#17 - Lawyer: A body of circumstantial evidence is like a

[alee]

Hi guys,

This question is about Preptest 53, Section III ,Question 17. I understood the stimulus as follows:

Prem: A body of circumstantial evidence is like a rope
Prem: Each item of evidence = strand of that rope, additional pieces of evidence strengthen the body of evidence, and if 1 strand breaks, the rope is not broken or its stregth must diminished.

I am having trouble eliminating Contenders and justifying the correct answer. Is the following rationale correct?

-Rule out C because the argument explicitly defined the scope of its conclusion to when 'a few items' are discredited, and it says nothing about when 'many items' are discredited
-Rule out E because the conclusion about the effect of a 'few items being discredited' is not mentioned elsewhere in the argument (the closest thing is 'if *one* strand breaks the strength of the rope is not much dminished, however this refers to only *one* strand/item of evidence being discredited, not *many* as the conclusion refers to)
-Rule out B because the argument makes no such presumption

Then I have real trouble distinguishing between D and A. (D) is definitely *partially correct* in that the argument proceeds by analogy. However is it correct to rule it out on the basis that it is not the case that the argument 'offers no indications of whether the 2 types of things being compared share any similarities?'

Finally, how do we justify 'A'? I proceeded by using the technique we were taught for assumption questions: let it be true and see if this makes the conclusion false. If it is true, than the conclusion may be false because if amongst the 'few items' that are discredited are items that are 'significantly more critical', the conclusion that the overall strength of the evidence is unaffected is untrue.

Sorry, long question, but I am trying to get a handle of the technique taught in the logial reasoning bible, applying them etc... Thanks!

[Steve Stein]

Thanks for your question. On that one, as you point out, the lawyer compares a case built on circumstantial evidence with a rope, saying a discrediting a few pieces of circumstantial evidence would be ok, in the same way that a rope can survive losing a few strands. The problem with this argument is that not all circumstantial evidence is of equal value; if even a single vital piece of evidence is discredited, that could completely undermine a case.

Correct answer choice A accurately describes the problem: the lawyer appears to believe that, like the identical countless strands of a rope, all pieces of evidence are of equal weight and value.

(as an aside, you mentioned that you used a technique for Assumption questions--but this is a Flaw question so that approach cannot be effectively applied in this context. I'd suggest taking another look at the sections of the LRB that deal with Assumptions and Flaws)

Let me know whether all that's clear--thanks!

~Steve

[alee]

Yes, thanks Steve for pointing that out.... I think i have been treating flaw and assumption questions as the same, which can be dangerous as you indicated! I'll get on to it today, thanks for the ongoing help, you guys do a great job.

[SLF]

I sincerely appreciate everyone's patience with me. With each response, my understanding expands...so thanks to everyone.

Allow me to bring in another example: LSAT #53, Section #3, Question #17...

As I processed this question, I struggled with selecting between A, C, and E. So, would someone kindly articulate how they would process these three answer choices and ultimately select a final answer choice?

[Dave Killoran]

Hi SLF,

(A), (C), and (E) are all very different answers. Let me eliminate answer choice (E) right away because this isn't a circular argument. The premises are different from the conclusion, and the premises do not assume the conclusion. So, that one is gone.

The question with (C) is two-fold: did the author fail to consider it, and did he need to consider it? First, the consideration given was to a few items being discredited, and that not being enough to change the basic strength. That doesn't immediately imply anything about what happens when many strands break, however. So, then, if it wasn't considered, was it a flaw to not consider it? the answer to that is no, because the author is making a point about individual strands, and what occurs with one strand and a few strands. In other words, the author had no obligation to address this issue in the argument.

That brings us to (A). This is the right answer, and you can see how it reveals the flaw in the argument. The author assumes that removing just a few stands is similar to removing just a few minor pieces of evidence. But this is where the analogy the lawyer has used fails: not all strands (pieces of evidence) in a case are of equal value (and that includes those that are circumstantial). Some are more important than others, and so this is a problem because if the two or three pieces removed were critical pieces, that would bring into question the conclusion.

Going back to my point about outside information in my prior post, the question might arise as to how much you are supposed to know about all this. LSAC would say that understanding cases and evidence in a basic fashion is something you are assumed to know. The fact that some pieces of evidence are more important than others is considered public domain knowledge, and so you are expected to see that the rope analogy has weaknesses when it is made (and if you didn't, the answer are there to help suggest possible problems).

The last point here is that between (A) and (C), note that (C) rests on taking a point in the argument and applying it to an expanded case. (A) rests on whether the point int he argument is actually accurate. That's a big difference, and one more that makes (A) attractive.

Thanks!

[SLF]

That's an excellent response. Thanks so much.

[srcline@noctrl.edu]

Hello Dave,

So I'm just trying to understand your reasoning on why C is incorrect, The main difference between this a.c. an the conclusion is the words many and few?

Whereas A is saying that the author fails to take into account that there may be one piece of evidence that could dismantle the lawyer entire argument even if some parts are not discredited?

Thankyou
Sarah

[Jonathan Evans]

Hi, Sarah,

Good question. In the argument, the author does not address what would happen if "many" items of a body of circumstantial evidence are discredited. She only addresses what will happen if a "few" items are discredited. Since the argument concerns only what happens when a few items are discarded, the answer that treats of the effect of the invalidation of "many" items is outside the scope of this argument.

[PeterC123]

Hi,

I thought that many is the same as some (a few), so even though the stimulus talks about "a few" I did not immediately get rid of answer C just because it had the word many in it. I choose A during the prep test but during review C is proving hard to get rid of.

I think getting rid of C purely because of the many vs a few is a flimsy reason, and applying the same reasoning for future questions will be extremely difficult. So can anyone one give me another reason?

Thanks in advance!

[Francis O'Rourke]

Hi Peter,

I understand that the difference between few and many is troubling for you, but you absolutely need to be aware of this distinction to understand the scope of future arguments. If you don't feel like few and many are distinct terms, then I would highly recommend reading the following article: LSAT Quantity Terminology

So why does switching from few to many make a difference in this question? The speaker was making a claim about what occurs after "even a few items" of circumstantial evidence are discredited. Let's assume that there are 100 items of evidence at this trial. Since the speaker emphasizes even a few, how many items, maximum, could we imagine are discredited if you read in a newspaper that the defense discredited a few items of evidence? I would put that number around 4 to 8.

In this same case, how many would you assume if you were to read in a trusted newspaper that many items of evidence were discredited? I would personally put the figure at somewhere between 10 and 45. Any more and I would expect to read about half or most. Any fewer and it would be disingenuous to report many.

Our upper and lower bounds might vary, and they will change depending on the total number we are considering, but everyone agrees that many communicates something different from a few.

So it might be correct to say that the speaker never addressed the effects of 40 out of a total of 100 of the items of circumstantial evidence being discredited. This however would matter for an argument that only purports to show what happens if only "even a few" items are discredited.