Week 2: Necessary Assumptions (LR)

Question 1

Necessary Assumption Questions

Answer 1

Baseline requirement. Rest of the argument springs forth from the argument.

This statement must be true for the rest of the argument to be true.

Question 2

How to Spot Nec. Assumption: Language Cues

“Which one of the following is an assumption on which the arg. depends?”

“Reasoning above relies on which one of the following assumptions?”

“Which one of the following is an assumption required by the arg.?”

The conclusion follows logically only if which one of the following is assumed?”

“Presumes” is a different case.

• based on the wording ‘presume’ you know you’re dealing w/ an assumption.
• if you receive an assumption question and it doesn’t have any necessary or sufficient language, then you want to treat it as a _____________ assumption question.

Answer 2

default

Question 3

How to Solve Nec. Assumption

Answer 3

Just like you would any other question in the Assumption Family

• Nec. Assumption, Suff. Assumption, Flaw, Strengthen, Weaken

1. Conclusion
2. Evidence
3. Evaluate

• find the space between the arg.
• Find the gap, and why the arg. is invalid.
• grant that evidence is true, but ask “do I have to accept the conclusion?”

4. Anticipate (Prephrase)
5. Answer

Question 4

Types of Nec. Assumptions

When looking at your at your answer choices, you should typically think of assumptions in two frameworks: …

Answer 4

Linking

Defending

Question 5

Linking (Nec.) Assumptions

Answer 5

Think of linking assumptions as a journey, from one end to another.

Conclusion: A –> D

Evidence: A –> B, C –>D

Assumption: B –> C

pay attention to variables that need to be linked to complete the assumption.

Linking assumptions are pivotal to conditional logic!!!!

Alot of times, the test writers will put other variables in necessary assumptions to throw you off. Don’t fall for it. If some variables CANNOT connect the premises to the conclusion, then don’t waste time trying to make them fit in an answer choice. Link premise and conclusion ideas which have common variable(s).

Question 6

Defending Assumptions

Answer 6

When the argument doesn’t appear to have any missing link, switch gears and think ‘what is the argument maybe not considering right now?’

With the defending assumptions, the job is to defend the relationship between premises and conclusion from ideas, assertions, etc. that would weaken that relationship.

If you can figure out how to poke holes in the arg., you can defend it.

Question 7

Important Note: With defending assumptions, play the role of the ____________. Play the role of someone who despite the conclusion, says “yes, but…”. Be the person that tries to achieve what the conclusion is saying can’t happen.

Once you find the ideas that would weaken / poke holes in your conclusion, prephrase the opposite of those ideas.

• anticipate an AC that negates the idea / assertion that would weaken the conclusion.

Answer 7

debater.

Question 8

Trap Answer Patterns

Answer 8

Scope

• Out of Scope: AC’s that present info irrelevant to what’s being argued in stimulus.

Logic

• Weakens: answer choice does the opposite of what the conclusion is trying to prove.
• Irrelevant Relationship:
  • creating a relationship between two randomly chosen variables.
  • answer choice that uses reasoning structure separate from the one the stimulus uses.
• Mistaken Negation
  • A → B | ~A |… ~B
• Mistaken Reversal
  • A → B | B |… A
• Premise Support: supporting evidence when we’ve already accepted truth of the evidence, we’re trying to accept the truth of the answer choice.

Degree

• Too Strong: answer choice commits to an idea (even if its just one word) that’s stronger than what the stimulus says.

Question 9

Reasoning Structures

Answer 9

Different Depending on the type of Nec. Assumption

Linking Assumptions

• Conditional logic (pivotal for linking assumptions).

But, when there doesn’t appear to be any gaps in the argument, switch to Defending assumptions.

Defending Assumptions

• Think outside the box. What are somethings the argument didn’t consider that could weaken it?

Question 10

TWO IMPORTANT NOTES:

1. When you are down two contenders, use the Negation Test (aka, the Assumption Negation Technique). If you really wanna figure out which of your two answer choices support the argument (whether it’s a linking or defending assumption), negate your two answer choices. Whichever one directly attacks the argument (decreasing the likelihood of the conclusion) when negated, that is your answer choice, because if you were to take it out of negation, it would support the argument.
2. Resolve your QUALMS (doubts, reservations). Do not eliminate an answer choice all willy-nilly if you can’t actually reason as to WHY it’s a bad answer choice. Have a sound reason as to why you can eliminate your answer choices.