PT 41 Section 1 LR #10

M.M.
Posts: 381
Joined: Mon Sep 06, 2010 5:16 pm

PT 41 Section 1 LR #10

Postby M.M. » Mon Aug 27, 2012 11:59 pm

I picked D, and upon reviewing this question picked D again. I've read the explanation for it and still feel D is at least as plausible as B. No sign of the experiment lacking numbers adequate to come to a conclusion was suggested, so I find it highly improbable that, as Kaplan says,
there's a possibility that other genes may be involved in the production of UV cells—genes that, in the normal course of things, could be damaged and cause the same vision problem as did the damaged gene in the experiment.


My rationale for picking D was that damaging the gene could've caused damage to / changed something else, something that would be the real determinant of whether flies lack U vision or not and could occur independently of the gene being damaged.

Any ideas why B is definitely better than D?

TylerJonesMPLS
Posts: 74
Joined: Wed Jun 20, 2012 11:20 pm

Re: PT 41 Section 1 LR #10

Postby TylerJonesMPLS » Tue Aug 28, 2012 4:52 pm

If I understand your point, you are suggesting that the damaged gene is not necessarily the proximate cause of lack of U.V., but that the damaged gene may cause X which in turn causes lack of U. V. But X may be caused by other things than the damaged gene. So we could have Y which causes X which causes lack of U.V., assuming that Y is not another gene required for U.V. On this argument, lack of U.V. is not definitive evidence that the gene is damaged.

I think this is a good objection. It’s an interesting philosophical point. Scientists always operate on the Occam’s Razor principle- don’t multiply entities needlessly. The simplest account that takes care of all the phenomena is always the best account, even though there are an indefinate number of other possible accounts that are more complex. Buy why should the simplest account be the true one just because it is the simplest? It’s an interesting question.

But this is the LSAT, and the LSAT is much too dull for interesting questions. The stimulus just assumes that Occam’s razor is correct, even though it may not be. And, as you know, the LSAC has given itself an out by saying that you should choose the best answer, even though several answers may be good ones.

And the LSAC will say that if you use the negation test, (B) will be shown to be the best answer choice. If you negate (B), the stimulus’ conclusion definately does not follow. (B) is a necessary assumption for the argument to go through, no matter what. On the other hand, if you negate (D), the conclusion will not follow if there is an X, but it will follow if there is not an X. Since if (B) is negated that argument never goes through, but if (D) is negated that argument sometimes goes through and sometimes not, depending on whether there actuallty is an X factor or not, the LSAC will claim (B) is the best answer choice.

M.M.
Posts: 381
Joined: Mon Sep 06, 2010 5:16 pm

Re: PT 41 Section 1 LR #10

Postby M.M. » Wed Sep 05, 2012 5:56 pm

TylerJonesMPLS wrote:If I understand your point, you are suggesting that the damaged gene is not necessarily the proximate cause of lack of U.V., but that the damaged gene may cause X which in turn causes lack of U. V. But X may be caused by other things than the damaged gene. So we could have Y which causes X which causes lack of U.V., assuming that Y is not another gene required for U.V. On this argument, lack of U.V. is not definitive evidence that the gene is damaged.

I think this is a good objection. It’s an interesting philosophical point. Scientists always operate on the Occam’s Razor principle- don’t multiply entities needlessly. The simplest account that takes care of all the phenomena is always the best account, even though there are an indefinate number of other possible accounts that are more complex. Buy why should the simplest account be the true one just because it is the simplest? It’s an interesting question.

But this is the LSAT, and the LSAT is much too dull for interesting questions. The stimulus just assumes that Occam’s razor is correct, even though it may not be. And, as you know, the LSAC has given itself an out by saying that you should choose the best answer, even though several answers may be good ones.

And the LSAC will say that if you use the negation test, (B) will be shown to be the best answer choice. If you negate (B), the stimulus’ conclusion definately does not follow. (B) is a necessary assumption for the argument to go through, no matter what. On the other hand, if you negate (D), the conclusion will not follow if there is an X, but it will follow if there is not an X. Since if (B) is negated that argument never goes through, but if (D) is negated that argument sometimes goes through and sometimes not, depending on whether there actuallty is an X factor or not, the LSAC will claim (B) is the best answer choice.


My apologies for not replying more quickly. I read this a while ago and it's still bothering me. You put it exactly as I wanted to.

If you negate answer choice B, to "At least one other gene in the flies in the experiment is required for the formation of the ultraviolet vision cells." It just seems out of scope, and I wouldn't agree that the negation definitely kills the argument.

The negation of "The gene change had an effect on the flies other than the lack of ultraviolet vision cells" seems to point almost directly at my answer, whereas IMO nothing can really be concluded just from knowing another gene is involved in the (presumably many) cells of the flies.

Thanks for the answer, but I'm still not convinced at all. I just can't name something that would be the "proximate cause" of the lack of U.Vision that doesn't relate to the gene being destroyed.

I guess I can kind of see how the negation of D doesn't destroy the argument - if my mentality is that hurting the gene causes Y which causes lack of U.V., even if there is a different proximate cause for the lack of U.V. the argument could still be sound... If anyone else wants to share some input that'd be great.

User avatar
theprophet89
Posts: 46
Joined: Mon Jun 11, 2012 5:06 pm

Re: PT 41 Section 1 LR #10

Postby theprophet89 » Wed Sep 05, 2012 7:54 pm

Did this PT yesterday, also got this question wrong. The gene/vision connection isn't for sure causal, so (b) is better. I picked (d) as well.

