Critical Reasoning

harshavardhanc,
Weaken questions cannot directly attack the conclusion. Why? coz conclusion is not self formed.It rests on the data provided by the premise and assumptions. So in order to weaken an argument, the choice must weaken either the premise or the assumption. I agree with you point that the conclusion contains the statement- therpaists cannot perform them together, but how did this statement arrive? Remember conclusion just rests on the premise and assumption and cannot stand alone by itself.
Supoose if the argument was written this way:
premise 1: reporting the clients unreported crimes violates the clients trust but remaining silent leaves the dangerous client out of prison, free to commit more crimes.
Premise 2: There is no other way the 2 can be perfomed together.

Conclusion: Therpaists cannot perform the both events at the same time.

Now our premise 2 is the assumption. Technically speaking it is called the Defender assumption.
A defender assumption is different from the normal, supporter assumption
A supporter assumption- connects the missing piece in the jig saw puzzle whereas A defender assumption maintains the status quo of the argument.
Here in our case at hand too, we have a defender assumption. This maintains the status quo of the passage to mean that there is no other way the two can be performed together. An assumption need not always be a new piece of information that connects the premise and the conclusion. It can also serve as a guard, guarding the status quo of the argument. In this case the assumption performs the role of the guard. Note: Defender assumptions are usually applied in strong arguments. Weak arguments generally themselves have so many flaws that a supporter assumption is required to validate the conclusion.
One way of identifying which assumption is employed, is to check the strength of the argument. If the argument is strong then an assumption to maintain the status quo of the passage will generally be employed.

Hope this helps!

fibbonnaci wrote:harshavardhanc,
Weaken questions cannot directly attack the conclusion. Why? coz conclusion is not self formed.It rests on the data provided by the premise and assumptions. So in order to weaken an argument, the choice must weaken either the premise or the assumption. I agree with you point that the conclusion contains the statement- therpaists cannot perform them together, but how did this statement arrive? Remember conclusion just rests on the premise and assumption and cannot stand alone by itself.
Supoose if the argument was written this way:
premise 1: reporting the clients unreported crimes violates the clients trust but remaining silent leaves the dangerous client out of prison, free to commit more crimes.
Premise 2: There is no other way the 2 can be perfomed together.

Conclusion: Therpaists cannot perform the both events at the same time.

Now our premise 2 is the assumption. Technically speaking it is called the Defender assumption.
A defender assumption is different from the normal, supporter assumption
A supporter assumption- connects the missing piece in the jig saw puzzle whereas A defender assumption maintains the status quo of the argument.
Here in our case at hand too, we have a defender assumption. This maintains the status quo of the passage to mean that there is no other way the two can be performed together. An assumption need not always be a new piece of information that connects the premise and the conclusion. It can also serve as a guard, guarding the status quo of the argument. In this case the assumption performs the role of the guard. Note: Defender assumptions are usually applied in strong arguments. Weak arguments generally themselves have so many flaws that a supporter assumption is required to validate the conclusion.
One way of identifying which assumption is employed, is to check the strength of the argument. If the argument is strong then an assumption to maintain the status quo of the passage will generally be employed.

Hope this helps!

I completely understand what you have written above and do get the point you are trying to make, but....... (ooohh that but again..., I hate it but can't help )

In fact, weakening questions leave the conclusion to be targeted and and generally, in this type of question, success is realized by selecting an option which attacks the conclusion. Conclusion IS the most vulnerable part and needs to be hit . Also, there NEED not be an assumption always to have a conclusion. If the author feels that just the premise is enough, he can conclude based on it.

I'm sure that you must have read various texts on CR strategy, including Powerscore. You might want to check the section about "weakening" questions again.

I can see that you are viewing "weakening" as opposite to "strengthening" questions and hence, you are referencing the supporter / defender model. But remember that strengthening, as opposed to "weakening" type, will and does make use of assumptions. Whereas, weakening NEED and MAY not always do that.

So, this argument can go on and on and we both will enjoy it , but it will be good if an instructor can also pitch in .

received a pm.

Technically, a weakener is a fact that renders the conclusion less likely to follow from the evidence, which I believe is Fibo's position.

Practically, this means that a weakener will also often render the conclusion less likely, which is what Harsha is saying.

How will a weakener render the conclusion less likely (to follow from the evidence)? On the GMAT, it will almost always be by attacking the assumption; if a fact tends to refute the assumption, then the conclusion is thereby less likely to follow from the evidence, and the argument is weakened.

Here:

The first sentence of the argument is conclusion: therapists cannot simultaneously respect client confidentiality and be sincerely concerned about the welfare of those who may be harmed by their clients. The second sentence is evidence.

The author's assumption is that the one piece of evidence he discusses is sufficient to establish that therapists cannot simultaneously respect client confidentiality and be concerned about social welfare.

