SDCAR2010【逻辑入门】（九）Flaw (part 1)

perain

Here is another flaw question:
Joseph: My encyclopedia says that the mathematician Pierre de Fermat died in 1665 without leaving behind any written proof for a theorem that he claimed nonetheless to have proved. Probably this alleged theorem simply cannot be proved, since---as the article points out---no one else has been able to prove it. Therefore it is likely that Fermat was either lying or else mistaken when he made his claim.
Laura: Your encyclopedia is out of date. Recently someone has in fact proved Fermat’s theorem. And since the theorem is provable, your claim---that Fermat was lying or mistaken---clearly is wrong.

Which one of the following most accurately describes a reasoning error in Laura’s argument?

(A) It purports to establish its conclusion by making a claim that, if true, would actually contradict that conclusion.
(B) It mistakenly assumes that the quality of a person’s character can legitimately be taken to guarantee the accuracy of the claims that person has made.
(C) It mistakes something that is necessary for its conclusion to follow for something that ensures that the conclusion follows.
(D) It uses the term “provable” without defining it.
(E) It fails to distinguish between a true claim that has mistakenly between believed to be false and a false claim that has mistakenly been believed to be true.

-- by 会员 sdcar2010 (2011/6/29 12:09:21)

quite difficult.... the options are quite hard to understand.....however I think the answer is E.  
Laura made the conclusion based on the assumption that the Pierre de Fermat was telling the truth so long as the theorem can be proved. But what if Pierre de Fermat indeed lied?

jaze

Here is another flaw question:
Joseph: My encyclopedia says that the mathematician Pierre de Fermat died in 1665 without leaving behind any written proof for a theorem that he claimed nonetheless to have proved. Probably this alleged theorem simply cannot be proved, since---as the article points out---no one else has been able to prove it. Therefore it is likely that Fermat was either lying or else mistaken when he made his claim.
Laura: Your encyclopedia is out of date. Recently someone has in fact proved Fermat’s theorem. And since the theorem is provable, your claim---that Fermat was lying or mistaken---clearly is wrong.

Which one of the following most accurately describes a reasoning error in Laura’s argument?

(A) It purports to establish its conclusion by making a claim that, if true, would actually contradict that conclusion.
(B) It mistakenly assumes that the quality of a person’s character can legitimately be taken to guarantee the accuracy of the claims that person has made.
(C) It mistakes something that is necessary for its conclusion to follow for something that ensures that the conclusion follows.
(D) It uses the term “provable” without defining it.
(E) It fails to distinguish between a true claim that has mistakenly between believed to be false and a false claim that has mistakenly been believed to be true.

-- by 会员 sdcar2010 (2011/6/29 12:09:21)

premise:
no written proof claimed to have proved the theory.
no one else has been able to prove it
conclusion:
either lying or mistakenly

Laura's reasoning
provable --> not (either lying or mistakenly)
that is
A -> B
Laura's reasoning is   not A  --> not B

I would vote for C
but i understand those options poorly.
I do not make sense what option E is talking about.

Kb24

agree C. Saw this one in LSAT test. E is just too far away.

sdcar2010

At present the Hollywood Restaurant has only standard-height tables. However, many customers come to watch the celebrities who frequent the Hollywood, and they would prefer tall tables with stools because such seating would afford a better view of the celebrities. Moreover, diners seated on stools typically do not stay as long as diners seated at standard-height tables. Therefore, if the Hollywood replaced some of its seating with high tables and stools, its profits would increase.


The argument is vulnerable to criticism on the grounds that it gives reason to believe that it is likely that

(A) some celebrities come to the Hollywood to be seen, and so might choose to sit at the tall tables if they were available
(B) the price of meals ordered by celebrities dining at the Hollywood compensates for the longer time, if any, they spend lingering over their meals
(C) a customer of the Hollywood who would choose to sit at a tall table would be an exception to the generalization about lingering
(D) a restaurant's customers who spend less time at their meals typically order less expensive meals than those who remain at their meals longer
(E) with enough tall tables to accommodate all the Hollywood's customers interested in such seating, there would be no view except of other tall he support

I really do not quite understand why the OA is C
My reasoning is this:
Background. However, premise, and intermediate conclusion because premise. Moreover, premise.
Therefore, premise, conclusion.

The author draws his conclusion based on two premise: one is the change will attract more people, and the other is people who seat at high tables will stay less time. That is, more people, higher fluidity.

(C) a customer of the Hollywood who would choose to sit at a tall table would be an exception to the generalization about lingering

I do not understand the relation between what option c says and what the premises says.
If the exception to the generalization about lingering can constrain people to seat at high table, then i know the Option can really weaken the conclusion. But what is reaction of people who would choose to sit at a tall table is not mentioned in the conclusion. I thought this answers is a relevant one.

-- by 会员 jaze (2011/6/30 10:50:14)

Good analysis. This is a tricky question. The assumption that those who come to see celebrities and sit on the high stool would stay longer is never mentioned in the stimulus, but would be correct based on COMMON SENSE. It is a stretch, but still a reasonable stretch.

sdcar2010

Here is another flaw question:
Joseph: My encyclopedia says that the mathematician Pierre de Fermat died in 1665 without leaving behind any written proof for a theorem that he claimed nonetheless to have proved. Probably this alleged theorem simply cannot be proved, since---as the article points out---no one else has been able to prove it. Therefore it is likely that Fermat was either lying or else mistaken when he made his claim.
Laura: Your encyclopedia is out of date. Recently someone has in fact proved Fermat’s theorem. And since the theorem is provable, your claim---that Fermat was lying or mistaken---clearly is wrong.

