Introduction: Questioning the "Leap"
Welcome! In this part of your Thinking Skills journey, we are focusing on a vital skill for Paper 2: assessing challenges to inferences.
An inference is a "leap" our minds make. We take a piece of evidence (something we know is true) and use it to reach a conclusion (something we think is true because of that evidence). However, just because an inference is possible doesn't mean it is certain or even likely. Assessing a challenge means looking at that "leap" and asking: "Is there a reason this conclusion might be wrong?"
Don't worry if this feels a bit like being a lawyer in a courtroom—that’s exactly the mindset you need! Let’s break down how to spot and evaluate these challenges.
1. What is a "Challenge" to an Inference?
A challenge is a reason or a piece of counter-evidence that suggests an inference is weak, unsupported, or incorrect. When you are asked to assess a challenge, you are judging how much that challenge actually damages the inference.
Note: If you need to review how to make an inference first, check out the chapter on "Suggesting inferences from evidence."
2. Common Types of Challenges
To succeed in your exam, you should look for these four main ways to challenge an inference:
A. Alternative Explanations
This is the most common challenge. An inference usually claims that Evidence X happened because of Reason Y. You challenge this by suggesting Reason Z instead.
Example:
Evidence: The footprints outside the broken window match Mr. Jones’s shoes.
Inference: Mr. Jones broke into the house.
Challenge: Mr. Jones is the gardener and was working near that window earlier that morning. (This is an alternative explanation for why the footprints are there).
B. Over-Inference (Going Too Far)
Sometimes the evidence supports a small conclusion, but the inference tries to claim a huge one.
Example:
Evidence: A survey of 10 students shows they prefer pizza over salad.
Inference: No teenager in the country cares about healthy eating.
Challenge: The sample size is too small and unrepresentative to apply to all teenagers.
C. Correlation vs. Causation
Just because two things happen at the same time (correlation) does not mean one caused the other (causation).
Example:
Evidence: Ice cream sales and shark attacks both increase in July.
Inference: Eating ice cream causes sharks to attack.
Challenge: Both are caused by a third factor: warm weather, which leads to more people swimming and more people eating ice cream.
D. Challenging the Credibility of the Source
If the evidence itself comes from a source that isn't reliable, any inference drawn from it is automatically challenged. You can use the "RAVEN" criteria here (Reputation, Ability to see, Vested interest, Expertise, Neutrality).
Example:
Inference: The new car is the safest on the market because the car manufacturer’s spokesperson said so.
Challenge: The source has a vested interest (profit) to make the car sound better than it is.
3. How to Assess the Strength of a Challenge
In the exam, you won't just "identify" a challenge; you must assess it. This means deciding how much it weakens the original claim. Ask yourself these questions:
- How plausible is the challenge? Is the alternative explanation likely, or is it a "one-in-a-million" chance? A very likely alternative explanation is a strong challenge.
- Does it flat-out contradict the inference? Some challenges prove the inference is impossible, while others just make it less certain.
- Is there corroboration? Does other evidence support the challenge? If you have two different sources suggesting the same alternative explanation, the challenge is very strong.
4. Step-by-Step Guide for Exam Questions
When you encounter a question asking you to assess a challenge to an inference, follow these steps:
Step 1: Identify the Inference. Clearly state what conclusion is being drawn from the evidence.
Step 2: State the Challenge. Explain the alternative explanation or the weakness in the logic (e.g., "However, this evidence could also mean...").
Step 3: Evaluate the Impact. Use words like "significantly weakens," "slightly undermines," or "completely invalidates." Explain why it has that impact.
Quick Review: Key Terms to Remember
Inference: A conclusion drawn from evidence.
Alternative Explanation: A different reason why the evidence might exist.
Plausibility: How believable or likely a claim or challenge is.
Corroboration: When different pieces of evidence agree with each other.
5. Common Mistakes to Avoid
1. Confusing a "challenge" with just "saying no."
A challenge isn't just disagreeing. You must provide a reason why the inference might be flawed based on the evidence provided.
2. Ignoring the context.
Always look at the sources provided in Section A of Paper 2. If Source C provides a reason to doubt Source A, use that as your challenge!
3. Assuming "Possible" means "Certain."
Just because an alternative explanation is possible doesn't always mean the original inference is wrong. When assessing, be balanced. You might say: "While the inference is supported by Source A, the vested interest of the witness in Source B presents a significant challenge to its reliability."
Summary Key Takeaway
Assessing challenges to inferences is about finding the "weak spots" in the logic between evidence and conclusion. The strongest challenges usually involve providing a plausible alternative explanation or showing that the evidence does not represent the whole situation.