Q1 - A major art theft

[geverett]

I had a hard time choosing between B and C. I ultimately got it right by choosing C, but would love to start a discussion on this question. Here was my reasoning:

(B) This answer choice starts from the basis of knowing that the art theft was committed by a single individual and then concludes from this that this results in a pattern of works taken that defies rational analysis. This is wrong on 2 accounts: 1. The stimulus concludes that the theft was committed by a single individual from a premise about what the art theft was not (a criterion of selection based on greatest market value.) 2. We do not know that the selection "defies rational analysis". In fact we are told that the pieces were "carefully selected". This leads me to assume that if they were carefully selected that there must have been some pattern that led the author to make this statement.
(C) I had a hard time with this answer choice because of the use of the phrase "can sometimes distinguish one type of art theft from another." The author seems to make a definitive conclusion when he/she says "It follows that the theft was specifically carried out to suit the taste . . ." This seems to be a definitive conclusion while the answer choice seems to have ambiguity in the use of "sometimes" which leaves open the possibility of "sometimes not"

Thoughts?

[ManhattanPrepLSAT1]

Have you ever noticed the difference in the following question stems?

1. Which one of the following principles would do most to justify the reasoning above?

2. The argument above conforms to which one of the following principles?

So what's the difference? The first example would be similar to a sufficient assumption in that the principle should be sufficient to justify a gap in reasoning between the evidence and the conclusion - keeping in mind that there may be subsidiary conclusion, and so the principle may bridge the gap from a premise to the subsidiary conclusion rather than establish the primary conclusion.

The second example is closer to a necessary assumption. You still want it to relate the evidence with the conclusion, but you don't need such a strong answer choice. Think of the weakness commonly associated with necessary assumptions and the strength commonly associated with sufficient assumptions. Answer choice (C) is weak because it represents a necessary assumption. And since we're dealing with the latter question type, the weakness is appropriate.

In fact you can even see that the Negation Test works here as well. If you were to negate answer choice (C), the conclusion reached in the stimulus would not be possible.

On something else you mentioned...

1. The stimulus concludes that the theft was committed by a single individual from a premise about what the art theft was not (a criterion of selection based on greatest market value.)

Careful... The stimulus does not conclude that the theft was committed by a single individual. Instead it concludes that the theft was carried out to suit the taste of some individual.

The argument does conclude that there was a specific form of art theft (one undertaken to suit the needs of some individual) from evidence about what sort of works were taken (ones that were not simply those that possessed the greatest market value). This does imply the principle expressed in answer choice (C).

Let's look at the incorrect answers though...

(A) is too strong. The argument doesn't suggest that any art theft can be classified, but does suggest that this art theft can be classified.
(B) utilizes the wrong evidence. Nowhere does the argument suggest that the theft was carried out by a single individual.
(D) utilizes the wrong evidence. Nowhere does the argument suggest that the theft was carried out with no preexisting plan for the disposition of the stolen works.
(E) reaches the wrong conclusion. It should be about whether we can identify the purpose of the art theft, not whether the theft would be particularly damaging to a museum.

Hope that helps!

[geverett]

Those are both principle support questions, but with slight differences. Interesting. You guys should release another guide where you give away more of these tricks. I love this info I am getting.

[Mab6q]

I got this question wrong because I identified it as a principle support question, in which case I thought A was a great choice. Does this question fall under the assumption family or would it be considered more of an inference question?

[maryadkins]

I would agree with Matt that this question IS a principle support question, but has the tone of a necessary assumption question over a sufficient one. In other words, you don't want an answer choice that's too extreme, like (A). Because you're not being asked to justify the argument, but you are being asked to match up what it's "appealing to" (i.e. assuming).

But the test gives us another reason to get rid of (A). We don't only have to rely on extremity.

(A) says a KNOWN individual or a KNOWN group of individuals. The conclusion of the argument just says "some individual collector." Is that collector known? No clue. Does it matter? No. The conclusion is that it must be a collector, but we still may not know who that collector is.