#17 - Must Be True, Purpose

[Administrator]

Complete Question Explanation
(See the complete passage discussion here: lsat/viewtopic.php?t=14161)

The correct answer choice is (B)

Purpose questions introducing a Specific Reference usually require a more complete understanding
of the context in which the referenced text appears, and are best approached with an active prephrase.

This question asks us to describe the purpose of the fourth paragraph, which is prephrased in the
VIEWSTAMP analysis above: to present an explanation of the Pin Factory model’s long-standing
failure to gain prominence among economists. Note the rhetorical question “Why?” in line 38, which
should help you focus on the relevant issue at hand. In addition, recall that Warsh’s argument is
inherently explanatory, not descriptive, suggesting that the correct answer choice is more likely to
contain keywords such as “explain” or “clarify,” rather than “outline” or “describe.”

Answer choice (A): The author neither describes, nor critiques, any theory purporting to resolve the
tensions between the Pin Factory and the Invisible Hand models.

Answer choice (B): This is the correct answer choice, as it most closely agrees with our prephrase.
Note that the degree of generality inherent in such descriptions can vary considerably, and should
not, by itself, serve as a reason to reject a particular answer choice.

Answer choice (C): This is an attractive answer choice, especially since the author does mention
some of the qualities that made the Invisible Hand model particularly attractive (it lends itself
more easily to “elegant formalism”). However, the purpose of the paragraph is not to outline these
qualities, but rather to explain why the Pin Factory model has been de-emphasized (line 38).
The “intuitions” in question are only outlined in so far as they help explain why one economic
assumption has dominated economic theory at the expense of another.

Answer choice (D): The fourth paragraph describes what caused economists to model one economic
assumption over another, not what tensions resulted from their attempts.

Answer choice (E): No particular argument is refuted in the fourth paragraph, or in the passage as a
whole.

[wulflov]

I narrowed this one down to (B) or (C), but incorrectly chose (C). I was torn because the first two sentences of the paragraph--"...the assumption of diminishing returns dominated economic theory, with the Pin Factory de-emphasized. Why?" suggest that what follows will be explaining why the Pin Factory was de-emphasized, e.g. what are "the intuitions supporting" the Invisible Hand emphasis. Some of what follows in the paragraph indeed explains some of the assumptions and mindsets--I don't know if these qualify as "intuitions"--that led economists to embrace the Invisible Hand theory. It's only the last sentence, almost an afterthought, that mentions how the Pin Factory model is "hard to represent mathematically," i.e. says what is a "difficulty associated with modeling" that assumption. And the difficulty is hardly "explained," rather than merely mentioned.

Any guidance as to why (C) is wrong, or less correct than (B)?

[Jonathan Evans]

Hi, Wulflov,

You're on the right track! Basically, there are no intuitions behind the assumption of diminishing returns of scale. Instead, these assumptions really are unwarranted and adopted only for expediency.

If I had to prephrase here before looking at the answer choices, I'd ask myself, "So what's the point of the fourth paragraph? How does it relate to the overall purpose/main point of the passage?"

Start by noting what the overall purpose of the passage is:

• The author attempts to explain developments with a long-standing difficulty with economic theory.

Now what does the fourth paragraph accomplish with respect to this idea? The first couple sentences provide excellent evidence. The author notes a long-standing problem and then asks why this problem has persisted. The paragraph answers this question! Therefore, to prephrase, we might say:

• The fourth paragraph attempts to explain why a certain problem in economic theory has persisted for so long.

This is a good match for Answer Choice (B), but note that it deviates markedly from (C). I hope this helps!

[moo]

Similarly to the earlier poster, I incorrectly chose option C. I'm having a little trouble understanding exactly why this answer was wrong because it seemed to me that there were intuitions behind the assumption of diminishing returns of scale—the intuitions involved being that the theory that was easier to document was more legitimate and that a theory that was rigorously modeled was more likely to be accurate than one that was not.

In contrast, answer B seems reductive/incomplete, because it only focuses on the difficulty with modeling the Pin Factory theory, not the fact that the difficulty with modeling the Pin Factory theory was the cause of its de-emphasization and the perpetuation of the competing Invisible Hand theory, which I took to be the true purpose of paragraph four.

[Frank Peter]

Hi Moo,

Try to keep in mind how this paragraph is serving the larger point of the passage as a whole. While we do get some content relating to the idea that there was this intuition that a theory should be able to be supported with numbers and equations, ultimately this serves the purpose of explaining the difficulty associated with modeling the Pin Factory. In other words, because it was the accepted practice that a theory should be able to be numerically represented, and because this was very difficult to do with the Pin Factory, this explains why it was de-emphasized for so long. We can imagine that if the practice of modeling a particular theory didn't require numerical representation in order to be acceptable, the Pin Factory would have gotten more traction earlier on.

[moo]

Thanks so much for your response!

The issue I'm having is that it doesn't seem clear to me that the fourth paragraph serves the passage by explaining the difficulty modeling the Pin Factory—instead, it seems to me to serve the purpose of showing why one idea dominated economic theory (the assumption of diminishing returns) while another (increasing returns to scale) was de-emphasized. The difficulty modeling the Pin Factory mentioned in answer B is only part of this larger concept; in contrast, answer C seems to do a better job of getting at the fact that the aforementioned difficulty caused one economic theory to become more popular and the other to become less popular.

As I look closer, I'm noticing that what probably made me think this is that both B and C use the word "assumption," but the word "assumption," to my mind, only fits the theory referenced in answer C (diminishing returns to scale), not the one in answer B (increasing returns to scale). It doesn't make sense to me to call the Pin Factory theory an assumption, because when the word assumption is used in the passage, it is clearly indicating how people assumed that the diminishing returns to scale theory was correct and assumed that the increasing returns to scale theory was incorrect. When "assumption" is used in C, it seems to illustrate how the diminishing returns theory was favored in the field of economics while the theory of increasing returns to scale was not. When it's used in B, it seems incorrect and out of place because the passage suggests that the diminishing returns to scale theory is the thing that gets assumed, not the increasing returns to scale or Pin Factory theory.

[Rachael Wilkenfeld]

Hi Moo,

Another way to look at the paragraph would be this: Is the purpose of the paragraph to support the diminishing returns theory or the Pin Factory model? We need to step inside the author's head a bit and try to determine WHY they wrote this paragraph. Is the author going to explain his support for the diminishing returns theory? No, because he supports the Pin Factory model.

Answer choice (C) says that the author's purpose is to give us the intuitions supporting the diminishing returns model. But that wouldn't move the author closer to their ultimate argument---that the pin factory model is a better model for many industries. The diminishing returns model is only discussed in comparison to the pin factory model. It's being compared/contrasted in order to explain why it is that the pin factory model was difficulty to support for those who value mathematical modeling and simplicity.

Purpose questions can be tricky, because they ask us to think about not only what is said, but why it was that the author said it. You have to combine the ideas in the specific paragraph mentioned with the overall argument of the passage to help figure out the purpose of the paragraph.

Hope that helps!
Rachael

[moo]

Thanks very much Rachael, I've thought about it for a while and this explanation makes more sense to me.