Skip to Main Content

PrepTest 73, Logical Reasoning 1, Question 18


Question 18, when a question asks about why an argument is flawed, obviously it's a flaw question, which means we have to identify the problem with the argument. But before we can do that, we need to understand the argument, which means understanding its conclusion and its evidence. The conclusion to this argument comes in the middle. However, this conclusion is wrong.

But in order to understand what conclusion they're saying is wrong, we have to read back a little bit to the conclusion that's wrong is that 15 century painters had a greater mastery of painting than did 16th century painters. Actually, they say this conclusion twice. Now the first sentence establishes that there is an argument that this argument is arguing with.

So there's a historian out there who thinks that because the 15th century European paintings were more planimetric than the 16th, the 15th were better. And then the final part is the evidence against that critic. Essentially the degree to which a painting is planimetric is irrelevant to the painters mastery. The flaw in this argument is fairly common on the outside of the absence of evidence flaw, the argument does prove that the art historians argument is bad.

But proving that someone's argument is bad is not the same thing as proving the opposite of their argument. For example, if you think that someone couldn't have committed a murder because they don't own a gun, and then you later find out that they do own a gun, finding out that they have that gun doesn't prove that they're the murderer. It just proves that your original argument wasn't very good.

And that's what's going on here. Just because being planimetric isn't enough to prove whether you're a bad painter is not itself enough to prove that these people are good painters. The critic has defeated the art historian's argument. But that's not enough to prove the art historian's conclusion. So we'll be looking for something that says that in the answer choices.

Now, answer choice A says that the argument rejects the position because the proponent of that position has other objectionable views. But art critic didn't do that, they didn't attack the art historian because of their objectionable views. So A is not the answer. Answer choice B illicitly relies on two different meanings the term mastery at no point in the argument do we have multiple definitions of mastery?

The critic is just talking about whether people are masters or not. Answer choice C, well, this is a very common flaw in the outset, it's just not happening here. This answer choice is describing a necessity versus sufficiency flaw, but nothing in this argument is established as being necessary or sufficient. So the argument isn't confusing the two.

You'll see this along the LSAT but you don't see it here. Answer choice D bases its conclusion on two claims that contradict each other. Now be careful, the word contradict means that two things can't both be true at the same time. It's not just saying that someone is arguing against someone else. So a contradiction will be like saying, you're on or my client couldn't have done the crime because he doesn't own a gun and because the gun that he owns was in the shop.

So there's no contradiction here, which means that the answer choice must be E. So let's see why. Rejects a position on the grounds that an inadequate argument has been for it. That was exactly the flaw that we predicted. The argument attacks the evidence that the art historian provides, which does disapprove the art historian's argument but that's not enough to reject the position that the art historian takes up.

So answer choice E is our answer.

Read full transcript