Strengthening Arguments

TL;DR

Strengthening arguments questions ask you to find the answer choice that makes the conclusion more likely to be true. You'll identify the conclusion and premises, then look for an answer that fills a gap or adds support. The right answer doesn't prove the conclusion, just makes it incrementally stronger.

1. The Mental Model

Think of the argument as a wobbly table. Your job is to find the answer choice that adds an extra plank or leg to make it sturdier, not necessarily perfectly stable. You're looking to boost the probability of the conclusion.

2. The Core Material

Strengthening an argument means finding information that makes the reasoning presented slightly more convincing. It's not about proving the conclusion, but about increasing its likelihood. Most LSAT arguments have unstated assumptions or potential weaknesses; a "strengthen" answer often addresses one of these.

How to Approach "Strengthen" Questions

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1. Identify the Conclusion: This is the most crucial step. What is the author trying to convince you of? Look for conclusion indicator words (e.g., "therefore," "thus," "consequently," "it follows that," "should," "must") or simply ask, "What is this argument trying to prove?"

2. Identify the Premises: These are the facts or reasons the author provides to support their conclusion. Ask, "What evidence does the author give?"

3. Find the Gap (or Assumption): Most arguments aren't perfectly air-tight. There's usually a leap in logic or an unstated assumption connecting the premises to the conclusion. A strong strengthen answer often bridges this gap or makes that assumption more likely to be true.

   • Common Gaps:
     • Causation: If the argument concludes X causes Y, a strengthener might rule out an alternative cause for Y, or show X consistently precedes Y.
     • Analogy: If the argument uses an analogy, a strengthener might highlight similarities between the two things being compared.
     • Surveys/Samples: If the argument relies on a survey, a strengthener might confirm the sample is representative.
     • Generalization: If the argument moves from specific instances to a general rule, a strengthener might add more supporting instances or confirm the specific cases are typical.

4. Pre-phrase (if possible): After identifying the gap, try to think of what kind of information would close it. What would make the conclusion more likely given the premises?

5. Evaluate Answer Choices:

   • Focus on Relevance: Does the answer choice directly impact the connection between the premises and the conclusion?
   • Strengthen, Don't Prove: The correct answer doesn't need to make the conclusion 100% true. Even a small boost counts.
   • Avoid Irrelevant Information: Distractors often introduce new topics or simply restate parts of the argument without adding support.
   • Avoid Weakening Arguments: Be careful not to choose an answer that actually makes the conclusion less likely.

Here's a diagram showing the general flow for strengthening arguments:

graph TD
    A["Read the Stimulus"] --> B{"Identify Conclusion & Premises"};
    B --> C{"What's the relationship?\nAny gaps/assumptions?"};
    C --> D{"Pre-phrase: What would help?"};
    D --> E{"Read Answer Choices"};
    E --> F{"Does it make the conclusion more likely\ngiven the premises?"};
    F -- Yes --> G["Correct Answer"];
    F -- No --> E;

3. Worked Example

Stimulus: "Over the past decade, sales of organic produce have dramatically increased at local grocery stores. During the same period, there has been a noticeable decline in the number of customers reporting foodborne illnesses. Therefore, eating organic produce must lead to fewer foodborne illnesses."

1. Conclusion: Eating organic produce leads to fewer foodborne illnesses.
2. Premises:
* Organic produce sales increased.
* Reports of foodborne illnesses declined.
3. Gap/Assumption: The argument assumes a causal link between increased organic produce consumption and decreased foodborne illnesses. It doesn't consider other factors that might have caused the decline in illnesses.

Pre-phrase: An answer that rules out alternative causes for the decline in foodborne illnesses, or directly links organic produce to reduced illness risk, would strengthen the argument.

Answer Choices:
A) Many people who buy organic produce also buy other health-conscious products. (Irrelevant; doesn't link organic produce to illness.)
B) Local grocery stores have also improved their overall hygiene practices in recent years. (Weakens! Provides an alternative cause for decreased illness.)
C) Non-organic produce is often treated with pesticides that can sometimes cause digestive issues similar to mild foodborne illnesses. (Strengthens! This suggests a mechanism by which organic produce, lacking these pesticides, could reduce some types of "foodborne illnesses" or similar symptoms, thus supporting the conclusion's causal link.)
D) The number of local restaurants serving organic produce has also increased. (Irrelevant; doesn't directly connect eating organic to fewer illnesses.)
E) Public awareness of food safety has generally increased over the past decade. (Weakens! Another alternative cause for decreased illness.)

Why C is correct: Choice C provides a reason why organic produce might directly contribute to fewer illnesses (or symptoms mistaken for them) by highlighting a potential negative effect of non-organic produce that organic produce avoids. This directly supports the causal claim.

4. Key Takeaways

• Always identify the conclusion first; it's what you're trying to support.
• Premises are the evidence; understand how they're supposed to lead to the conclusion.
• Look for gaps in reasoning or unstated assumptions – strengtheners often bridge these.
• The correct answer makes the conclusion more likely, not necessarily certain.
• Eliminate answers that are irrelevant, weaken the argument, or only restate premises.

Common Mistakes to Avoid:
- Supporting a Premise: Don't pick an answer that just reinforces one of the given facts; it needs to strengthen the conclusion.
- Thinking You Need to Prove: You don't need to make the argument foolproof; even a slight boost is enough.
- Ignoring the Conclusion: Getting distracted by interesting but irrelevant information in answer choices.
- Choosing an Answer That Weakens: Carefully check if an answer choice actually has the opposite effect.

5. Now Try It

Take 15 minutes to find three "Strengthen" questions from your LSAT practice materials. For each question:
1. Clearly write down the conclusion and the premises.
2. Identify the main gap or assumption in the argument.
3. Before looking at the answer choices, try to pre-phrase what kind of information would strengthen the argument.
4. Then, evaluate the answer choices and explain why the correct answer strengthens the argument and why at least two incorrect answers do not.

Success looks like consistently and correctly identifying the conclusion, pinpointing the argument's vulnerability, and selecting the answer choice that directly addresses that vulnerability to make the conclusion more probable.