Which one of the following most accurately describes a reasoning error in Laura’s argument?

(A) It purports to establish its conclusion by making a claim that, if true, would actually contradict that conclusion.
(B) It mistakenly assumes that the quality of a person’s character can legitimately be taken to guarantee the accuracy of the claims that person has made.
(C) It mistakes something that is necessary for its conclusion to follow for something that ensures that the conclusion follows.
(D) It uses the term “provable” without defining it.
(E) It fails to distinguish between a true claim that has mistakenly between believed to be false and a false claim that has mistakenly been believed to be true.

-- by 会员 sdcar2010 (2011/6/29 12:09:21)

premise:
no written proof claimed to have proved the theory.
no one else has been able to prove it
conclusion:
either lying or mistakenly

Laura's reasoning
provable --> not (either lying or mistakenly)
that is
A -> B
Laura's reasoning is   not A  --> not B

I would vote for C
but i understand those options poorly.
I do not make sense what option E is talking about.

-- by 会员 jaze (2011/6/30 14:11:36)

Very good analysis. This is the right way to tackle the questions which involve formal logic. Well-done.

sdcar2010

Here is another flaw question:
Joseph: My encyclopedia says that the mathematician Pierre de Fermat died in 1665 without leaving behind any written proof for a theorem that he claimed nonetheless to have proved. Probably this alleged theorem simply cannot be proved, since---as the article points out---no one else has been able to prove it. Therefore it is likely that Fermat was either lying or else mistaken when he made his claim.
Laura: Your encyclopedia is out of date. Recently someone has in fact proved Fermat’s theorem. And since the theorem is provable, your claim---that Fermat was lying or mistaken---clearly is wrong.

Which one of the following most accurately describes a reasoning error in Laura’s argument?

(A) It purports to establish its conclusion by making a claim that, if true, would actually contradict that conclusion.
(B) It mistakenly assumes that the quality of a person’s character can legitimately be taken to guarantee the accuracy of the claims that person has made.
(C) It mistakes something that is necessary for its conclusion to follow for something that ensures that the conclusion follows.
(D) It uses the term “provable” without defining it.
(E) It fails to distinguish between a true claim that has mistakenly between believed to be false and a false claim that has mistakenly been believed to be true.

-- by 会员 sdcar2010 (2011/6/29 12:09:21)

quite difficult.... the options are quite hard to understand.....however I think the answer is E.  
Laura made the conclusion based on the assumption that the Pierre de Fermat was telling the truth so long as the theorem can be proved. But what if Pierre de Fermat indeed lied?

-- by 会员 perain (2011/6/30 11:08:06)

Nice try. The major reason against your reasoning is that an assumption is not a claim. A claim has to be stated in the stimulus.

qiushuan

If the law punishes littering, then the city has an obligation to provide trash cans. But the law does not punish littering, so the city has no such obligation.
Which one of the following exhibits a flawed pattern of reasoning most similar to that in the argument above?
(A) If today is a holiday, then the bakery will not be open. The bakery is not open for business. Thus today is a holiday.
(B) Jenny will have lots of balloons at her birthday party. There are no balloons around yet, so today is not her birthday.
(C) The new regulations will be successful only if most of the students adhere to them. Since most of the students will adhere to those regulations, the new regulations will be successful.
(D) In the event that my flight had been late, I would have missed the committee meeting. Fortunately, my flight is on time. Therefore, I will make it to the meeting.
(E) When the law is enforced, some people are jailed. But no one is in jail. So clearly the law is not enforced.

why the answer is D? I choose C. Because I think other are follow the pattern if A, Then B. If not A, then not B. Can u explain why i am wrong? thxs a lot!!

sdcar2010

(C) The new regulations will be successful only if most of the students adhere to them. Since most of the students will adhere to those regulations, the new regulations will be successful.
If successful, then adhere. If adhere, then successful.

(D) In the event that my flight had been late, I would have missed the committee meeting. Fortunately, my flight is on time. Therefore, I will make it to the meeting.
If late, then miss. If not late, then not miss.

MarsTOF

mistakes a condition sufficient for bringing about a result for a condition necessary for doing so

The above flaw is demonstrated in the following argument:
Premise: If event A, then event B
Conclusion: If event B, then event A.

不是很理解这个例子，我觉得你举得例子是原因 结果的互换？  跟充分和必要条件的混淆不是一个意思啊？  请指教~

verawu

请问一下，我是刚开始GMAT的，逻辑不太懂。
At present the Hollywood Restaurant has only standard-height tables. However, many customers come to watch the celebrities who frequent the Hollywood, and they would prefer tall tables with stools because such seating would afford a better view of the celebrities. Moreover, diners seated on stools typically do not stay as long as diners seated at standard-height tables. Therefore, if the Hollywood replaced some of its seating with high tables and stools, its profits would increase.

The argument is vulnerable to criticism on the grounds that it gives reason to believe that it is likely that

(A) some celebrities come to the Hollywood to be seen, and so might choose to sit at the tall tables if they were available
(B) the price of meals ordered by celebrities dining at the Hollywood compensates for the longer time, if any, they spend lingering over their meals
(C) a customer of the Hollywood who would choose to sit at a tall table would be an exception to the generalization about lingering
(D) a restaurant's customers who spend less time at their meals typically order less expensive meals than those who remain at their meals longer
(E) with enough tall tables to accommodate all the Hollywood's customers interested in such seating, there would be no view except of other tall he support


这个题目不太能理解，求指教。