LSAT Explanation PT 30, S2, Q6: The student body at this university

LSAT Question Stem

Which one of the following arguments exhibits flawed reasoning most similar to that exhibited by the argument above? 

Logical Reasoning Question Type

This is a Parallel Flaw question. 

Correct Answer

The correct answer to this question is B. 

LSAT Question Complete Explanation

The question type for this problem is Parallel Flaw, which means we need to find an answer choice that exhibits flawed reasoning similar to the argument in the passage.

First, let's analyze the argument in the passage. The structure of the argument is as follows:

Premise: The student body at this university takes courses in a wide range of disciplines.

Premise: Miriam is a student at this university.

Conclusion: Miriam takes courses in a wide range of disciplines.

The argument commits an error of division, in which it assumes that because the whole (the student body) has a certain characteristic (taking courses in a wide range of disciplines), a part of the whole (Miriam) must also have that characteristic.

To better understand the error of division, let's consider a simple example: "The soccer team is very skilled. John is a member of the soccer team, so John must be very skilled." This reasoning is flawed because it's possible that not every member of the team is skilled, and John might not be one of the skilled players.

Now, let's consider an "Evaluate" question for this argument: "Does Miriam take courses in a wide range of disciplines?" The answer to this question will determine whether the argument is valid or not.

Now, let's analyze the answer choices:

a) The students at this school take mathematics. Miguel is a student at this school, so he takes mathematics.

This answer choice contains valid reasoning, not an error of division. If all students at the school take mathematics, and Miguel is a student at the school, then it's reasonable to conclude that Miguel takes mathematics.

b) The editorial board of this law journal has written on many legal issues. Louise is on the editorial board, so she has written on many legal issues.

This answer choice commits the same error of division as the argument in the passage. Just because the whole (the editorial board) has a certain characteristic (writing on many legal issues), it doesn't necessarily mean that a part of the whole (Louise) must also have that characteristic. Louise could have written on only a few legal issues or none at all.

c) The component parts of bulldozers are heavy. This machine is a bulldozer, so it is heavy.

This answer choice contains valid reasoning and moves from part to whole, which is the opposite of the error in the passage.

d) All older automobiles need frequent oil changes. This car is new, so its oil need not be changed as frequently.

This answer choice contains a Mistaken Negation, not an error of division.

e) The individual cells of the brain are incapable of thinking. Therefore, the brain as a whole is incapable of thinking.

This answer choice contains an error of composition, where the attributes of the parts are mistaken for the attributes of the whole. This part-to-whole error is the reverse of the error in the passage.

Based on our analysis, the correct answer choice is (B) since it exhibits flawed reasoning most similar to the argument in the passage, committing the same error of division.