GMAT 逻辑分析题 (5)

courtdancer

Nothing special here. If you say something is good or bad, you are making a value judgement. That's it.

-- by 会员 sdcar2010 (2011/8/20 10:30:56)

sdcar2010，有个问题请教，关于这道题想了挺久依旧不得其法，请允许我用中文表述～
逻辑链跟您写的一样，没什么疑问
Conclusion: The intentions of CDer’s cannot be more bad than good.  This is a value judgement.
Evidence: The above conclusion is built on an argument that if we believe otherwise, i.e., if we believe that the intentions are more bad than good, then the consequence of such a belief would be very negative.  Hence, this deleterious belief cannot be true.
我觉得这道题使用的逻辑方法有点类似“反证法”
要证明的是good intentions > bad ones
argument逻辑链如下
IF bad intentions>good ones反证
THEN stoping trusting each other
IF we stop trusting each other
THEN  no on-line community, ChaseDream.com included, can survive
但是现在ChaseDream.com survive，所以最开始的假设IF bad intentions>good ones就是错误的，于是就证明了good intentions > bad ones
暂且不管结论在常识方面正确与否，但是我感觉似乎逻辑链是没有问题的（这里我跟前面Kevin的意见不一致，我觉得并不是像Kevin所说的not A→B推出A→not B导致错误，这里很好的运用了逆否命题，即非A→B如果正确，那么非B→A也是正确的——A为good intentions > bad ones，非A为bad intentions>good ones；B为  no on-line community, ChaseDream.com included, can survive，非B为ChaseDream.com survive）
所以我感觉整个命题似乎在逻辑上没有漏洞。。。
请问我的分析在哪里出问题了？谢谢

courtdancer

我感觉有点像这道题
2) Some people have been promoting a new herbal mixture as a remedy for the common cold. The mixture contains, among other things, extracts of the plants purple cone-flower and goldenseal. A cold sufferer, skeptical of the claim that the mixture is an effective cold remedy, argued, “Suppose that the mixture were an effective cold remedy. Since most people with colds wish to recover quickly, it follows that almost everybody with a cold would be using it. Therefore, since there are many people who have colds but do not use the mixture, it is obviously not effective.”

Which one of the following most accurately describes the method of reasoning the cold sufferer uses to reach the conclusion of the argument?

(A) finding a claim to be false on the grounds that it would, if true, have consequences that are false (A)
(B) accepting a claim on the basis of public opinion of the claim
(C) showing that conditions necessary to establish the truth of a claim are met
(D) basing a generalization on a representative group of instances
(E) showing that a measure claimed to be effective in achieving a certain effect would actually make achieving the effect more difficult

The argument goes like the following:
Premise:
1) If the mixture were an effective cold remedy (the claim); people who have cold would have used the mixture (the consequence).
2) But there are many people who have colds but do not use the mixture (the consequence is false).
Conclusion:
The mixture is obviously not effective (the claim is false).