#11 - People who browse the web for medical information

[danielacvazq]

Part of my confusion with this question is that I thought searching medical information online for the purpose of diagnosis was the new element introduce in the conclusion, so I chose A. Should I have not assumed that and diagnosis is covered under the umbrella "browsing the web for medical information"?

[Luke Haqq]

Hi danielacvazq!

You're right to identify diagnosis as a new element that appears for the first time in the stimulus. The problem with (A) is that it doesn't then connect this to the distinction made between scientifically valid information and quackery. Answer choice (B) does this, however, which is why it is able to bridge a connection between the premises and the new element in the conclusion.

[DaveFromSpace]

I removed a lot of qualifiers to really simplify and focus on the crucial parts of the argument:

P: People who surf the web can't tell real from nonsense

C: People who rely on the web are likely to harm themselves

The necessary assumption (B) tells us:

People are likely to harm themselves unless they rely 100% on real.

This doesn't seem like a necessary assumption and feels closer to a sufficient one. What happens if the threshold is 99%? It seems like the argument still works.

It feels like the necessary assumption should be:

People are likely to harm themselves unless they rely on at least some (1-100%) real.

To reword this back into the actual language of the test:

Unless you rely on at least some scientifically valid information, you're likely to do yourself more harm than good.

This is obviously insufficient, but it seems necessary. But saying you need 100% scientifically valid information seems too extreme to be necessary, and indeed, it's nearly sufficient to necessitate the conclusion.

This question is making my head spin, I'd love if someone can chime in here.

[Adam Tyson]

I like your simplification here, DaveFromSpace, although I think you may be misunderstanding the answer. Try looking at it this way, the contrapositive of your paraphrase:

If you rely on any of that nonsense (if not 100% real), you're probably going to hurt yourself.

Isn't that what the author is assuming? Most of it is quackery, so you'll probably hurt yourself. They must assume that quackery is harmful nonsense!

Now consider a negation of that answer, something like:

"Nah, you'll probably be okay if you rely on some amount of nonsense."

That ruins the argument, proving it is a necessary assumption.

[serenapao]

Hi! I chose the correct answer (B) because the other answers did not seem to strengthen the argument. I understand why (B) would be correct if the question were a strengthen or pseudo-sufficient assumption question, but not why it is correct as a necessary assumption (NA) question.

1. Based on what I've been learning, overinclusive or overly broad rules are fine for other Strengthen questions but not for NA. So, I get why (B) is better than the other answer choices but don't see why it is a NECESSARY assumption. "People who attempt to diagnose their medical conditions" seems overly broad because the subset of people discussed in the stimulus are specifically people relying on the web to attempt to diagnose their medical conditions, not all people who attempt to diagnose. Therefore, I thought that this rule was not necessary; a narrower rule would do the job just fine.

2. My second question about (B) is whether or not it's strong enough to also constitute a sufficient assumption.

Thanks!

[Luke Haqq]

Hi serenapao!

To your first question, it's certainly possible to have quite broad answer choices that accurately convey a necessary assumption. In many cases, like here, there's a bridge that needs to be made between the premises and a new element introduced within the conclusion. In particular, this conclusion adds the element of likely doing themselves more harm than good.

(B) refers to "people who attempt to diagnose their medical conditions," which is broad enough to capture people who use the web to do so as well. I can see an argument that the answer choice could have been worded more specifically to refer just to those who use the web to diagnose their conditions, but the fact that it is broader doesn't seem to count against it in the end. After all, if you apply the Assumption Negation technique, this argument falls apart--as Steve notes above, negated, (B) would be "Even if people don't rely exclusively on scientifically valid information, people who self diagnose are not likely to do themselves more harm than good." If that were true, it wouldn't follow that people are likely to do themselves more harm than good if they rely on the web when attempting to diagnose their medical conditions.

My understanding of your second question is whether (B) would also be correct for a justify the conclusion type of question (which asks for what is sufficient for the conclusion to follow). I don't see it as being correct for that type of question, but feel free to elaborate on your reasoning if you think it is.

[serenapao]

Hi Luke,

Thank you so much for your response. I really appreciate it, especially what you mentioned about the negation test. I am using both PowerScore books and the 7Sage curriculum to study, and on 7Sage, it says, "Recall that a rule's being over-inclusive wasn't a defect for PSA. On the contrary, it was a strength. But here in NA, a rule being too strong or over-inclusive renders the rule unnecessary and hence is a defect." Based on your explanation to this question, is that not true?

I thought it would be sufficient because it fully bridges the gap between the premise and conclusion. If that's not the case, is it possible to further strengthen this assumption to make it a sufficient assumption? Or is there another gap in the reasoning that I'm missing?

Thanks so much!

[Dave Killoran]

Hi Serena,

I don't think that is what Luke's explanation is getting at, and if he was writing this for a book, as opposed to a casual forum, he'd have stated the "broad enough to capture people" differently. He was trying to draw a line of connection there, nothing more.

In NA/Assumption questions, extra info is of course a problem, and grounds to kill an answer. On the Strengthen/SA/Justify side, that's not the case. When I look at the argument, the "web" aspect is already connected between the premise and the conclusion: "People who browse the web for medical information" to "people who rely on the web when attempting to diagnose their medical conditions." Thus, when looking for the missing piece here, I doubted I'd see "web" or at least knew it wasn't necessary to appear in the answer. But what I did need was to connect the idea of diagnostic likelihoods in the conclusion to the scientifically valid information in the premise. That's what (B) does, and without it we'd have a hole in the argument, which the Assumption Negation Test reveals.

Please let me know if that helps. Thanks!

[serenapao]

Hi Dave,

Thank you for your response. So because the "web" aspect is present in both the premise and conclusion, the missing piece doesn't have to be as specific because it's implied that it's under the domain that the rest of the argument is under?

Thanks!
Serena

[Dave Killoran]

It's more like we have that common box checked so it's not a missing piece in the argument. Imagine the following argument:

• Premise: A B
  Premise: C D
  
  Conclusion: A D

Note how A and D are both common to the premise and conclusion, but what's missing is the B C connection. Thus, in an NA/Assumption question that would be the right answer. Fwiw, it would also be the right answer in an SA/Justify question, which shows some of the overlap we can see between these two question types.

Thanks!