LSAT Explanation PT 22, S2, Q10: The only motives that influence all
LSAT Question Stem
The reasoning in the argument is fallacious because the argument
Logical Reasoning Question Type
This is a Flaw question.
Correct Answer
The correct answer to this question is B.
LSAT Question Complete Explanation
The passage presents an argument that states that the only motives that influence all human actions arise from self-interest. Based on this, the author concludes that self-interest is the chief influence on human action. The structure of the argument is as follows:
Premise: The only motives that influence all human actions arise from self-interest.
Conclusion: Self-interest is the chief influence on human action.
An "Evaluate" question for this argument would be: "Are there any other influences on human action that could be more significant than self-interest?"
The question type of this problem is Flaw, and we are asked to identify the fallacious reasoning in the argument.
Answer choice A is incorrect because the argument doesn't deny that an observation of a common trait can contribute to a causal explanation of the pattern.
Answer choice B is correct. The argument takes the occurrence of one particular influence on a pattern or class of events (self-interest) as showing that its influence outweighs any other influence on those events. Just because self-interest influences all human actions, it doesn't necessarily mean that it is the chief influence.
Answer choice C is incorrect because the argument doesn't involve any discussion of time, and there is no temporal flaw.
Answer choice D is incorrect because the argument doesn't conclude that self-interest is the only influence on human action. Instead, it says that self-interest is the chief influence.
Answer choice E is incorrect because the argument doesn't undermine its own premise. The premise is that the only motives that influence all human actions arise from self-interest.
In summary, the correct answer is B because the argument incorrectly assumes that just because self-interest influences all human actions, it must be the chief influence on human action.