#11 - People who browse the web for medical information

[Lina]

Thanks! Where in the coursebook can I find a review of these concepts? I have always had a bit of trouble with negating.

When negating, does 'unless' turn into 'even if' ?

[Lucas Moreau]

In the Full-Length Coursebooks, the opposites, negations, reversals, and the Unless Equation(tm) are all in Lesson 2, the first coursebook.

Lucas Moreau
PowerScore

[emilysnoddon]

I understand why answer choice B is correct based on the assumption negation application used above but I had trouble logically negating answer choice E and as a result chose that answer. Can you please show me the correct logical negation of answer choice E?

Thank you,

Emily

[Nikki Siclunov]

Hi Emily,

Answer choice (E) contains a conditional statement, which can be diagrammed as follows:

Do more harm than good Rely on quackery instead of valid info

To logically negate this answer choice, you need to show that the sufficient condition can occur even in the absence of the necessary condition. In other words, the logical opposite of answer choice (E) would state,

People can do themselves more harm than good even if they don't rely on quackery to diagnose their medical conditions.

In other words, you can harm yourself even if you use scientifically valid information. Nobody said that relying on scientifically valid information precludes the possibility of harm, which is why the logical opposite of answer choice (E) has no bearing on the conclusion of the argument.

Let me know if this helps!

Thanks,

[sgd2114]

Hi,

I chose (B), but wanted to make sure I am negating this answer choice correctly. Is the correct negation of (B) the following:

People who attempt to diagnose their medical conditions are not likely to do themselves more harm than good even if they rely don't rely exclusively on scientifically valid information.

I guess I am concerned about the conditional reasoning - usually we negate the necessary (e.g., "A unless B" which is diagrammed as Not A B would become "Not A even if Not B"), correct? So in the case of (B) would we negate the "are not likely" as well as the conditional statement? The negated answer above sounds correct to me, in that it kills the argument in the stimulus.

My apologies if this is unclear. Thanks for the help!

[Adam Tyson]

It's pretty clear to me, sgd2114, and you are doing fine work here in my opinion. Negations of statements like this one are tricky at times, but your use of the "even if not" approach is a solid one. The goal here is to show that the necessary condition isn't really necessary; the sufficient condition can happen and the alleged necessary condition not happen, and you're still okay. If that ruins the argument, you've found yourself a winner - which you did!

I would probably have negated answer B the same way as you did, but there is another way to go about it, and that's by taking a more holistic approach. What does the answer mean? It means these people are headed for trouble - they are going to harm themselves if they rely on the quackery. Without reference to the exact text of the answer, but instead to the "real" meaning of the statement, you can negate it by saying "quit worrying, they'll be fine!"

That more holistic approach is certainly not the recommended one, but when negations get tricky and you aren't sure you're doing it right, but you understand what the original claim is saying, try using this as a backup plan to help clarify your understanding.

Nice job! Keep doing that!

[ds72]

Will you please show me how to properly negate answer choice E. I always confuse myself when I have to negate conditional statement with "only if"

[AthenaDalton]

Hi ds72,

The phrase "only if" can be treated the same way as the word "only." Whatever term is modified by the word "only" is the necessary condition. So here's the diagram of (E):

Original: Will do more harm than good Rely on quackery

Contrapositive: Not rely on quackery Will not do more harm than good

Don't confuse "only if" with the phrase "if and only if." The phrase "A occurs if and only if B occurs" creates two conditional statements at once: (1) A occurs only if B occurs; and (2) B occurs only if A occurs. It would be diagrammed like this:

A B

I hope this helps. Good luck studying!

[Strongam]

Hello,

I am confused as to why answer choice B is an acceptable answer. Here is my reasoning:

The question does not use any words such as "most" or "a majority" to signify how many "people who browse" are those with "no medical background." It tells us that "much of the quackery is appealing," but that does not necessarily indicate how much of the quackery is actually accepted and relied upon nor does it say what proportion of people accept and rely upon it.

Answer choice B speaks of "people" who (in order for this answer to be true) would need to have the capacity to distinguish between scientifically valid information and quackery and who would also then choose to rely upon the scientifically valid information. I don't see where this specific group of "people" is mentioned in the question stem. It seems to me that the people spoken of here are not specified in the premises nor in the conclusion. Thus, I cannot see why this assumption is correct.

I chose answer C, which I don't think is foolproof, but at least it spoke of a specific group of people "people who have sufficient medical knowledge."

I apologize if my analysis is unclear, it is difficult for me to describe my reasoning because the question and answer choices seem so poor. Any help would be appreciated!

Thank you,
Strongam

[Francis O'Rourke]

Hi Strongam,

You are correct that the stimulus does not tell us much about the proportion of people who cannot distinguish valid from invalid information. The word "often" tells us that there are many people, but - as you said - we don't know if this is more than half, or less than half of the people who browse the web for medical information.

I am a bit confused about your explanation of answer choices (B) and (C). You may have misinterpreted what the task was in this question. The question stem asks us to identify something that the author needs to believe for the argument to make sense. It seems like you are trying to refute answer choice (B) because the stimulus does not provide evidence for that answer choice. That sounds like you are treating this question as a Must Be True question.

Because we are looking for a necessary assumption in this question, we do not have to rely on the information in the stimulus to prove the answer choice. Rather, we are looking for something that the speaker did not include, but needed to.

Let me know if this is helpful, and if I understood your post correctly.