Logical reasoning PrepTest 107 · Section 4 · Question 18

Question prompt

All actions are motivated Remaining source text redacted.
Why the credited answer is right

Credited answer: B

The notes below walk through why it fits the stem and how to eliminate the rest.

Argument or Facts

Argument

Valid or Flawed

Flawed

Question Type

Errors in Reasoning Questions

Stimulus Summary

Apparently altruistic actions can be seen as self-interested (example), so all actions are motivated by self-interest.

Answer Anticipation

This argument highlights a difference between how we use English colloquially and how the LSAT uses it, so we’ll circle back and discuss that in the takeaway. Here, we’re going to talk about three approaches to this argument.
The first is focusing on the concepts raised here. The conclusion is about motive - a concept frequently tested on the exam. Arguments that discuss motive are generally flawed because they assume that motive, action, and outcome are all aligned, when they don’t need to be. An action can have an outcome that runs counter to the motive behind it, and someone can take an action that’s unlikely to achieve their goal (people are irrational, after all). Here, the conclusion is about the motive behind all actions, but it’s based on how those actions can be described - in other words, a way of phrasing the outcome. That’s a shift, and so we can look for an answer that discusses it.
The second approach - which ends up getting us to the exact same place - is to focus on logical force, which is another key concept on the LSAT. Here, the conclusion is very strong - all actions are motivated by self-interest. We’d need an equally strong premise to back that up, but we don’t get it - we learn only that actions that seem altruistic can be described as self-interested. But that doesn’t mean that they are self-interested, just that it’s possible to describe them that way. This argument has a Weak Premise flaw.
The third approach focuses on an element that’s easy to gloss over - the premise is about how something is “described.” But the way someone chooses to describe something is a subjective one - things can be described inaccurately or, even if technically correct, they can be framed in a way that suggests something that isn't true. Here, the premise is about a description, which is subjective, whereas the conclusion is about what is true, which is objective. So this argument also has a Perception vs. Reality flaw.
All of these are describing the same jump in the argument, just in different terms, so let’s find an answer that lines up with any of them.

Answer choices

  1. A
    The term "self–interest" is Remaining source text redacted.
    Why choice A is not credited
    Self-interest is used to mean something that benefits the person (rewards or personal benefits), so there’s no Ambiguous Word Use flaw here.
  2. B
    The argument takes evidence Remaining source text redacted.
    Why choice B matches the stem
    This answer highlights the shift from a Weak Premise to a strong conclusion. The premise is about how actions can be viewed; the conclusion says that that possibility is certain.
  3. C
    The argument does not Remaining source text redacted.
    Why choice C is not credited
    Not all terms need to be fully defined - some words are used in their normal sense. Without a hint that these words were used to mean different things, this flaw isn’t present.
  4. D
    The argument ignores the Remaining source text redacted.
    Why choice D is not credited
    This answer describes a Sufficient (“suffices”)/Necessary flaw, but the argument doesn’t rely on conditional logic.
  5. E
    The argument depends for Remaining source text redacted.
    Why choice E is not credited
    The example cited doesn’t have only emotional content - it highlights a situation where an action could be seen as being motivated by self-interest.

What this tests

Question analytics

Based on historical answer selection rates for this question.

Answer choice distribution

  1. A 15%
  2. B Credited 59%
  3. C 4%
  4. D 21%
  5. E 1%

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