Logical reasoning PrepTest 122 · Section 2 · Question 23

Incorrect. The conclusion is about human behavior, and the stimulus discusses human behavior, so there's no analogy to be found.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Errors in Reasoning

Stimulus Summary:
Even if we knew every physical aspect of a human action, we wouldn't fully understand it, so it must be the case that behavior can't be understood just by understanding the physical aspects of that person.

Answer Anticipation:
There's a key word in this stimulus that it's easy to miss, but it highlights a type of word that you should pay attention to—"obviously." An adverb ("-ly" word) used to denote certainty is highlighting a conclusion, or the opinion of the speaker. Here, it's used to state that knowing all of the physical aspects of an action would "obviously" not let us fully understand it. Why not? Well, there's no reason given for why not, other than that human behavior cannot be fully understood without looking at the nonphysical aspects of a person.

So the support for the conclusion only makes sense if you also accept the conclusion as true? That's Circular Reasoning, friends! When the main point is support for a premise/intermediate conclusion, which is support for the main point, which is support . . . you get it.

Answer Explanation:
This answer describes a circular argument—one where the conclusion's truth is assumed, so it allows a certain premise/intermediate conclusion to be assumed, which then supports the main point which it already assumed was true. This answer is therefore correct.

Key Takeaway:
There aren't many examples of circular arguments on the LSAT, but this is one of them. Read it a few times to get a sense for how they sound so that you can spot one if it shows up on your test and, more importantly, so you know when an argument isn't circular since the most common incorrect answer in Errors in Reasoning questions is a circular reasoning answer.

Incorrect. This answer describes an absence of evidence flaw. However, the Commentator doesn't reach her conclusion by showing that an opposing point failed to prove the opposite conclusion, which would be required for this flaw to be present.

Incorrect. An argument doesn't need to raise every piece of evidence that would undermine its own conclusion—that would be a bad (and exhausting) way to argue. This answer doesn't describe a flaw.

Incorrect. The argument "suppose[s]" that there exists a complete scientific account for a human action—it raises it as a hypothetical. When you raise a hypothetical, you don't need that hypothetical to be practical or realistic—you can still think through the implications to prove a point.