请问如何理解Lawyer NN讲的weaken 方法中的“条件型结论”

Lawyer NN讲过“条件型结论：结论带条件（即为充分必要）。WEAKEN的方法显示充分条件成立，必要条件可以不成立。或举反例，或提供有关信息。”

可是我在总结OG的时候怎么找不到这种类型的题呢？是不是因为我太笨拉，还是我没有理解这种方法呢？想来想去，勉强把OG59分作这一类：

不太同意.OG96不是条件型结论。条件型结论标志是if ...then..削弱方式为承认if成立,而then不成立.

96题是一般的削弱.直接作用于结论.这种削弱是可以用反对前提的方法.也就是OG96的方法.而条件型结论是绝对不可以用反对前提的方法的.即不能反对充分条件。

我也是体会了很久才明白了NN说的条件形结论是什么，其实OG里面有很多这种题的，比如说：OG12，36，75，80，81等等都是，他们共同的特点就是结论是“if..., ...”的结构， 对这种削弱时不能削弱if的内容，而只能削弱if的充分性，削弱的答案就是说if的内容成立的时候，结果不成立。那OG12做例子：

12.

The fewer restrictions there are on the advertising of legal services, the more lawyers there are who advertise their services, and the lawyers who advertise a specific service usually charge less for that service than lawyers who do not advertise. Therefore, if the state removes any of its current restrictions, such as the one against advertisements that do not specify fee arrangements, overall consumer legal costs will be lower than if the state retains its current restrictions.

A. The state has recently removed some other restrictions that had limited the advertising of legal services.

B. The state is unlikely to remove all of the restrictions that apply solely to the advertising of legal services.

C. Lawyers who do not advertise generally provide legal services of the same quality as those provided by lawyers who do advertise.

D. Most lawyers who now specify fee arrangements in their advertisements would continue to do so even if the specification were not required.

E. Most lawyers who advertise specific services do not lower their fees for those services when they begin to advertise.

Since A does not relate the recent removal of restrictions to changes in consumer legal costs, it alone does not weaken the argument. Since the argument is unconcerned with whatever restrictions remain in effect but focuses only on those that will be removed, B does not weaken the argument. C and D are irrelevant to an evaluation of the argument, which is concerned with cost considerations, not with the quality of legal services or the content of lawyers’ advertisements.

结论时在if the state retains its current restrictions的情况下overall consumer legal costs will be lower 成立，削弱说在if the state retains its current restrictions成立的情况下，overall consumer legal costs will be lower 不一定成立
而常常有混淆选项就是说在没有if the state retains its current restrictions的情况下，overall consumer legal costs will be lower 也成立，这种选项其实无法削弱原结论

有道理有道理，楼上的gg

等偶再好好体会一下再来汇报

来汇报今天的体会：

在文章题目没有明确以“If"开头的结论时，也有很多是通过否定隐藏的必要条件来削弱的。例如OG96

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. C

(E) For long trips, most people prefer to fly rather than to take ground-level transportation.

题目说飞机被preferred,因为它比火车自由。所以题目隐藏的必要条件就是飞机比火车自由。C选项攻击了这个必要条件，说飞机不必火车自由，从而削弱了题目。

类似的题目还有43，64，102，120，131，144，170，179，186，192和204等。

我觉得这种原因推结论的题削弱方式有三种：1.原因本身是错的；2.原因本身推不出结果（有因无果的一种，一般是断开原因与结果之间的必要条件，即断桥梁）3.有其他因素使原因推不出结果（另一种有因无果，即它因削弱）

例子：第一种OG96 ， 第二种OG18，第三种OG68

总的来说因果结果的文章进行削弱都是说有其他原因，第一种和第二种都是在暗示有其他原因，但没具体说是什么其他原因，而第三种就是直接把其他原因说了出来

²        Begging the Question ( petitio principii )

Definition: The truth of the conclusion is assumed by the premises. Often, the conclusion is simply restated in the premises in a slightly different form. In more difficult cases, the premise is a consequence of the conclusion.

Examples: (i) Since I'm not lying, it follows that I'm telling the truth. (ii) We know that God exists, since the Bible says God exists. What the Bible says must be true, since God wrote it and
God never lies. (Here, we must agree that God exists in order to believe that God wrote the Bible.)

Proof: Show that in order to believe that the premises are true we must already agree that the conclusion is true. (Barker: 159, Cedarblom and Paulsen: 144, Copi and Cohen: 102, Davis: 33)