Logical reasoning PrepTest 151 · Section 4 · Question 21

Incorrect. The argument doesn't have a competing argument—no one is arguing that evolution always optimizes for survival.

Incorrect. The male moose are an example, not an analogy, since there's nothing they're being compared to (analogies are necessarily comparative).

Correct. Argument or Facts:
Argument

Valid or Flawed:
Valid

Question Type:
Methods of Reasoning

Stimulus Summary:
Male moose have an evolutionary feature that gives them an advantage (mating), but a disadvantage (getting eaten). Since the advantage could exist without the disadvantage, evolutions must not always optimize survival.

Answer Anticipation:
This argument raises an example meant to undermine a general proposition—namely, that evolution does optimize for survival. It doesn't note anyone who believes that, or why it's believed, but it does conclude that it isn't the case. So the correct answer should highlight that the argument uses a counterexample to disprove a general proposition.

Answer Explanation:
The male moose example challenges the general claim that evolution does always optimize for survival, thus serving as a counterexample that helps to establish an opposed generalization. Note the difference between how (A) and (C) are phrased—(A) talks about a competing argument, whereas this answer talks about a general claim. The conclusion here does imply an opposed general claim, but it doesn't imply any reasons to believe that claim—i.e., it doesn't imply an argument, just a generalization.

Key Takeaway:
There are two key pairs of phrases here that have subtle differences that are important on the LSAT.

(1) Argument vs. Generalization—An argument can reach a generalization as a conclusion, but without premises/support, a generalization isn't an argument.

(2) Example vs. Analogy—While an example used to counter another example could be described as an analogous situation, analogies require some type of comparison. In general, an example falls under a generalization, whereas an analogy compares two similar situations.

Incorrect. First, there's no indication that male moose are thought to support an opposing view (bringing up how it has an aspect supporting that view isn't the same as stating that someone thinks that is true). Second, the stimulus uses that example to undermine the general point, so the author believes it's relevant.

Incorrect. Showing that a certain evolutionary adaptation has both pros and cons doesn't mean that it's contradictory to believe the pros outweigh the cons.