusion
By contrast, Assumption questions require you to identify a statement upon which the conclusion
depends, i.e. a statement without which the conclusion wouldn't make any sense. In the above-mentioned Justify answers, none of them would be necessary for the conclusion to be true, because the conclusion would be logically valid even if they weren't true.
To identify an assumption, ask yourself, "What is the
least I need to establish in order to ensure that this argument is valid?" In a way, an assumption is an inferential statement - we can prove it by referring to the argument contained in the stimulus, so if the conclusion of the argument is true, the assumption(s) must be true as well.
Examples of assumptions for the above-mentioned argument might include:
- At least one person who gets a 172 is admitted to Harvard.
Snuggs is applying to Harvard.
Harvard will not reject Snuggs' application for some reason unrelated to her LSAT score.
The LSAT is one of the factors affecting applicants' chances of admission.
These examples all conform to the following structural paradigm:
- Conclusion Assumption
Assumption Negation Technique: Assumption NOT true Conclusion NOT true
In other words, all of these statements
must be true if my conclusion that "Snuggs will be admitted to Harvard" is true. Indeed, some test-takers find it easier to conceptualize Assumption questions as part of the First Family (i.e. "Prove"-type questions), because the assumption statement can be proven by the information contained in the stimulus.
Some of the problems you're experiencing with the distinction between Assumption/Justify questions might result from your attempt to relate the conditional relationship in the argument to the conditional relationship between the answer choices and the stimulus. The two have virtually nothing in common. The substantive logic of the argument may or may not contain conditional reasoning: the fact that it might is irrelevant to understanding the underlying conditional structure between the answer choices and the conclusion in Assumption/Justify questions.
Now, onto a more challenging argument containing conditional reasoning:
No one is admitted to Harvard without a top-1% score. Snuggs just took a Powerscore class, and everyone who takes a Powerscore class is guaranteed a 172. Therefore, Snuggs will be admitted to Harvard next year.
Conditionally, the argument can be diagrammed as follows:
- Premise: Harvard admission top-1% score
Premise: Snuggs Powerscore 172
Conclusion: Snuggs Harvard admission
Now, we know that Snuggs is guaranteed a score of 172, and Harvard requires a top-1% score for admission. Clearly, the conclusion assumes that 172 is a top-1% score. If it weren't, then Snuggs would not be getting into Harvard given the law school's requirement:
- Assumption: 172 top-1% score
This statement is not sufficient, of course, to prove the conclusion. Even if 172 were a top-1% score, that would only establish that Snuggs has satisfied a requirement necessary for admission into Harvard. Indeed, for us to prove the conclusion, we need to state that a score of 172 is sufficient to secure admission into Harvard (making the first premise into a bi-conditional statement):
- Justify: 172 Harvard admission
Let me know if this clears things up.
