LSAT 13 - Section 4 - Question 20

Here we have a flaw question, which we know from the question stem: “The argument is most vulnerable to the criticism at that…” Right away we know our correct answer has to do two things: be descriptively accurate, and describe the flaw of the stimulus. We also know what the wrong answers will do - describe reasoning flaws we’ve seen before, but don’t like up with our stimulus. Once we have a clear understanding of the questrion’s objective, we can proceed into structural analysis of the stimulus.

The argument begins by paying out two factual events; at the same time humans spread to America, several species went extinct. The stimulus goes on to conclude from this information we know that hunting on the part of the humans is what ultimately caused the extinction of these different species.

The word “cause” points out exactly what type of flaw we are dealing with. Our author assumes a causal relationship from a correlation between two variables. Remember that our conclusion, if valid, would be something that must be true on the basis of the premises. But it does not make sense to conclude one thing caused another if all we know is that those two events happened at the same time. Just because they occur at the same time does not preclude the possibility of a 3rd outside factor causing both human migration and the extinctions.

Knowing this stimulus incorrectly assumes causation from correlation, we can jump into the answer choices.

Answer Choice (A) This answer choice is not descriptively accurate. We are not introduced to a viewpoint where humans are seen as “not included in nature”. Rather, we are told that humans are so involved in nature there is an impact on the animals inhabiting this area.

Answer Choice (B) There are a few things that are not descriptively accurate about this answer choice. First, the answer accuses our argument of identifying a “myth” – a belief not based in objective fact and reason. But our issue with the argument is not the lack of reasoning. Our issue is that the reasoning provided does not lead us to our conclusion. Additionally, by telling us that the stimulus “presupposes what it attempts to prove,” answer choice B claims the existence of circular reasoning in our argument. When reasoning is circular, the conclusion is used as the evidence for the conclusion. We do not see an argument in the form of “B is true because B is true.” Knowing this, we can eliminate the answer choice.

Answer Choice (C) This answer choice does not contradict the content of our stimulus, but it is not the flaw of our overall stimulus. It is true that there may have been a different level of significance of the extinctions of animals in modern times versus prehistoric times, our stimulus is not concerned with the past versus the future. Instead, our answer choice has to describe something affecting something else simply because they exist at the same time.

Answer Choice (D) We can’t eliminate this answer choice based on its descriptive accuracy. There very well could have been many other species that went extinct after humans inhabited North America. But whether or not other animals happened to go extinct during this time period does not point out the problem with our stimulus. Our argument takes a specific position on what the extinction of some animals means. Whether or not there were additional extinctions does not point out the causal issue at play in this argument.

Correct Answer Choice (E) This is exactly what we are looking for! This descriptively accurate answer choice points out the issue in our author’s interpretation of the evidence. This is the only answer choice that attacks that interpretation while pointing out the far too strong causal relationship the author concludes.