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.