The difficulty with the proposed high-speed train line is that a used plane can be bought for one-third the price of the train line, and the plane, which is just as fast, can fly anywhere. The train would be a fixed linear system, and we live in a world that is spreading out in all directions and in which consumers choose the freewheel systems (cars, buses, aircraft), which do not have fixed routes. Thus a sufficient market for the train will not exist.
Which of the following, if true, most severely weakens the argument presented above?
112. The difficulty with the proposed high-speed train line is that a used plane can be bought for one-third the price of the train line, and the plane, which is just as fast, can fly anywhere. The train would be a fixed linear system, and we live in a world that is spreading out in all directions and in which consumers choose the free-wheel systems (cars, buses, aircraft), which do not have fixed routes.Thus a sufficient market for the train will not exist.
Which of the following, if true, most severely weakens the argument presented above?
(A) Cars, buses, and planes require the efforts of drivers and pilots to guide them, whereas the train will be guided mechanically.
(B) Cars and buses are not nearly as fast as the high-speed train will be.
(C) Planes are not a free-wheel system because they can fly only between airports, which are less convenient for consumers than the high-speed train’s stations would be.
(D) The high-speed train line cannot use currently underutilized train stations in large cities.
(E) For long trips, most people prefer to fly rather than to take ground-level transportation.
这题的逻辑链应该是:
Premise 1: used plane has lower price than train line, and plane can fly anywhere
Premise 2: train has fixed linear system, but we live in a free-wheel systems
Conclusion: a sufficient market for the train will not exist.
文中从premise推出conclusion,作者用train line和plane做比较,认为plane可以fly anywhere但是train是fixed line,以此说明plane比train有market,推出train的sufficient market不存在。
其实在推理中存在一个assumption:plane has free-wheel system (plane can fly anywhere)。正因为plane has free-wheel system, but train has fixed line system, 所以plane比train强。
C选项的weaken方式其实是exposes a faulty assumption. 如果说Planes are not a free-wheel system,那我们的assumption不成立,assumption不成立就说明想用是否是free-wheel system来推出sufficient market这个推导是不成立的.
所以这题其实并不是对premise的削弱,而是对其中的assumption进行削弱。只是需要我们把这个assumption理出来。
嘿嘿 谢谢海绵~ 我这两天都没有上 所以才看到
你说的意思 我明白啦 我当时大概也是像你这么推理的
但是啊 我这题最大的问题在于 这个"airecraft belongs to the free-line system"并不是hidden的呀!因为原文中在premise中实在的说了"in which consumers choose the free-wheel systems (cars, buses, aircraft)"所以我才疑问,这怎么否定原文给出的事实呢!(是不是好钻牛角尖T T)