关于assumption题取非的一个疑问！！

clumsy123

请问NN们，对于assumption的题目，对正确选项取非后，是会削弱原文结论 还是会使原文结论完全不能成立呢？

我在manhattan的CR看到说，assumption是必要条件，若原文缺少它一定不能成立；但我在CD上看到许多人分析帖子的时候，都是说削弱~~~毕竟削弱和不成立还是有很大差别的，请牛人指点啦！！

sdcar2010

For NECESSARY assumption, if you negate the correct answer, the argument 完全不能成立

For SUFFICIENT assumption, negation method won't work.

clumsy123

For NECESSARY assumption, if you negate the correct answer, the argument 完全不能成立

For SUFFICIENT assumption, negation method won't work.

-- by 会员 sdcar2010 (2011/3/31 20:51:03)

也就是说assumption有两种？

gelilong

assumption 在逻辑上就是假设，应该为必备。至于为什么削弱，我想可能和个人定义和逻辑题目的结论有关，比如一个结论“a 产品是同类中最好的”
那么，如果否定一个必须的assumption，那么结论就变成“a 产品不是同类中最好的”。
一些人认为结论从“最好的”变为为“不是最好的”，好像就是削弱了，但其实，这一变化等于是完全否定了“a 产品是同类中最好的”，题目的结论被完全推翻了。
很多的时候逻辑题目的结论是定量的不是定性的，这时候的削弱和否定结论就比较类似了

sdcar2010

Both Necessary Assumption and Sufficient Assumption questions contain the word "assumption", but they ask for different things. So how could you tell the difference?

FOCUS on the verb in the question stem.

Necessary Assumption questions often contain the words:

1) Depend
Example #1: "Which one of the following is an assumption that the manager's argument depends on?"

Example #2: "Which one of the following is an assumption on which the argument depends for its conclusion to be properly drawn?"

2) Require
Example: "Which one of the following is an assumption the President's argument requires?"

Example: "Which one of the following is an assumption required by the dietitian's argument?"

3) Rely
Example: "Which one of the following is an assumption on which the argument relies?"

4) Necessary
Example: "Which one of the following is an assumption necessary for the critic's conclusion to be properly drawn?"

Sufficient Assumption questions often contain the following words:

1) Follow logically if something is assumed
Example #1: "The argument's conclusion follows logically if which one of the following is assumed?"

Example #2: "The critic's conclusion logically follows if which one of the following is assumed?"

2) Properly inferred if something is assumed
Example: "Which one of the following, if assumed, allows the conclusion of the doctor's argument to be properly inferred?"

3) Properly drawn if...assumed
Example: "The argument's conclusion is properly drawn if which one of the following is assumed?"

4) Enable
Example: "Which one of the following, if assumed, enables the conclusion of the argument to be properly drawn?"

5) Allow
Example: "Which one of the following is an assumption that would allow the conclusion above to be properly drawn?"

6) Justify
Example: "Which one of the following is an assumption that would serve to justify the conclusion above?"

clumsy123

Both Necessary Assumption and Sufficient Assumption questions contain the word "assumption", but they ask for different things. So how could you tell the difference?

FOCUS on the verb in the question stem.

Necessary Assumption questions often contain the words:

1) Depend
Example #1: "Which one of the following is an assumption that the manager's argument depends on?"

Example #2: "Which one of the following is an assumption on which the argument depends for its conclusion to be properly drawn?"

2) Require
Example: "Which one of the following is an assumption the President's argument requires?"

Example: "Which one of the following is an assumption required by the dietitian's argument?"

3) Rely
Example: "Which one of the following is an assumption on which the argument relies?"

The following three are significantly less common:

4) Necessary
Example: "Which one of the following is an assumption necessary for the critic's conclusion to be properly drawn?"

"Assumes"

Sufficient Assumption questions often contain the following words:

1) Follow logically if something is assumed
Example #1: "The argument's conclusion follows logically if which one of the following is assumed?"

Example #2: "The critic's conclusion logically follows if which one of the following is assumed?"

2) Properly inferred if something is assumed
Example: "Which one of the following, if assumed, allows the conclusion of the doctor's argument to be properly inferred?"

3) Properly drawn if...assumed
Example: "The argument's conclusion is properly drawn if which one of the following is assumed?"

4) Enable
Example: "Which one of the following, if assumed, enables the conclusion of the argument to be properly drawn?"

5) Allows
Example: "Which one of the following is an assumption that would allow the conclusion above to be properly drawn?"

6) Justifies
Example: "Which one of the following is an assumption that would serve to justify the conclusion above?"

-- by 会员 sdcar2010 (2011/4/1 8:25:05)

解释的非常清楚！！谢谢！！