Anyone who fails to answer a patient’s questions cannot be a competent

Question

Anyone who fails to answer a patient’s questions cannot be a competent physician. That is why I feel confident about my physician’s competence: she carefully answers every one of my questions, no matter how trivial.

Which one of the following most closely parallels the flawed reasoning in the argument above?

(A) Anyone who grows up in a large family is accustomed to making compromises. Meredith is accustomed to making compromises, so she might have grown up in a large family.

(B) Anyone who is not in favor of this proposal is ill informed on the issue. Jeanne opposes the proposal, so she is ill informed on the issue.

(C) No one who likes music misses a performance of the symphony. Paul likes music, yet last week he missed a performance of the symphony.

(D) Anyone who works two or more jobs is unable to find a balance between professional and personal life. Maggie has only one job, so she can find a balance between her professional and personal life.

(E) No one who is hot-tempered and strong-willed will succeed in this business. Jeremy is strong-willed, so he will not succeed in this business.

IanStewart · Accepted Answer

This is testing the converse and contrapositive, which is something tested far more often on the LSAT than on the GMAT. Here the argument says "If a doctor does not answer questions, that doctor is not competent". If we just negate both of those clauses, to get "If a doctor does answer questions, that doctor is competent", then we're taking the converse of the original sentence. The converse is not generally a correct logical deduction -- "if x = 3, then x > 0" is clearly true, but the converse, "if x is not equal to 3, x is negative" clearly does not need to be true. What is always true is the "contrapositive" -- we must negate both clauses, but also reverse their order: "If a doctor is competent, that doctor answers questions" is a logically correct inference from the statements in this question, and "If x < 0, then x is not equal to 3" is a logically correct inference from the mathematical example I give above.

So here, we want an answer choice that is in the same form as the original argument: the premise must read "If X is true, then Y is true", and the conclusion must falsely read "X is not true, so Y is not true". Most answer choices here start "If X is true then Y is true" and conclude with "X is true, therefore..." so most are wrong for that reason alone. But D is a match: "If someone has two jobs, they cannot find balance" becomes, if we take the (logically invalid) converse "If someone does not have two jobs, they can find balance".

So here, we want an answer choice that is in the same form as the original argument: the premise must read "If X is true, then Y is true", and the conclusion must falsely read "X is not true, so Y is not true". Most answer choices here start "If X is true then Y is true" and conclude with "X is true, therefore..." so most are wrong for that reason alone. But D is a match: "If someone has two jobs, they cannot find balance" becomes, if we take the (logically invalid) converse "If someone does not have two jobs, they can find balance".

Thekingmaker · Answer

At last i could finish a question under 1 min 30 sec whoooleeee , now for the matter at hand , we have to find out an option that talks about two properties of a person which when done would lead to scucess not undertaking any other assumption when go out fishing we get to see that D stands out others not meeting the requisite criteria therefore IMO D

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Just smash those thumbs up button for guaranteed good luck for the next 2 years trust me it works

Fdambro294 · Answer

Classic “If/Then” type of formal logic that shows up on many LSAT questions

Not as important when it comes to GMAT questions.

However, the question is a good exercise for the brain

Posted from my mobile device

unraveled · Answer

I always falter in these If/then questions. 
The question mentions that there is flawed reasoning which we must identify in the choices, the one that parallels that reasoning is our choice.

However, what is the flaw in the original argument.

IanStewart · Answer

I explained this in a post earlier in this thread. This question tests one of the most common logic errors people make in day-to-day life, an error I think. you could be almost certain to see on any LSAT test. The error isn't tested nearly so often on the GMAT, and when it is, it's usually well disguised, so this question is one of those obviously-LSAT questions that won't be similar to any GMAT question you're likely to encounter.

The error is this: when a sentence that reads "If X is true, then Y is true" is logically correct, often people with think the logical "converse" is correct too: "If X is not true, then Y is not true". But the converse is not generally correct; it might be, or it might not be. So this sentence is presumably true:

If I go swimming, I get wet.

But if you take the converse, you no longer get something that is true:

If I don't go swimming, I don't get wet.

because people get wet when it rains or in the shower, say. What you can correctly infer, from a true sentence that says "If X is true, then Y is true", is something called the logical "contrapositive", which is a lot like the converse, but you need to flip the 'X' and the 'Y' -- the contrapositive here is "If Y is not true, then X is not true". Applying that to the first sentence above, you'd get this:

If I'm not getting wet, I'm not swimming.

which must be true if the original sentence is true. This question makes the same error: "If a doctor does not answer questions, the doctor is not competent" becomes, in the conclusion of the argument, its (logically incorrect) converse "My doctor answers questions, so my doctor is competent". That may or may not be true. What must be true is the contrapositive, but this isn't what the argument concludes with: "If a doctor is competent, that doctor answers questions." A doctor might need a whole lot of other skills and qualities, besides answering questions, to be competent though.

unraveled · Answer

Hey Ian,
Thanks for taking time to answer my query.
I read your earlier post and like it but could not understand the flaw in the argument.

