Necessary Assumption Questions

Comments

• June LSAT Retake Core Member

  February 2021 102 karma

  Following
• 1 Like

  kkole444 Alum Member ⭐

  February 2021 edited February 2021 1687 karma

  Hello,
  If I am in New York then I am in the United States.
  sufficient condition I am in New York
  Necessary condition (or has to be true), I am also in the united states.
  contra positive If I am not in the united states then I know I am not in New York.
  So when you are in new York it is necessary that you are in the united states, however if you are not in new york does that guarantee that you are not in the united states? NO, you could be elsewhere in the US. But if you are not in the US then we know you are not in new york.(contrapositive).

  Necessary conditions can be just about anything that is needed for the conclusion to be drawn.
  If you were to play a game of basket ball with your friends what would be necessary? a basketball, a hoop, and friends, and a plethora of other things(we assume them to be true, like you would have to be alive to play). If you leave out any of these things then you cannot play basket ball with friends. So a basketball, a hoop, and friends are all necessary in order to play basketball with your friends. So the LSAT could give you a stimulus about playing basket ball with friends and ask you what is necessary and could pick anyone of the three(basket ball, a hoop, friends) as the correct answer choice for the necessary assumption, however, the question are rarely that easy.
  the necessary condition is a condition that is needed in order for the argument to be able to conclude its conclusion properly(trying to get as close as possible to a valid argument as possible). With the necessary condition questions you are finding the necessary condition/assumption that when added to the stimulus makes the argument closer to a valid argument, it does not need to make it valid, it just needs to help the conclusion in the slightest way.
  If you post a problem that you are having trouble with many on this forum could help, if you are still struggling I would go back to the CC and review necessary assumption questions, I use to go back and re watch some of the core lessons so I really had a solid foundation on the principles.
• FautApprendreLSAT1 Core Member

  February 2021 314 karma

  Hey,
  One way to think of the necessary assumption is that it is proven/supported by the conclusion of the argument. Unlike the sufficient assumption, which proves the conclusion of an argument, the necessary assumption is instead proven by the conclusion. In the example Kole uses above being in NYC implies and supports that you are indeed in USA(the necessary condition). This, of course, is under the common knowledge that NYC is a city that is only found in the US. So, if you are in NYC, it is NECESSARY or must be true that you are also in the US. This is the reason why the negation test works to verify that you choose the correct answer. When we negate the necessary assumption, it destroys the argument. If the necessary assumption is not true, the argument cannot hold. If you are not in USA, you CANNOT be in the NYC(contrapositive). In practice, when I go through questions, I find the conclusion and premise of the argument first and then I ask myself "if this is true, what necessarily also has to be true?" Sometimes I can come up with guesses before even reading the answer choices, other times, just having that question in mind + the negation test, helps me figure out the right answer choice. Some of this is redundant here but hope this helps!
• 1 Like

  azizsardar Member

  February 2021 26 karma

  I had the same problem. I just finished going through the core curriculum on NA questions again. I feel like the key is to use the must be true method to narrow down your options and then use the negation test to confirm your answer. Once you've got the hang of it just do the NA problem sets in the CC until you have it down reasonably. If you find that NA questions are a time-sink, flag it and come back to it later. If that time is better spend getting other questions, move on.
• 1 Like

  JDream2025 Alum Member

  February 2021 996 karma

  The way I approach this is you find gaps. There will something said in the evidence, context and conclusion. An assumption is made. You just have to connect the dots. Once you find the answer, you then negate it because if you negate the right answer choice, it will destroy the conclusion, which essentially destroys your conclusion.