GMAT 逻辑分析题 (5)

sdcar2010

When people submit their posts to ChaseDream.com, their intentions cannot be more bad than good.Otherwise, as members of a close-knit on-line community, we would stop trusting each other. However, no on-line community, ChaseDream.com included, can survive without mutual trust among its members.

The argument is most vulnerable to which one of the following criticisms?

(A) It neglects the possibility that a true belief can have unexpected harmful consequences.

(B) It mistakenly assumes that if two different claims cannot be true at the same time, then both claims cannot be false at the same time.

(C) It questions the validity of a claim by calling into question the intentions of those who make the claim.

(D) It assumes without justification that whenever two possible outcomes are possible, inevitably the more negative one will occur.

(E) It gives no reason to believe that a statement that is true of a given online community is also true of any other online community.

kevin0214

选B

nrfujian

选e

sdcar2010

When people submit their posts to ChaseDream.com, their intentions cannot be more bad than good. Otherwise, as members of a close-knit on-line community, we would stop trusting each other. However, no on-line community, ChaseDream.com included, can survive without mutual trust among its members.

The argument is most vulnerable to which one of the following criticisms?

(A) It neglects the possibility that a true belief can have unexpected harmful consequences.

(B) It mistakenly assumes that if two different claims cannot be true at the same time, then both claims cannot be false at the same time.

(C) It questions the validity of a claim by calling into question the intentions of those who make the claim.

(D) It assumes without justification that whenever two possible outcomes are possible, inevitably the more negative one will occur.

(E) It gives no reason to believe that a statement that is true of a given online community is also true of any other online community.

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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.

We need to weaken this argument by one of the answer choices.

(A) Correct. The key here is to identify why the argument is flawed.  The author states that if we do not believe that member's intentions are more good than bad, this FALSE belief would have harmful consequences. From this statement, the author goes further to conclude that the FALSE belief is FALSE. In layman’s language, something is bad because it leads to harmful end results. What the author is assuming is that in the case of a TRUE belief, i.e., we believe that member's intention are more good than bad, none of the bad consequence would happen!  Therefore, the TRUE belief is TRUE.  But there is no evidence in the argument to back up this assumption. So the argument is vulnerable to the objection that the author does not present any evidence which prevents a true belief from having dire consequences.

(B) Incorrect. The argument focuses on the consequence of certain beliefs. But there is no mentioning of the possibilities in which the two beliefs could be both true or both wrong.  So (B) is out of scope.

(C) Incorrect. The argument does challenge the truth of a claim that CDer’s intentions can be more bad than good. But this is a hypothetical claim behind which stands nobody.  So (C) is irrelevant.

(D) Incorrect. Along the reasoning process, the author deals with situations having two possible outcomes.  For example, an on-line community ChaseDream.com can survive or cannot survive.  But the author does not assume that the most negative outcome (not surviving) would be certain. On the contrary, the author assumes that the more positive outcome (surviving) will prevail. So (D) is a 180 wrong answer.

(E) Incorrect. The argument is a general statement about members of ChaseDream.com and their beliefs.  Furthermore the argument is built on the effects of those beliefs on the survival of the on-line community composed of those members. If anything, the author believes that what happens to other on-line communities will be applicable to ChaseDream.com. So the inference is from what is true about many other groups to what is about a particular group. So the argument is not vulnerable to the criticism detailed in (E).

kevin0214

谢谢~懂了，not A→B不代表A→not B, 我没注意到true belief是 their intentions can be more bad than good的意思，我以为是一种general的描述，说的是一种“真实的信仰”之类的东西。

sdcar2010

It fooled me, too.

corrine90

I don't quite understand the meaning of the conclusion "The intentions of CDer’s cannot be more bad than good.  This is a value judgement." Could you explain it to me? Thank you.

sdcar2010

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

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).