"Anyone who fails to answer a patient’s questions cannot be a competent physician. That is why I feel confident about my physician’s competence: she carefully answers every one of my questions, no matter how trivial."

In the passage i took the matter as fact and didn't question it, and i think thats the reason i didn't notice the flaw. However, i am averse to this kind of question which is also the reason for my faltering. The moment i read something like "draws similar line of reasoning or parallells", i get jitters and most likely make a mistake.

Once again thanks for rephrasing the crux of the argument. I feel so dumb now as the reasoning looks so obvious.

IanStewart · Answer

The good news is, if you're taking the GMAT, it's very rare to see questions that are like this at all. I've maybe run into one or two official questions, out of thousands, that I'd say are similar to these LSAT parallel reasoning problems. So it's nothing to be concerned about. If, however, you're preparing for the LSAT, then you'd want to get comfortable with this type of question.

Ozzy11100 · Answer

This question tests identifying which answer choice confuses a "necessary" condition with a "sufficient" one.

The correct answer essentially says, "having, at most, one job is  necessary  to find balance; Jane has one job, therefore, she  definitely  has balance."

There are potentially a million OTHER factors which dictate whether Jane will have balance.

The logic is parallel to saying, " having a good education is necessary to become a self-made millionaire; John has a good education therefore he WILL become a self-made millionaire."

krndatta · Answer

KarishmaB  Ma'am,

In option B, 
Anyone who is not in favor of the proposal is ill informed. 
Necessary condition is taken to be sufficient. A person is not in favor, hence he is ill-informed. 
Jeanne opposes the proposal, hence she is ill-informed.

In this scenario too, we are taking a necessary condition to be sufficient.

Please evaluate my reasoning.

Thanks

krndatta · Answer

KarishmaB  Ma'am,

In option B, 
Anyone who is not in favor of the proposal is ill informed. 
Necessary condition is taken to be sufficient. A person is not in favor, hence he is ill-informed. 
Jeanne opposes the proposal, hence she is ill-informed.

In this scenario too, we are taking a necessary condition to be sufficient.

Please evaluate my reasoning.

Thanks

KarishmaB · Answer

If someone is not in favour, he is ill informed

Not in favour leads to being ill informed. So this is a sufficient condition. 
If A is not in favour, we can correctly say that A is ill informed. 
There is no flaw in this logic.

Note the wording of the original argument: If A (fails to answer), then cannot be B (competent).
So answering is necessary for being competent. It doesn't say that 'fails to answer' implies 'incompetent'. It just says that 'fails to answer' implies that one cannot be competent. So answering is necessary for competency. 
 
Note the wording of option (B): If A (not in favour), then B (ill informed)
Being 'not in favour' leads to being ill informed (is sufficient to be ill informed)

KarishmaB · Answer

Original Argument of the author: Premises: Anyone who fails to answer a patient’s questions cannot be a competent physician. My physician carefully answers every one of my questions, no matter how trivial. Conclusion: My physician is competent. The argument is flawed. Why? A necessary condition (must answer patient’s questions) to be competent is taken as sufficient to be competent. We need to find a similarly flawed argument. A necessary condition must be taken to be sufficient. (A) Anyone who grows up in a large family is accustomed to making compromises. Meredith is accustomed to making compromises, so she might have grown up in a large family. Here we have a cause effect relationship (large family leads to habit of making compromises). The presence of effect in Meredith (habit of making compromises) is taken as evidence of cause (she must have come from a large family). This is a different flaw. We discussed it in our flaws in logic section under “In a cause – effect relationship, presence of effect could be taken as evidence of presence of cause”. (B) Anyone who is not in favour of this proposal is ill informed on the issue. Jeanne opposes the proposal, so she is ill informed on the issue. This is a valid argument. Premises: Anyone who is not in favour of this proposal is ill informed on the issue. Jeanne is not in favour of the proposal Conclusion: She is ill informed on the issue. Hence, this is not similar to our original argument. (C) No one who likes music misses a performance of the symphony. Paul likes music, yet last week he missed a performance of the symphony. There is no conclusion in the argument. They are all facts, some of them conflicting with each other (No one who likes music misses a performance but Paul who likes music missed a performance). The author does not give any opinion of his own. Hence, this is not similar to our original argument. (D) Anyone who works two or more jobs is unable to find a balance between professional and personal life. Maggie has only one job, so she can find a balance between her professional and personal life. If someone works two or more jobs, they cannot find balance. Only if someone has one job, can they find balance. Maggie has only one job. So, Maggie can find a balance. The necessary condition (one job) is taken to be sufficient here to find balance. It is the same flaw as our original argument. Correct. (E) No one who is hot-tempered and strong-willed will succeed in this business. Jeremy is strong-willed, so he will not succeed in this business. The premise gives us that if a person is hot-tempered and strong-willed, he will not succeed. We are given that Jeremy is strong-willed but nothing is mentioned about his temper. Hence, we cannot conclude anything. A necessary link is missing. The flaw is not the same as our original argument flaw. Answer (D) Discussion on Mimic Questions: https://youtu.be/dHU17plF2mc

Anyone who fails to answer a patient’s questions cannot be a competent

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