LSAT 143 | Section 1 | Logical Reasoning: Q13

LR Question 13 Explanation

QUESTION TEXT: Dr. Khan: Professor Burns recognizes that recent…

QUESTION TYPE: Most Strongly Supported

FACTS:

1. Professor Burns made observations of an area where a comet reservoir was claimed to appear.
2. Burns didn’t see the comet reservoir.
3. The observations happened in poor conditions.
4. Burns claims that her observations are enough to disprove the earlier sighting.

ANALYSIS: This question tests your understanding of how proof works. And it depends on common sense.

You know that poor conditions reduce the reliability of astronomical sightings. That’s common sense. You also know that poor conditions don’t necessarily make an observation worthless.

That’s about all we can say. Professor Burns’ observations don’t prove there’s no comet reservoir. But they at least tell us that it might not be visible in all conditions.

A lot of the wrong answers are based on incorrect logic about what we can prove and what we can’t.

___________

1. This doesn’t follow. Maybe the reservoir is very hard to spot. We might need more observations or better equipment to know for sure.
2. Nonsense. The poor conditions reduce the reliability of Professor Burns’ evidence, to be sure. But there’s no way that absence of a sighting can be interpreted as support for existence.
3. CORRECT. This is the best answer. Professor Burns claimed that her observations disproved the earlier sighting. But the poor conditions show that her observations are not as conclusive as she thinks.
4. Hard to say. If the comet reservoir was supposedly easy to see, then a single failure to observe it in good conditions might be enough to disprove its existence.
5. This is too strong. The recent observations either tell us “the comet reservoir may not be visible under all conditions”, and they slightly support the idea that it doesn’t exist.