M.M., this is a sufficient assumption question; the negation technique doesn't often work for this.

M.M.
Posts: 381
Joined: Mon Sep 06, 2010 5:16 pm

Re: PT 41 Section 1 LR #10

Postby M.M. » Wed Sep 05, 2012 8:37 pm

theprophet89 wrote:Did this PT yesterday, also got this question wrong. The gene/vision connection isn't for sure causal, so (b) is better. I picked (d) as well.

M.M., this is a sufficient assumption question; the negation technique doesn't often work for this.


???

The question stem says, "Which of the following is an assumption required for the argument?

User avatar
theprophet89
Posts: 46
Joined: Mon Jun 11, 2012 5:06 pm

Re: PT 41 Section 1 LR #10

Postby theprophet89 » Wed Sep 05, 2012 9:24 pm

M.M. wrote:
theprophet89 wrote:Did this PT yesterday, also got this question wrong. The gene/vision connection isn't for sure causal, so (b) is better. I picked (d) as well.

M.M., this is a sufficient assumption question; the negation technique doesn't often work for this.


???

The question stem says, "Which of the following is an assumption required for the argument?


My mistake.

M.M.
Posts: 381
Joined: Mon Sep 06, 2010 5:16 pm

Re: PT 41 Section 1 LR #10

Postby M.M. » Thu Sep 06, 2012 3:30 pm

theprophet89 wrote:
M.M. wrote:
theprophet89 wrote:Did this PT yesterday, also got this question wrong. The gene/vision connection isn't for sure causal, so (b) is better. I picked (d) as well.

M.M., this is a sufficient assumption question; the negation technique doesn't often work for this.


???

The question stem says, "Which of the following is an assumption required for the argument?


My mistake.


No worries!

User avatar
CyanIdes Of March
Posts: 743
Joined: Thu Aug 16, 2012 1:57 pm

Re: PT 41 Section 1 LR #10

Postby CyanIdes Of March » Thu Sep 06, 2012 6:44 pm

M.M. wrote:If you negate answer choice B, to "At least one other gene in the flies in the experiment is required for the formation of the ultraviolet vision cells." It just seems out of scope, and I wouldn't agree that the negation definitely kills the argument.


It absolutely kills the argument. The conclusion is "flies lacking UV vision must have damage to this gene" but that would be wrong if there was another gene that could equally be responsible for the formation of UV vision. In that case, the gene in question could be totally unharmed while another gene elsewhere is damaged and the flies still lacks UV vision.

M.M.
Posts: 381
Joined: Mon Sep 06, 2010 5:16 pm

Re: PT 41 Section 1 LR #10

Postby M.M. » Thu Sep 06, 2012 8:19 pm

CyanIdes Of March wrote:
M.M. wrote:If you negate answer choice B, to "At least one other gene in the flies in the experiment is required for the formation of the ultraviolet vision cells." It just seems out of scope, and I wouldn't agree that the negation definitely kills the argument.


It absolutely kills the argument. The conclusion is "flies lacking UV vision must have damage to this gene" but that would be wrong if there was another gene that could equally be responsible for the formation of UV vision. In that case, the gene in question could be totally unharmed while another gene elsewhere is damaged and the flies still lacks UV vision.


How likely do you think it is that a sufficient-for-experiment-size number of flies would all have a damaged other gene? (In asking this I assume that the experiment had large enough samples, though I'm not sure if this is justified or not. I also am assuming that the other gene wasn't damaged during the experiment.)

I sort of realize now that the "other factor" answer I picked before was wrong, because it wouldn't kill the argument (even if the damaged gene was not the proximate cause, it was still a cause) but I still don't like the credited answer.

User avatar
CyanIdes Of March
Posts: 743
Joined: Thu Aug 16, 2012 1:57 pm

Re: PT 41 Section 1 LR #10

Postby CyanIdes Of March » Thu Sep 06, 2012 10:36 pm

I think you're still reading the conclusion wrong. In the experiment it has been shown that this gene does affect UV vision. The experiments accuracy is not in question, only that the conclusion drawn from the experiment is too narrow to be accurate because of this assumption. It hasn't shown that it is the ONLY gene that affects UV vision. If a fly is missing UV vision, we can't conclusively say it has to be because this particular gene is damaged because there may be other genes responsible for UV vision as well.

User avatar
sdwarrior403
Posts: 114
Joined: Fri Aug 10, 2012 8:13 pm

Re: PT 41 Section 1 LR #10

Postby sdwarrior403 » Thu Sep 06, 2012 10:53 pm

If it is true that the damaged gene is what caused the lack of uv vision, and the rest of the genes are exactly the same as the undamaged gene group, why do we even have to worry if other genes may be required for uv vision? There is no way they are causing the lack of uv vision.

User avatar
CyanIdes Of March
Posts: 743
Joined: Thu Aug 16, 2012 1:57 pm

Re: PT 41 Section 1 LR #10

Postby CyanIdes Of March » Fri Sep 07, 2012 12:06 am

sdwarrior403 wrote:If it is true that the damaged gene is what caused the lack of uv vision, and the rest of the genes are exactly the same as the undamaged gene group, why do we even have to worry if other genes may be required for uv vision? There is no way they are causing the lack of uv vision.


Yes there is (or at least the damage/lack of other genes may also cause the same thing). This study only proves that the gene mentioned causes a lack of uv vision. It doesn't prove that other genes do not also have the same affect. It establishes a cause but it does not rule out every other potential cause.




Return to “LSAT Prep and Discussion Forum”

Who is online

Users browsing this forum: Yahoo [Bot] and 2 guests