LR Question 25 Explanation
QUESTION TEXT: If squirrels eat from a bird feeder, it will not…
QUESTION TYPE: Flawed Parallel Reasoning
CONCLUSION: If a feeder doesn’t have a cover, it won’t attract many birds.
REASONING: Squirrels keep birds from eating. Squirrels eat at a feeder only if it has no cover.
ANALYSIS: This argument makes a sufficient-necessary error. It’s possible for squirrels to eat from a feeder if it lacks a cover. But you don’t know if squirrels will eat from a feeder. Lack of a cover was just a necessary condition, not a sufficient condition.
- Conclusion: C ➞ B
- Evidence: S ➞ C AND B
These statements don’t match up. The conclusion incorrectly links two necessary conditions (C and B) that don’t have a relationship.
It’s important you see this structure before looking at the answers. They all use the same words, so structure is the only difference.
___________
- This is a bad argument, it ignores other reasons that tires can wear out. But it has a different structure from the stimulus. It uses ‘likely’, which doesn’t make a conditional statement.
- CORRECT. CP ➞ W is the conclusion
PL ➞ W AND CP is the evidence.
This argument has exactly the same structure as the stimulus. Two necessary conditions (W and CP) for low pressure are incorrectly linked. Don’t worry that ‘wear out’ is not negated – differences like that are not relevant to argument structure. - This argument introduces a moral principle, with the word ‘should’. The stimulus only talked about facts, not morals. This also doesn’t repeat the necessary condition error made in the stimulus.
- This is a good argument. Neglect ➞ Too low ➞ Wear out.
- This argument shows there are two possible causes of tire wear. Then it incorrectly says one cause is irrelevant because it’s not the only cause. This is not the error made in the stimulus.
More Resources for Flawed Parallel Reasoning Questions
- Conditional Reasoning Article: Learn about conditional statements.
- LR Diagrams Guide: Learn how to draw LR diagrams.
- Flaw drills: Practice identifying flaws.
- Intro Course lesson: This intro course lesson covers Flawed Parallel Reasoning questions.
- Mastery Seminar lesson: This LR Mastery seminar lesson covers flawed parallel reasoning questions.
Hi Graeme,
On the mastery seminars you emphasize narrowing down the answers on parallel questions without fully analyzing them. I searched for the necessary conditional like the only used in the stimulus on this one. That let me narrow it down to B (Only) and C (Unless). Do you find that valid? Is there any better way to go about it that you see?
Thanks in advance
I wouldn’t base it on words only. Here the structure is that they give the same sufficient condition twice:
* Squirrels eat –> few birds
* Squirrels eat –> lack cover
Then they incorrectly reverse the 2nd statement.
However, you narrowed correctly. Both B and C introduce two statements with the same sufficient condition. So perhaps you had been looking for that but described it differently. But LSAT questions always parallel on structure, not words.
Note: This is an old comment but I wanted to clarify the point.