OG-51, do I have a right understanding?

cranberry

不明白什么是假设命题，命题是哲学中的逻辑概念，是一个判断。

dream1111

以下是引用lawyer_1在2004-9-14 22:58:00的发言：

“这样说来，表示充分必要关系需要有一些关键词了，譬如if，only if, unless等等。而在gmat的题型中，只有assumption是必要条件。其他的譬如support和weaken除了可以对充分必要条件作用外，也可以对因果关系作用，是不是？” 非常正确。GOOD GENERALIZATION。充分必要需要INDICATOR，因果关系不需要，他们范畴不同规律也不同。

?1.

  "只有assumption是必要条件", my understanding on this sentence above is that in terms of the argument of the question as a whole, the correct choice is required. But obviously we are talking about the reasoning relation( who is sufficient and who is required) in argument itself.

?2.

even if  we leave the word--' because' unconsidered, the argument of this question itself  does present an apparent reasoning relation, and choice E does as well.  in a nother word we do not have to judge its reasoning by some key word such as here the 'because', since 'because' is not a indicator of reasoning relation as you said . However, the such relations do exist in this question.

for example: in argument , I think, the relation is that IF the strings die soon, THEN they must be contaminated by oil or dirt.

in choice E , that IF smearing oil, THEN the strings will die soon. or that IF smearing oil, THEN the strings will not die soon.

In fact, the obvious inconsistence of reasoning between argument and choice is just my question.  Because of this, I have to reconsider the reasoning in argument  and convert the place of IF and THEN.  What do you think?

lawyer_1

逻辑的判断分直言判断和复合判断，复合判断又分假言判断，选言判断，联言判断和负判断。我们逻辑题中的充分条件，必要条件就是来源于假言判断。

dream1111

以下是引用lawyer_1在2004-9-13 22:56:00的发言：

1。原文的responsible和E选项的causes是因果关系，因果关系不同充分必要关系。后者有推理关系，前者是归纳的范畴，没有推理关系（MUST BE）关系。

2。E对的原因是EVALUATION题对选项YES和NO能对原文起支持和削弱作用即是答案，不是MUST BE结论。

Generally, it is true that  因果关系不同充分必要关系, but in CR here, all my logic thinkings are based on 推理关系, without it I can not check my choice. Then may i ask you what the  归纳的范畴 is and how to reason the 因果关系?

lawyer_1

简单讲，因果关系没有MUST BE关系，充分必要有MUST BE关系。其他的比如出现向后的区别与逻辑关系不大。

shirley_zhu

以下是引用lawyer_1在2004-9-14 22:58:00的发言：

“这样说来，表示充分必要关系需要有一些关键词了，譬如if，only if, unless等等。而在gmat的题型中，只有assumption是必要条件。其他的譬如support和weaken除了可以对充分必要条件作用外，也可以对因果关系作用，是不是？” 非常正确。GOOD GENERALIZATION。充分必要需要INDICATOR，因果关系不需要，他们范畴不同规律也不同。

请问LawyerNN，那么这样理解的话，因果型和充分必要型的区分，就是看有没有提示充分必要关系的连接词如if, only in, unless等，如果没有就表示是因果关系，就不能用他因法削弱了，是这样吗？

KATIEUS