Choice E directly targets this assumption, and is therefore a weakener.

Just to clarify:

Also, there NEED not be an assumption always to have a conclusion. If the author feels that just the premise is enough, he can conclude based on it.

This is incorrect. In all assumption, strengthen/weaken, and flaw questions, the arguer makes an assumption. If the author feels that the premise is sufficient, then that itself is an assumption (that's what happened in this argument). If there weren't an assumption, then the author's conclusion would be necessarily true-- a valid inference; and, of course, valid inferences don't stand in need of strengthening, and cannot be weakened.

I can see that you are viewing "weakening" as opposite to "strengthening" questions and hence, you are referencing the supporter / defender model.

I am not familiar with supporter/defender model, but weakening an argument is exactly the "opposite" of strengthening. In fact, this is why we can use denial test in stn/wkn questions: if the opposite of a fact (ie, a denied answer choice) strengthens, then the fact itself (ie, original answer choice) is a weakener.

For example, if an answer choice stated that "a study was NOT representative", then that will clearly weaken the argument based on that study. The denied fact would be "a study WAS representative", and that would cleary strengthen the argument that was based on that study.

As a matter of strategy, using denial test is often helpful in strengthen question's answer choices that use negative language such as "not"; in these cases, it is often easier to see what impact a denied fact will have on the argument (as opposed to the original fact.)

Testluv wrote:
As a matter of strategy, using denial test is often helpful in strengthen question's answer choices that use negative language such as "not"; in these cases, it is often easier to see what impact a denied fact will have on the argument (as opposed to the original fact.)

Thanks Testluv! That's very insightful! But, I'll continue this discussion as I need to quench my thirst.

Consider this argument :

....hence, X can be accomplished by Y.

The author here concludes that to reach X, there is one and only one method - Y. He assumes non-existence of any alternate way to reach X. Weakener in this case is an option which shows that there are, in fact, other ways to reach X. We hit the ASSUMPTION : "non-existence of any alternate way".

I'm not denying that this type of weakener question exists, as I've come across such a type may a times.


Now consider this :

....hence, there is NO way to accomplish X.

The author concludes that there is NO way X can be accomplished. Weakener in this case is an option, which shows that there exists a way to do so. We hit the "non-existence" part again, but here it is contained, rather is the conclusion.

The point which I'm trying to make is that there IS a difference between the two cases. I know that assumptions are unstated and we are precisely hitting the invisble part in the first case. But in the second one (and our question), we are clearly targeting something which we are able to see in black letters on our screen.

Please, think about it and let me know your views on this one. It is definitely food for thought.

Now coming to your "further-explanation"

Testluv wrote:if the opposite of a fact (ie, a denied answer choice) strengthens, then the fact itself (ie, original answer choice) is a weakener.

always?

Consider this argument:

A person who can write a computer program knows how to use a computer. Therefore, X knows how to use a computer.

and one of the answer choice said:

> X was seen writing a computer program this afternoon.

I agree that this option would definitely strengthen the argument. But, did you mean its negation : " X was not seen writing a computer program this afternoon" weakens the argument. How ?

OR :

I sit at home when it rains. Hence, on Friday at 8:00 AM it was raining.

one of the option said :

> I was watching a movie on Friday at 8:00 AM in my house.

a "strengthener" for the case in hand. But is the negation a weakener?


As far as I know, if P IMPLIES Q, NOT P does not necessarily IMPLY NOT Q. This comes from the principles of Discrete Maths.

Again, please correct me if I'm wrong somewhere in my reasoning.

Testluv wrote:As a matter of strategy, using denial test is often helpful in strengthen question's answer choices that use negative language such as "not"; in these cases, it is often easier to see what impact a denied fact will have on the argument (as opposed to the original fact.)

I know you said "often" above, but further conditions to apply negation technique should be metioned as well. The negation technique works when the strengthener/weakener is an assumption. Again, I will take help from Discrete Maths & Logic principles.


Consider an argument which has a premise P, an assumption Q and a conclusion R. Birds eye view of this argument :

P together with Q implies R.

or according to the author, R hold true when P and Q each hold true.


in Logic principles it is P AND Q => R.

when the conclusion holds true, R is 1. For this to be true, P and Q each has to be 1 . i.e 1 AND 1 = 1 or P and Q each should be true. ( in sync with our normal english)

(binary value 1 means occurrence and 0 means non-occurrence)


when we negate the assumption Q, we basically make the value of Q as 0. And when we multiply P (1) with Q (0), R becomes 0.

You normally call this " the conclusion falls apart". Hence, we conclude Q is a necessary assumption. Hence, when finding a necessary assumption or a strengthener/weakener, which is an assumption, negation technique works.

But, in the cases mentioned above, where the option just supports from outside and is not an assumption, negation technique won't help. That is what happened in the examples above.


Hope you agree with me!