Logical reasoning PrepTest 122 · Section 4 · Question 16

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Necessary Premise

Stimulus Summary:
Most realistic art = Most truthful art
Intermediate conclusion - not Difference between beauty and truth → Most realistic art is best art
Pivot - Much of the most realistic art is not the best art
Conclusion - Difference between beauty and truth

Answer Anticipation:
This argument features a difficult philosophical argument with a complex structure, so let's break it down.

It opens with the conclusion—that there's a difference between beauty and truth. We know this is a conclusion because it's followed with "After all," which introduces support for whatever was just stated. Interestingly, this "After all" premise is also a conclusion, as it is followed by "since," showing that the second half of the sentence is support for it.

So we end up with a premise equating realism with truth supporting a conditional intermediate conclusion, and then a pivot which works with the intermediate conclusion to support the main point/opening line. Since there are two conclusions, we can look for gaps in logic in either place.

Let's start with the premise/intermediate conclusion—and let's take the contrapositive of that intermediate conclusion to get it to line up with the main conclusion:
not Most realistic art is best art → Difference between beauty and truth

The premise supporting this equates realism with truth—so we know that the most realistic art is also the most truthful art. If that's the case, then the most truthful art not being the best art would establish that there's a difference between truth and quality, but it wouldn't establish that there's a difference between truth and beauty, as the intermediate conclusion states. Thus, the argument is assuming a similar premise to that first premise connecting beauty and quality—the most beautiful art is the best art. That assumption is required to get to the intermediate conclusion.

Now, let's analyze the intermediate conclusion-to-main point portion of the argument. As we noted, the intermediate conclusion establishes that if the most realistic art isn't the best art, then there's a difference between beauty and truth (even though that was flawed, let's treat it as true to see if there's an assumption in this portion of the argument as written). That final premise (the pivot one) establishes that the most realistic art isn't necessarily the best art, which triggers the sufficient condition of that intermediate conclusion. That allows the necessary condition to be concluded, and the necessary condition is the main point of the argument, so there's no gap in this part of the argument.

Since the only assumption is between the premise and intermediate conclusion, that's what we'll need to look for in an answer!

Answer Explanation:
This answer establishes the "matching" premise to the one connecting realism and truth, which is necessary for the intermediate conclusion to hold. If the most beautiful art isn't the best art, then all of the other connections in the stimulus can't establish a difference between truth and beauty.

Key Takeaway:
Take these abstract/philosophical Strengthen with Necessary Premise questions slowly, and focus on the structure and connections drawn. You can usually find where the gap is by focusing on what is and isn't connected, finding the place where the lack of a connection creates a problem for the argument.

Incorrect. The argument establishes a positive correlation between more realism and more truthfulness, so it doesn't need to be the case that a single unrealistic element means there's a complete lack of truth.

Incorrect. This answer is a more extreme version of the pivot premise, which isn't required for the argument to work. In fact, the part of the argument relying on that premise was valid.

Incorrect. Very close! However, this answer is too strong. It needs to be the case that the most beautiful artwork is also the best artwork, not that all beautiful art is the best art.

Incorrect. The argument treats these factors as something that can be established as true, so subjectivity is out of scope (and, in fact, would hurt the argument).