[求助]逻辑大全-3-12

shazhi

Meteorologists say that if only they could design an accurate mathematical model of the atmosphere with all its complexities, they could forecast the weather with real precision. But this is an idle boast, immune to any evaluation, for any inadequate weather forecast would obviously be blamed on imperfections in the model.

12. Which of the following, if true, could best be used as a basis for arguing against the author’s position that the meteorologists’ claim cannot be evaluated?

(A) Certain unusual configurations of data can serve as the basis for precise weather forecasts even though the exact causal mechanisms are not understood.

(B) Most significant gains in the accuracy of the relevant mathematical models are accompanied by clear gains in the precision of weather forecasts.

(C) Mathematical models of the meteorological aftermath of such catastrophic events as volcanic eruptions are beginning to be constructed.

(D) Modern weather forecasts for as much as a full day ahead are broadly correct about 80 percent of the time.

(E) Meteorologists readily concede that the accurate mathematical model they are talking about is not now in their power to construct.

Ans: B

为什么啊？不得要领？
各位NN指点啊！

dorbear

本题看似削弱题，实际是一种挑错题，其结构是：

Meteorologists：Perfect Math Model => Real Precise Weather Forecast

作者不同意这个观点但却没有给出任何削弱这个命题的有效依据，而只是把原题的逆反命题作为反对的理由。该作者的题干为：

Author: Inadequate Weather Forecast => Imperfections in the Math Model (注意不要搞反了充分和必要条件)
  
问题要求找出一个事实，来证明作者的错误。实际我们需要找到任何一个事实，只要能够帮助证明气象学家关于天气预测和数学模型的判断是错误或是正确的，就是本题的答案。

lichangmu

只要找到一种方法能够评价模型就可以了。

icare1

甲说：只要我能上树，就能把月亮摘下来。

乙说：这完全是凭空吹牛。只要你摘不下来月亮，你就会说“这都是因为我爬不上树啊”。（隐含的意思是：上树和摘月亮哪有什么关系啊。）

新闻报道说：中国有个甲，他站的高度和月亮离地球的距离居然成正比。

清楚了？

steveyangxt

二楼， 你的logo长的也忒哪个了吧，搞得俺都没能看你说的是啥就赶快跑了。

天文学家说只要有更精确的数学模型，就能更精确的预报天气。有人说他们的说法没法评估对错。

而b正是表明模型精确度和预报精确性的关系， 表明可以衡量。

kathy8446

以下是引用dorbear在2003-10-19 2:08:00的发言：
本题看似削弱题，实际是一种挑错题，其结构是：

Meteorologists：Perfect Math Model => Real Precise Weather Forecast

作者不同意这个观点但却没有给出任何削弱这个命题的有效依据，而只是把原题的逆反命题作为反对的理由。该作者的题干为：

Author: Inadequate Weather Forecast => Imperfections in the Math Model (注意不要搞反了充分和必要条件)
  
问题要求找出一个事实，来证明作者的错误。实际我们需要找到任何一个事实，只要能够帮助证明气象学家关于天气预测和数学模型的判断是错误或是正确的，就是本题的答案。

这个分析的很好啊，用一个一定成立的逆否命题是不能反驳的。

第一遍看帖子本来没注意到头像问题，结果看了steveyangxt的帖，回去再看就被晃得受不了了，结果只好复制到word再研究：P——题外话～
    

不过，还是不大明白模型和预报的精确性同时增加是怎么证明的，二者之间建立联系，不是很清楚到底怎么反驳了author的话。主要是主观上觉得author的反驳是很正确的，唉……逆否命题当然正确啦

求教！

CherrieLi

Questions 12-13 are based on the following.

Meteorologists say that if only they could design an accurate mathematical model of the atmosphere with all its complexities, they could forecast the weather with real precision. But this is an idle boast, immune to any evaluation, for any inadequate weather forecast would obviously be blamed on imperfections in the model.

12.Which of the following, if true, could best be used as a basis for arguing against the author’s position that the meteorologists’ claim cannot be evaluated?

(A) Certain unusual configurations of data can serve as the basis for precise weather forecasts even though the exact causal mechanisms are not understood.

(B) Most significant gains in the accuracy of the relevant mathematical models are accompanied by clear gains in the precision of weather forecasts.

(C) Mathematical models of the meteorological aftermath of such catastrophic events as volcanic eruptions are beginning to be constructed.

(D) Modern weather forecasts for as much as a full day ahead are broadly correct about 80 percent of the time.

(E) Meteorologists readily concede that the accurate mathematical model they are talking about is not now in their power to construct.

答案B, 请问要如何排除其它选项呢?

13.Which of the following, if true, would cast the most serious doubt on the meteorologists’ boast, aside from the doubt expressed in the passage above?

(A) The amount of energy that the Earth receives from the Sun is monitored closely and is known not to be constant.

(B) Volcanic eruptions, the combustion of fossil fuels, and several other processes that also cannot be quantified with any accuracy are known to have a significant and continuing impact on the constitution of the atmosphere.

(C) As current models of the atmosphere are improved, even small increments in complexity will mean large increases in the number of computers required for the representation of the models.

(D) Frequent and accurate data about the atmosphere collected at a large number of points both on and above the ground are a prerequisite for the construction of a good model of the atmosphere.

(E) With existing models of the atmosphere, large scale weather patterns can be predicted with greater accuracy than can relatively local weather patterns.

答案B, 请问为什么呢? 其它选项应如何排除?