Critical Reasoning

I already know the term "Logical opposition"&"polar opposition", but it's not easy to distinguish them as they look like.
For example. What's the "Logical opposition" of "will"? I was told it is might/may not ("will not" is polar). But I really do not know why!
Another one "require". I thought it should be the same case with "will". However I even cannot convince myself that the "Logical opposition" of "require" is "might require". It must be "not require", but what's the difference between "will"&"require"? How to negate a verb? Is there any rule?
Can someone help me?

Lets take three sentences

"It will rain tomorrow" . It's CERTAIN that it will rain tomorrow.
"It might rain tomorrow." It's UNCERTAIN that it will not rain tomorrow.
"It will not rain tomorrow." It's CERTAIN that it will NOT rain tomorrow.

Logical opposite of CERTAIN is ANYTHING other than CERTAIN i.e UNCERTAIN {WILL rain or WILL NOT rain}
Polar opposite of WILL Rain is WILL NOT Rain .

Logical opposite is always a bigger set than polar opposite , because polar opposite is always a subset of logical opposite.

One simple example is .
Logical opposite of CORRECT is INCORRECT.
Polar opposite of CORRECT is WRONG.

Here when you say INCORRECT --> it can mean either WRONG OR NEUTRAL

{WRONG} (polar opposite) is a subset of {WRONG, NEUTRAL} (logical opposite)

Hope its clear!

Thank you smackmartine ! It really helps!
I suddenly realize "will/ must/can..." are Auxiliary verbs. They are totally different from normal positive verb such as "require".
Can I say, when we negate a verb in GMAT CR answer choices, if the verb is an auxiliary verb, we can not just add "not". Because Logical opposite is always a bigger set than polar opposite in this case.
However, if the verb is a normal positive verb (other than Auxiliary verbs) such as "require/ need/ run...", we can just add "no/not" to negate. Because, in this case, Logical opposite& polar opposite are the same!
AM I RIGHT?

I would suggest that try to refrain from using NO / NOT as these words are strict and eliminate any chances of grey area that is required in logical opposites. I do not see any such rule, try to use it questions directly or you may post the sentences in which you are facing difficulty.

All of the examples I quoted are from this forum.(I just search "negate" in this forum and get those. ). Original link is provided.

Diabetes is a disease in which the body does not produce or properly use insulin, a hormone that is needed to convert glucose into energy needed for daily life. Because ice cream commonly contains glucose in the form of sucrose, diabetics generally experience discomfort after consuming even a small serving of ice cream. However, since there are several ice cream companies who add sucrose to none of the ice cream they produce, diabetics are able to eat ice cream without experiencing discomfort due to glucose intolerance afterward. Which of the following is an assumption on which the argument depends?
(A) These ice cream companies have been able to duplicate the taste of sucrose derived from glucose by means that do not involve adding any potential substances that may be of discomfort to diabetics.
(B) Not all forms of glucose are equally likely to result in this discomfort.
(C) Ice cream is not the only food to which glucose is commonly added.
(D) Apart from glucose, there are no substances commonly present in ice cream that would cause discomfort to diabetics.
(E) Glucose is not naturally present in the ice cream produced by these ice cream companies in amounts large enough to cause discomfort to diabetics who eat this ice cream.
Answer E
mundasingh123 wrote:
Adam,How to Negate A ?
AdamKnewton wrote( Instructor):
We'd simply add a "not" before the main verb, so that it read: "These ice cream companies have NOT been able to duplicate the taste of sucrose...." This statement does not affect the Conclusion since it still refers to taste. I think your question is about whether this is the correct Negation or if we should negate the "do not" part later on: when using the Negation Test, always negate the main verb of the answer choice.

https://www.beatthegmat.com/knewton-chal ... 21-15.html

Brian@VeritasPrep said:
Hey guys,

Great thread! Assumption negation isn't an exact science, so you may need to try more than once to find a negation that fully clicks, but the two major ways to negate a sentence are:

1) Negate a universal or particular modifier in the dominant clause of a sentence:

All mammals have lungs ---> NOT ALL mammals have lungs
Some birds cannot fly ---> NO birds cannot fly

In the presence of modifiers like "some", "all", "none", "never", "not all", you'll want to negate that modifier to take the logical opposite.


2) Negate the verb in the dominant clause of the sentence:

Many physicians generally oppose insurance company regulations --> Many physicians generally DO NOT oppose insurance company regulations

Note here that everything in your initial sentence after the word "that" is a dependent clause...the dominant clause of the sentence is that first part, so that's where you'd negate. Note also that "many" doesn't have a direct logical opposite (whereas "some" would go to "none"), so you probably won't have much luck trying to negate "many", and that's why you'll then want to move on to the verb and try to negate there.

Now, the benefit is that when the correct answer is negated, it should pretty obviously violate the conclusion, so that's why even if you have to try to negate at more than one point in a particular answer choice it's not a huge problem. If one of those negations directly undermines the conclusion, that's your answer...
Original thread https://www.beatthegmat.com/negation-tec ... 75374.html

Hi,

I have read both of the above posts but could not make out where you are facing difficulty....

vikram4689 wrote:Hi,
I have read both of the above posts but could not make out where you are facing difficulty....

you said we should "refrain from using NO / NOT... " ,but in those examples they just add a "not" before the main verb in order to negate a verb. So I am confused.
Maybe I misunderstand you?

Ya one should refrain but there are cases like these when NOT is to be uses. Our main aim is to create a LOGICAL OPPOSITE which is a super-set of POLAR OPPOSITE and creating a LOGICAL OPPOSITE depends on the context of sentence. One way you could build on this is by solving assumption ques and using this technique on correct option. If there is any ques. on which you are stuck then you may post it here.

vikram4689 wrote:Ya one should refrain but there are cases like these when NOT is to be uses. Our main aim is to create a LOGICAL OPPOSITE which is a super-set of POLAR OPPOSITE and creating a LOGICAL OPPOSITE depends on the context of sentence. One way you could build on this is by solving assumption ques and using this technique on correct option. If there is any ques. on which you are stuck then you may post it here.

I am with you vikram! I also think it is dangerous to use NO/NOT to negate a verb. But I find out that, when we face a assumption question, simply to add/ get rid of "no/not" always work--break the argument. So I really want to know in which circumstances we should not use NO/NOT (I already know Auxiliary verbs--will/ must/can...) and in which circumstances we can just add NO/NOT. When I negate a answer choice, I cannot make sure. That's why I post this thread.

Lets go ques. by ques. Post the question which you tried and faced problem.