Necessary Assumptions

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• 6 Likes

  DrDisrespectFutureJD Alum Member

  March 2023 34 karma

  The key to necessary assumption questions is understanding that the answer choice, if it is not true, would destroy the argument. Go through every answer choice and ask yourself "does that have to be true for this argument to work?"

  If my argument was "Every person likes pie. So, Johnny must like pie." the necessary assumption I am making is "Johnny is a person." If Johnny is not a person, my argument simply does not work. After all, if Johnny is not a person, we cannot say he likes pie.

  This is a common tactic for necessary assumption questions. Negate the answer choice. Does the resulting negated statement completely wreck the argument? In this example, the negated assumption would be "Johnny is not a person." Well, that kind of destroys the argument. Look for the answer choice that, when negated, would destroy the argument or contradict it.

  Another thing you can do is to ALWAYS identify the conclusion and the premises supporting it. "Every person likes pie" is my premise and "Johnny must like pie" is my conclusion. Before you even read answer choices for necessary assumption questions, try to find the gap for yourself. This will come with more practice, but there will always be a gap in these arguments. What does the argument leap over to get to its conclusion? Sometimes, you'll anticipate the gap and immediately find the corresponding answer choice.

  Hope this helps. I recommend drilling necessary assumptions from the easiest question types to apply these tips. Then, work your way up. The higher the difficulty, the more subtle the assumptions will become.
• Juan23vr Live Member

  March 2023 304 karma

  loophole by cassidy is a good book
• 2 Likes

  valentina.soares-1 Alum Member Sage 7Sage Tutor

  April 2023 195 karma

  One thing has helped me is identifying my mindset or perspective when doing this type of question. When doing SA I think, "what is the missing link?" or, "how can I make these premises fit together to lead to the conclusion?”. When I approach NA questions I try to have a much wider mindset. I do not try to identify an answer before looking at the choices or presuppose an answer. Instead, I try to really identify the structure of the argument in the stimulus. You want to think about it as analytically as possible and really pull out those premises and the conclusion. Repeat to yourself, “ok they think X conclusion is true because of Y and Z reasons”. Usually then I’ll get suspicious about where problems might lie or where words they use in the conclusion seem like they’re too big of a reach from what was said in the stimulus. But again, I don’t try and pre-phrase. Then, when I get to looking at answer choices I am not searching for an answer, but seeing which of the 5 MUST be true.

  And this is another area where NA clicked for me. Thinking of these questions as Must Be True questions. Think of Necessary Assumptions as things we already know to be true based upon the stimulus. Because if it is necessary for the argument, then it Must Be True. We could take an NA question, remove its question stem, replace it with a Must Be True question stem, and nothing would change. You would still have the same right answer because the necessary assumption must be true if we assume the argument is valid.

  As others have mentioned, the negation test can be a great tool for deciding whether or not an answer choice is necessary, but I like to reserve this for when I’m truly stuck between two answer choices.

  In practice the process looks something like:

  Read stimulus and identify premises and conclusion

  Repeat to yourself "they believe conclusion is X for reasons Y and Z"

  See if anything makes you suspicious

  Read each AC and ask yourself does this NEED to be true for this evidence to validly lead to the conclusion?

  Not sure?

  Ask yourself, if it weren't true, what would happen? Would the argument be able to coexist with the negated answer choice? (Negate test)

  If not, then it is necessary, so it's our answer. It must be true.

  A Quick Note on Negating Answer Choices

  Make sure to translate the answer choice into its logical opposite, not its regular old English language opposite.

  The opposite of the statement "All people are standing" is "All people are not standing." In English, that means "No people are standing." It's the other extreme. We don't want this.

  The logical opposite of the statement "All people are standing" would be, "It is not the case that all people are standing." In English, that means "Not all people are standing" or "Some people are not standing."

  Its very important to know how to negate certain phrases like some, all, never, if/then statements, etc.
  Make sure you have these memorized so that you can quickly apply negations without confusion.

  Last thing I'll note is that correct NA answer choices are usually pretty vague or broad or easy to prove. Something that has super strong language is often going to be a red flag. Those are usually right for question types that require more powerful answer choices, both linguistically and conceptually. If you are not choosing an answer choice for NA just because it seems to obvious or simple, that's a bad reason to eliminate it!

  If you feel like you could still use some extra help with NA questions or any other LR question type or aspect of the LSAT, working with one of our expert tutors could be a great path to locking those down and picking up those missing points. A big part of our tutoring program is identifying your weaknesses, helping you understand how to improve them, and assigning you work in a weekly study schedule to practice and cement those concepts. We offer a free 30 minute consult with one of our tutors in which you can share your analytics and talk through how the program works and how our tutors would approach helping you reach your goal score through specifics. You can schedule this free consult using the following link if you are interested: https://calendly.com/7sage-consult/7sage-tutoring-free-consult?utm_source=FCA_A&month=2022-12

  Good luck!
  Valentina