Q15 - J. J. Thomson, the discoverer

[ManhattanPrepLSAT1]

joshmercer80 wrote:

Not sure which test this one comes from either.

My thought process:
A - nope, has nothing to do with how famous he was
B - Hmm, well if I can prove they had creative research after they were trained then they certainly can't have acquired the skills for creative research. Maybe.
C - Hmm, another good one. Obviously if they all had the skills for creative research before they were trained by Thomson, they he wouldn't have taught them those skills. However, if only one student had lacked such skills prior to Thomson's tutelage, this would not be enough in my mind to any correlation.
D - Habits? Other fields? What the...? Next.
E - Not really what I'm looking for. No.

So I was torn between B and C and guessed wrong. Correct answer being C. Granted looking now, I can see that all it takes is one student to acquire the skills from Thomson and we have a good argument. At the same time I thought that showing that they ended up with the skills was also an necessity for an argument. Please oh wise Atlas LSAT gods, distill upon me your wisdom. Thank you.

[ManhattanPrepLSAT1]

You're right where the test-writer expected you to end up, and where most people end up. A good score on the LSAT usually comes down to making the right call when you're down to two answer choices.

There are many tools at our disposal for eliminating that final answer choice, but the most important is fully understanding the scope of the question type. This is a necessary assumption question, so we can apply the negation test. We'll take the two answer choices we like and negate them. The negation of one of them should destroy the conclusion, and that's the correct answer. If an answer choice was needed for the argument to work, then without it, the conclusion should be destroyed.

If we negate answer choice (B).

Not all the scientists trained by J. J. Thomson were renowned for their creative scientific research.

The conclusion could still be true, so this was not a necessary assumption of the argument.

If we negate answer choice (C).

All of the eminent scientists trained by J. J. Thomson were creative researchers before coming to study with him.

This would completely destroy the conclusion that they learned as a result of J.J. Thomson's teaching. So this is a necessary assumption of the argument, and the correct answer choice.

So, while answer choices (B) and (C) strengthen the argument, only answer choice (C) is a necessary assumption. Does that help clear things up joshmercer80? Let me know if you still need a bit more help on this one!

[joshmercer80]

Thank you for your answer. Now, let me make sure I understand this elimination by negation technique. I want to make sure that I end up with the correct modified answer in order to see if the conclusion gets destroyed by negation.

With answer B, in my mind if I were to simply toss in a negative (how I would negate something in my mind or by my definition), I would have said "None of the scientists trained by J.J. Thomson were renowned for their creative scientific research." You put, "Not all..." So do I add in a "not" or remove one to negate? In my mind the opposite of all would have been none which surely would have destroyed the conclusion. If none of them showed any signs of having creative research skills, then Thomson didn't teach them those skills.

With answer C, you put, "All... were creative researchers...". Removing the "not" and changing "At least one" to "All". In my mind I would have just changed "was not" to "was" and given me a scenario in which the conclusion would not have been affected.

I just want to make sure that I can use the same elimination technique when I need to and end up with the correct answer. Thank you for your help and patience with these questions I problems I post.

[ManhattanPrepLSAT1]

Good question.

I start by looking for quantification

ALL
MOST
SOME
NONE

the opposite of

ALL is NOT ALL
MOST is MOST ARE NOT
SOME is NONE
NONE is SOME

if I see a conditional relationship

A ---> B

B is required for A to occur. I negate that by saying that B is not required for A to occur. Or I could say it this way A can occur, even if B does not occur.

if I don't see quantification or a conditional relationship I just negate the verb

The car is driving fast, negated would be, The car is not driving fast.

Be careful not to double negate. Leave the subject alone and only negate once.

The car that is driving fast will get a ticket, negated would be, The car that is driving fast will not get a ticket. You would not want to say, the car that is not driving fast will not get a ticket.

So, here's my mental contortions on answer choice (C) to make it easier to read. If I had made a literal negation it would have been confusing.

At least one was not a creative researcher

became

None of them was not a creative researcher.

I got rid of the double negative and interpreted it as

All of them were creative researchers.

Good luck! And always feel free to email me with any statements you need help negating.

matt@atlaslsat.com

[WaltGrace1983]

I think the easy way to eliminate (B) would be to think about the word "renowned." Do they absolutely have to be renowned for their creative scientific research? Not really, no; they don't have to be famous for what they have done. They just had to have done it.

Yet to play devil's advocate I have a question about (C). Who's to say that any of J. J.'s students actually became creative researchers? I feel like this argument is missing a sentence such as, "many of J. J.'s students ended up becoming world-famous creative researchers. This shows that the skills needed for creative research can be taught and learned." After all, maybe 3 of his 100 students were creative researchers before studying under J.J. but maybe those same 3 of his 100 students were creative researchers after. Maybe they learned nothing.

Does anyone have an answer for this?

I also thought that (D) was a more tempting answer choice. In my head, I was thinking that if these skills were necessary for other fields then maybe they already had the skills, etc. etc. etc. but I realized that I was making too many extraneous assumptions and it was really getting at the gap that (C) was getting at anyway.

[christine.defenbaugh]

Thanks for posting WaltGrace1983!

Multiple reasons why (B) is wrong
You are spot on. (B) is wrong for two separate reasons. If we overlook the 'renowned' issue, then Matt's attack above on the quantifiers still gets us home. But if we struggled with the quantifiers, you are absolutely correct that while the argument needs some of these guys to be creative researchers, we don't need them to be renowned for it.

Additional Assumptions the Argument Needs
The issue you are raising about (C) is essentially that it is not sufficient to make the argument work. And you're right. But remember, we aren't looking for a sufficient assumption - only a necessary one.

This argument TOTALLY assumes that these eminent scientists went on to do creative research. A totally valid answer choice here might have been something like "At least one of the eminent scientists trained by Thomson went on to do creative research." But the fact that we need this other assumption also does not diminish our need for the assumption in (C). And you're right, then we also need yet another assumption that there is overlap between those who weren't creative researchers before and those who became creative researchers after.

When you feel like the argument is missing something, the exercise you are involved in is uncovering what necessary assumptions it makes. So, kudos! Just remember that arguments can have myriad necessary assumptions, and the answer choice often only addresses one of them, and that's okay.

It is absolutely critical that on a Necessary Assumption question you do not left sufficiency analysis sneak in, and vice versa.

Does that help a bit?