Physician: In order to investigate diseases caused by hormonal imbalances, a certain researcher wants to study, amon...

Antionette on December 10, 2013

Question

Why is B incorrect?

2 Replies

Melody on December 16, 2013

The physician's conclusion is that the "researcher's proposed study should be prohibited." Why? Because "medical research should be permitted only if it is likely to reveal important information about a medical condition and is known to pose only a minimal risk to the subjects."

We know "only if" introduces a necessary condition, so we can diagram the physician's general principle as follows:

MRP ==> LRII & KPOMR
not LRII or not KPOMR ==> not MRP

Conclusion: not MRP

To strengthen the physician's argumentation, we would want to invoke one of the two possible sufficient conditions (i.e. not LRII or not KPOMR) that will lead us to the conclusion that this proposed study should be prohibited.

(B) is incorrect because it doesn't help to justify the physician's argument. To conclude "not MRP," we must show either "not LRII" or "not KPOMR." The fact that 10,000 children have already been "given synthetic HGH without obvious side effect," does not tell us that it is not likely to reveal important information about the medical condition (not LRII), nor does it tell us that it is not known to pose only a minimal risk to the subjects (not KPOMR). 10,000 children having already been "given synthetic HGH without obvious side effect," actually points us to the research being "known to pose only a minima risk to the subjects," (KPOMR). That is merely one part of the necessary condition of the sufficient and necessary sentence and you cannot take the existence of the necessary condition and conclude the sufficient condition. Remember, you can't just reverse. You need to reverse and negate to get a valid contrapositive.

Notice that answer choice (E), on the other hand, points us to "not KPOMR" which will lead us to the conclusion of "not MRP."

Hope that was helpful! Please let us know if you have any other questions.

Marissa on June 24 at 11:36PM

Can you explain in greater detail how to invoke the sufficient conditions, and how that's related to answer choice E? I thought that is was too vague of an answer.