Logical reasoning PrepTest 138 · Section 3 · Question 23

Incorrect. A forger could go out of their way to purchase the materials that were used by the painter they are copying to make it easier to pass off as an original, so it's not necessary for the argument that those materials are readily available.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Necessary Premise

Stimulus Summary:
This painting's brush style is different from all known Cassatts, so it's not by her and is thus a forgery.

Answer Anticipation:
Let's start out by talking about how we cut out a lot of the elements in this argument. Since it's designed to prove that the work in question is a forgery, a lot of the information in this stimulus doesn't go to prove that! Anything that notes a reason to believe that Cassatt did paint this painting (the similar canvas, materials, and subject matter) is a concession the Historian is making to show that she's considered all the relevant details. The argument only gets started once she starts to note differences between Cassatt's paintings and this one, thus suggesting that it is a forgery.

With the argument summarized, we can see that it has an intermediate conclusion as well as a main point, so we can identify gaps in reasoning in either of those locations.

First, let's look at the gap between the main point and intermediate conclusion. If we accept that the painting isn't by Cassatt, does that guarantee it's a forgery? Not necessarily. It's been passed off as a Cassatt, but maybe calling it a forgery requires that the painter claim it as a Cassatt. So there's a gap here—anything that is claimed to be by a painter but isn't by that painter is a forgery.

Now, to the jump from the premise to the intermediate conclusion. There, the Historian claims that the painting is "definitely" not by Cassatt because it displays a different brush style than any of her known paintings. However, it's entirely possible that Cassatt experimented with a new brush style for this painting! The argument assumes that there aren't any "unknown" Cassatts out there with a different brush style.

Either assumption can be featured in a correct answer, so let's head into them looking for either.

Answer Explanation:
This answer highlights the gap between the premise and intermediate conclusion. If there are Cassatts out there that are painted with different brush styles than her known works, then the Historian's reasoning for believing this painting isn't by Cassatt doesn't hold water and the argument falls apart.

Key Takeaway:
When an argument has an intermediate conclusion, there's the potential for there to be an assumption/error in reasoning between the premises and that conclusion, and the intermediate conclusion/additional premises and the main point. Be sure to look for a gap in both jumps so that you don't miss a potential answer choice!

Incorrect. The information about Cassatt's subject matter isn't a part of the Historian's argument since it cuts against the conclusion. This answer might work to help establish that it's easy to spot a Cassatt, but a forger could easily intentionally copy that unique subject matter, or they could copy shared subject matter.

Incorrect. The brush style doesn't have to be the most characteristic feature of Cassatt's work to serve as a differentiator—it just has to be a characteristic feature of her work. If it's the second-most characteristic feature, the argument still holds together.

Incorrect. The argument only requires that the person who painted this painting didn't replicate the brush style of another Cassatt perfectly, not that no painter could replicate that brush style. This answer is too broad.