Necessary Assumption Struggle

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• 2 Likes

  noonawoon Alum Member ⭐

  December 2019 3481 karma

  What has helped me for these is understanding that you are looking for the bare minimum to make the argument logically sound. When debating between two answer choices, pick the ones that just barely covers gaps in the argument, not the one that covers gaps and throws in extra info to strengthen the argument, because that goes above and beyond what is necessary. Feel free to PM me if you have a specific NA question you want to go over as an example! Always happy to help
• EveryCookCanGovern Alum Member

  December 2019 401 karma

  A NA is something that must always be true if the conclusion of the argument is to be true in relation with the supporting premises (in other words if the argument is to be valid). So take the premises given, add to that the answer choice of a NA, and ask yourself: does this need to be true for the for the conclusion to be true? There are three ways that an assumption must be true. One is that there is some gap between premises and conclusion that needs to be filled so that the latter is supported by the former. Another way is that the assumption defends the argument in some key way, an example is in causal arguments where the author assumes a single cause. If an answer choice in a NA rules out an alternate cause in a single cause argument, then this must be true, otherwise their argument falls apart. Another way that this defender role works is when an assumption protects the only premise given in support of a conclusion, because if that premise is destroyed then there is no longer any support structure and the argument falls apart.
• lsatgirl-1 Alum Member

  December 2019 256 karma

  @noonawoon @EveryCookCanGovern Thanks guys. I am going to write down these tips, and apply them while doing NA questions.
• 5 Likes

  Michael.Cinco Member Sage ⭐

  December 2019 2116 karma

  So as mentioned above necessary assumptions must be true for the conclusion to be true.

  There are two flavors of necessary assumption there are bridgers and defenders. Let's go into a bit of detail about each one.

  Bridgers act very similarly to sufficient assumptions. One of the things that should pop into your head when analyzing the stimulus is to look for elements in the conclusion that is not touched by the premises. This is a dead give away that you are dealing with a bridger. The right answer choice in this situation will often 'bridge' the gap between the premise and the disparate part of the conclusion you identified. This answer choice may sometime be both sufficient and necessary for the conclusion to be true but we will elaborate on what that entails further down.

  If you are not dealing with a bridger chances are you are dealing with a defender. A defender assumption defends the argument from potentially devastating attacks, if this defence was not available the argument would cease to be viable. This defence will be Taylor made to the argument in the stimulus and thus it is absolutely essential that you are very comfortable with the argument being made otherwise these defences will be hard to spot.

  Sufficient vs Necessary:

  On really difficult curvebreaker questions you will often be presented with answer choices that are sufficient but not necessary for the conclusion. These answers are tempting because they seem relevant to the argument being made and not only that they seem to really help your conclusion out. If you are dealing with a bridger this may be ok but for defenders these answer choices can be overzealous and go to far, a way to walk back from this type of answer is to ask yourself 'is this really necessary' often times these answer choices will use strong language with superlatives. Be leery of superlatives in the LSAT and especially so in necessary assumptions. The reason being that the nature of these answer choices take the impact of the answer choice from being necessary to being excessive. The next time you do a PT study the incorrect answer choices on NA questions and look for answer choices that fit this pattern. Think it through in relation to the stimulus and you'll begin to understand how these trap answer choices are constructed.

  TLDR

  1. Know the different forms of necessary assumptions

  2. Know the difference between sufficient and necessary

  3. You have to understand the stimulus 100% if you want a good chance of getting these questions right

  Bonus Tips:

  Do not forget to use the negation test. How you use it is totally dependant on your target score/ test taking strategy. If you are trying to score in the 90th percentile use it as a check rather than a brute force/poe eliminator as it could be a time sink.
• 2 Likes

  lsatgirl-1 Alum Member

  January 2020 256 karma

  @"Michael.Cinco" Thanks for the detailed explanation on the NA question. I have been using your tips, and they have been a great help .
• MambaMentality93 Alum Member

  January 2020 505 karma

  You may want to check out the NA webinar available and/or Powerscore and/or ThinkingLSAT probably got podcasts on NA questions