LSAT 152 – Section 2 – Question 18

LSAT 152 - Section 2 - Question 18

November 2018

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Question
QuickView		 Type Tags Answer
Choices		 Curve Question
Difficulty		 Psg/Game/S
Difficulty		 Explanation
PT152 S2 Q18
+LR
+Exp
Flaw or descriptive weakening +Flaw
Causal Reasoning +CausR
A
7%
156
B
11%
161
C
72%
163
D
6%
156
E
4%
158
134
148
163
 +Medium 147.463 +SubsectionMedium

Doctor: Angiotensinogen is a protein in human blood. Typically, the higher a person’s angiotensinogen levels are, the higher that person’s blood pressure is. Disease X usually causes an increase in angiotensinogen levels. Therefore, disease X must be a cause of high blood pressure.

Summarize Argument: Phenomenon-Hypothesis

The doctor hypothesizes that disease X causes high blood pressure, because it typically increases angiotensinogen levels, which are linked to higher blood pressure.

Identify and Describe Flaw

This is the cookie-cutter flaw of assuming that correlation proves causation. The doctor shows that disease X usually causes higher angiotensinogen levels and that higher angiotensinogen levels are correlated with higher blood pressure. She then jumps to the conclusion that disease X causes high blood pressure. To do this, she must assume that higher angiotensinogen levels actually cause high blood pressure. However, it’s possible that high blood pressure causes higher angiotensinogen levels, or that another factor like smoking or genetics causes both.

A
It confuses a necessary condition for a sufficient condition.

This is the cookie-cutter flaw of confusing necessary and sufficient conditions. The doctor doesn’t make this mistake; her argument relies on causal logic, not conditional logic.

B
It overlooks the possibility that even if a condition causally contributes to a given effect, other factors may fully counteract that effect in the presence of that condition.

The doctor’s argument is flawed because she assumes that angiotensinogen levels cause high blood pressure, not because she overlooks other factors that might counteract the effects of disease X.

C
It illicitly infers, solely on the basis of two phenomena being correlated, that one causally contributes to the other.

In order to conclude that disease X causes high blood pressure by raising angiotensinogen levels, the doctor must assume that high angiotensinogen levels cause high blood pressure. However, her argument only establishes that the two are correlated.

D
It confuses one phenomenon’s causing a second with the second phenomenon’s causing the first.

The only proven causal connection in the argument is that disease X usually causes higher angiotensinogen levels. The doctor doesn’t confuse this by saying that higher angiotensinogen levels cause disease X. Instead, she assumes that they cause high blood pressure.

E
It takes for granted that if one phenomenon often causes a second phenomenon and that second phenomenon often causes a third phenomenon, then the first phenomenon cannot ever be the immediate cause of the third.

This is descriptively inaccurate. The doctor says one phenomenon (disease X) causes a second phenomenon (higher angiotensinogen) and assumes that higher angiotensinogen causes high blood pressure. She then concludes that disease X is the immediate cause of high blood pressure.

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LSAT PrepTest 152 Explanations

Section 1 - Logical Reasoning

Section 2 - Logical Reasoning

Section 3 - Reading Comprehension

Section 4 - Logical Reasoning

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