LSAT 3 | Section 4 | Logical Reasoning: Q15

LR Question 15 Explanation

QUESTION TEXT: Exctinction is the way of nature. Scientists estimate that…

QUESTION TYPE: Flawed Reasoning

CONCLUSION: Humans are not to blame for recent species extinctions (the species would have become extinct anyway.)

REASONING: Most species were extinct before humans even existed. (therefore recent extinctions must have been caused by something other than humans)

ANALYSIS: This is a terrible argument. Life on Earth existed for a long time before humans did. Lots of extinctions happened, but they happened very slowly. Since we’ve been around, extinctions have happened quickly.

This is bringing in outside knowledge, of course. It’s fine to bring in outside knowledge to help you understand the context of a question. The only thing that isn’t fine is to make an assumption that contradicts the stimulus or that isn’t supported by the stimulus.

___________

1. The argument is only about extinction. The author might believe that technology has harmed other aspects of the environment.
2. This is relevant only if we have some strong reason to believe that the species about to become extinct will be killed by humans. The author would probably claim that any new extinctions are also caused by natural forces.
3. How does this affect the argument that humans did not kill species that have gone extinct?
4. The author was talking about a general scientific consensus. He did not cite specific scientists. If we’re making an argument, we don’t have to disagree with ourselves at every sentence.
5. CORRECT. This is a fancy way of saying that the author didn’t provide any evidence to show that we didn’t kill the species that have gone extinct since we existed. Obviously we didn’t kill the species that went extinct before we existed. But we might have killed modern species. The author doesn’t give any evidence that we didn’t.

Recap: The question begins with “Exctinction is the way of nature Scientists estimate that”. It is a Flawed Reasoning question. Learn how to master LSAT Flaw questions on the LSAT Logical Reasoning question types page.